有机化学英文版论文
有关化学的英文摘要作文
有关化学的英文摘要作文英文：Chemistry is a fascinating subject that deals with the study of matter and the changes it undergoes. It is a branch of science that is closely related to our daily lives, from the food we eat to the air we breathe. As a chemistry enthusiast, I have always been intrigued by the way different substances interact with each other and the amazing reactions that take place.One of the most interesting topics in chemistry is the concept of chemical bonding. Chemical bonding is the process by which atoms combine to form molecules or compounds. There are different types of chemical bonds, such as ionic bonds, covalent bonds, and metallic bonds. For example, when sodium (Na) and chlorine (Cl) react, they form an ionic bond to create sodium chloride (NaCl), which is common table salt. Understanding chemical bonding is crucial in explaining the properties of differentsubstances and predicting how they will behave undercertain conditions.Another captivating aspect of chemistry is the study of chemical reactions. Chemical reactions occur when substances are mixed together and undergo a change to form new substances. For instance, when hydrogen gas (H2) reacts with oxygen gas (O2) in the presence of a catalyst, itforms water (H2O). This process, known as the synthesis of water, is a fundamental reaction that is essential for life. Chemical reactions play a vital role in various industries, such as pharmaceuticals, agriculture, and manufacturing.Furthermore, the field of organic chemistry is particularly intriguing as it focuses on the study ofcarbon compounds. Organic compounds are essential for life and are found in all living organisms. For example, carbohydrates, proteins, and lipids are organic compounds that are vital for the functioning of the human body. Understanding organic chemistry is crucial for developing new drugs, improving agricultural practices, and creating innovative materials.In addition to the theoretical aspects of chemistry, practical applications are also significant. For instance, analytical chemistry involves the identification and quantification of substances in various samples. This is essential in fields such as forensic science, environmental monitoring, and quality control in industries. Moreover, physical chemistry explores the principles and theories behind the behavior of matter and energy, leading to advancements in fields such as nanotechnology and materials science.In conclusion, chemistry is a diverse and captivating subject that has a profound impact on our daily lives. From understanding the composition of the air we breathe to developing new materials for technology, chemistry plays a crucial role in shaping the world around us.中文：化学是一个迷人的学科，涉及物质及其变化的研究。
与化学有关的英语作文
Chemistry is a fascinating subject that delves into the composition,structure, properties,and reactions of matter.It is a fundamental science that has a profound impact on our daily lives,from the food we eat to the medicines we take,and even the air we breathe.In this essay,we will explore the significance of chemistry,its various branches, and how it shapes our world.The Importance of ChemistryChemistry is often referred to as the central science because of its interdisciplinary nature. It is the study of matter at the molecular and atomic levels,which is crucial for understanding the physical world around us.The principles of chemistry are applied in various industries,including pharmaceuticals,agriculture,materials science,and environmental science.It is also the foundation for many technological advancements, such as the development of new materials,drugs,and energy sources.Branches of ChemistryChemistry is a vast field with numerous branches,each focusing on different aspects of matter.Some of the major branches include:anic Chemistry:This branch deals with the structure,properties,composition, reactions,and synthesis of carboncontaining compounds,which are the basis of life.2.Inorganic Chemistry:It focuses on the properties and behavior of inorganic compounds,which are not carbonbased.This includes metals,minerals,and other noncarbon elements.3.Physical Chemistry:This branch explores the physical properties of substances,such as energy,heat,and light,and how they relate to chemical reactions.4.Analytical Chemistry:It involves the techniques and methods used to determine the composition of substances,including qualitative and quantitative analysis.5.Biochemistry:This is the study of chemical processes within living organisms, including the structure and function of biomolecules like proteins,carbohydrates,lipids, and nucleic acids.6.Environmental Chemistry:This branch examines the chemical and biochemical processes occurring in the environment,including pollution,climate change,and the natural cycles of elements.Chemistry in Daily LifeThe applications of chemistry are ubiquitous.From the synthetic materials used in clothing and electronics to the chemical reactions that produce energy in our bodies, chemistry is integral to our existence.It is also essential in the development of new medicines,which are designed to interact with specific biological targets to treat diseases. The Future of ChemistryAs our understanding of chemistry continues to grow,so does its potential to solve global challenges.For instance,chemists are working on developing sustainable energy sources, such as biofuels and solar cells,to reduce our reliance on fossil fuels.They are also researching ways to mitigate the effects of climate change,such as by creating materials that can capture and store carbon dioxide.In conclusion,chemistry is a dynamic and essential field that underpins many aspects of our lives.Its contributions to science,technology,and society are immeasurable,and its future promises even greater discoveries and innovations.Whether its through the development of new materials,the understanding of life processes,or the quest for a cleaner environment,chemistry will continue to shape our world in profound ways.。
化学论文英文版
化学论文英文版Jun-Ke Wang, Ying-Xiao Zong, Xi-Cun Wang, Yu-Lai Hu, Guo-Ren Yue.Synthesisof N-benzothiazol-2-yl-amides by Pd-catalyzed C(sp2)-H functionalization[J]. CCL, 2015,26(11): 1376-1380Synthesis of N-benzothiazol-2-yl-amides byPd-catalyzed C(sp2)-H functionalizationJun-Ke Wang a,b,c, Ying-Xiao Zong a,b, Xi-Cun Wang a,b, Yu-Lai Hu a,b,Guo-Ren Yue aa Key Laboratory of Hexi Corridor Resources Utilization of Gansu Universities, College of Chemistry and Chemical Engineering, Hexi University, Zhangye 734000, China;b Gansu Key Laboratory of Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, China;c Gansu Engineering Laboratory of Applied Mycology, Hexi University, Zhangye 734000, ChinaReceived 11 May 2015, Received in revised form 29 June 2015, Accepted 1 July 2015,Available online 10 August 2015.E-mail addresses: wangxicun@;huyulai@Abstract: A catalytic synthesis of N-benzothiazol-2-yl-amides from1-acyl-3-(phenyl)thioureas was achieved in the presence of a palladium catalyst through the C(sp2)-H functionalization/C-S bond formation. This synthetic methodology can produce various N-benzothiazol-2-yl-amides in high yields with good functional group tolerance.Key words: Benzothiazole Pd-catalyzed1-Acyl-3-phenylthiourea C-H functionalization L-Proline1. IntroductionThe benzothiazole moiety is an important scaffold due to its widespread occurrence in bioactive natural products,pharmaceuticals, organic optoelectronic materials,and ligands for phosphorescent complexes [1-4]. In particular,substituted Nbenzothiazol- 2-yl-amides are an important class of heterocyclic compounds that exhibit a wide range of biological properties [5-9] such as ubiquitin ligaseinhibition [5],antitumor [6],antirotavirus infections [7],modulating the adenosine receptor [8, 9],and the nuclear hormone receptor [9]. For example,the N-benzothiazol-2- yl-cyclohexanecarboxamide,as a new anticancer drug,was selected as one of the most promising screening hit compounds (Fig. 1) [6]. The acylation reaction from2-aminobenzothiazole,one of the classical methods for the preparation of these molecules [5, 6],is known for the limited diversity of the commercially available starting materials. Furthermore,the preparation of 2-aminobenzothiazole also required the use of the toxic bromine.The past several years have witnessed the great progress in the development of the C-S bond formation promoted by transition metals,which can provide moreefficient,practical,and straightforward approaches to valuable sulfur-containing compounds [10, 11]. However,these methods have been mainly focused on the‘‘traditional’’ cross-coupling reactions of ArX (X = Cl,Br,I,OTf,and B(OH)2) and sulfides [12-39]. To achieve greener and more atomeconomic C-S bond formations,transition metal-catalyzed direct oxidative cross-coupling of C-H bonds and sulfides would be ideal [40-47].In our previous work,we have shown that N-benzothiazol-2-ylamides can be synthesized smoothly by Cu-catalyzed intramolecular cyclization of various substituted 1-acyl-3-(2-bromophenyl) thioureas [48]. This method can provide more diversiform Nbenzothiazol- 2-yl-amides through the carbon-heteroatom formation under relatively mild conditions and avoid the use of the toxic bromine. However,the drawback of this procedure is the limited diversity of the commercially available starting materials due to the use of substituted ortho-haloarylamines. In order to further extend the diversity of N-benzothiazol-2-yl-amides,we have recently demonstrated an efficient intramolecular cyclization of substituted 1-acetyl-3-(2-phenyl)thiourea catalyzed by iron through C-H functionalization [49]. This method can provide more diversiformN-benzothiazol-2-yl-amides under relatively mild conditions. However,the purification of the target compounds is challenging using the column chromatography or recrystallization,since it is inescapable to obtain 1-acetyl-3-phenylurea whose polarity is similar to that of 1-acetyl-3-(2-phenyl)thiourea. Recently,Doi’s group[46] reported a Pd-catalyzed synthesis of 2-substituted benzothiazoles via a C-H Functionalization reaction. Therefore,we envisioned that Pd-catalyzed cyclization of 1-acyl-3-(2-phenyl)- thiourea 1would represent a viable method for the formation and purification of substituted N-benzothiazol-2-yl-amides 2(Scheme 1).2. ExperimentalAll reagents were commercially available and used as supplied. Dimethyl sulfoxide (DMSO) was dried and distilled from calcium hydride. N,N-Dimethylformamide (DMF),toluene,DME and CH3CN were dried prior to use using standard methods. Unless otherwise stated,analytical grade solvents and commercially available reagents were used as received. Thin layer chromatography (TLC) employed glass 0.20 mm silica gel plates. Flash chromatography columns were packed with 200-300 mesh silica gel.All new compounds were characterized by IR,1H NMR,13C NMR and HRMS. The known compounds were characterized by 1H NMR, 13C NMR and HRMS. The IR spectra were run on a Nicolete spectrometer (KBr). The 1H NMR and 13C NMR spectra were recorded on a BRUKER AVANCEIII 400 MHz spectrometer. The chemical shifts (d) were given in parts per million relative to an internal standard tetramethylsilane. High resolution mass spectra (HRMS) were measured with a Waters Micromass GCT instrument and accurate masses were reported for the molecular ion (M+). Melting points were determined on a Perkin-Elmer differential scanning calorimeter and the thermometer was uncorrected.2.1. General procedure for the synthesis of1-acyl-3-arylthioureas [49, 50]To a 25 mL round-bottom flask equipped with a magnetic stirring bar was added acyl chloride (10 mmol),NH4SCN (15 mmol) and CH2Cl2 (20 mL),followed by PEG-400 (0.1 mmol). The mixture was stirred for approximately 3 h at room temperature. Aromatic amine (10 mmol) was added to the mixture and stirred for another 2 h at room temperature. The solvent was removed under reduced pressure to give the resulting residue as a solid,which was washed with water three times,to give the crude product.The analytical samples were obtained by recrystallization from C2H5OH in good yields ([4TD$DIF]88%-98%).2.2. General procedure for the synthesis ofN-benzothiazol-2-ylamides by aPd-catalysed C(sp2)-H functionalization reactionA round-bottom flask equipped with a stirring bar was charged with1-acyl-3-arylthioureas (1 mmol),PdCl2 (10 mol%),CuI (20 mol%),Cs2CO3 (2 equiv.),and L-proline (20 mol%) in 5 mL of DMSO. The mixture was stirred at 100 ℃for the indicated time in Table 2. After cooling to room temperature,the reaction mixture was extracted with ethyl acetate (10 mL × 3). The organic layers were combined,dried over Na2SO4 and concentrated under reduced pressure,and then purified by silica gel chromatography (acetone/petroleum ether = 1:4) to yield the desired product2.N-(4-Ethylbenzo[d]thiazol-2-yl)acetamide (2f): A gray solid (80% yield); mp:264-268 ℃; IR (cm-1): 3169.9,2990.1,2359.9, 1661.1,1550.4; 1H NMR (400MHz,CDCl3): δ 9.42 (s,1H),7.67 (dd, 1H,J = 6.3,2.9 Hz),7.27 (dd,2H,J = 4.4,1.9 Hz),3.04 (q,2H, J = 7.6 Hz),2.28 (s,3H),1.34 (t,3H,J = 7.6 Hz); 13C NMR (100 MHz,CDCl3): δ171.64(s),156.91 (s),146.45 (s),136.81 (s),131.98 (s), 125.25 (s),124.22 (s),118.92 (s),25.36 (s),23.51 (s),14.79 (s); HRMS calcd. for C11H12N2OS [M]+:220.0670; found [5TD$DIF]200.0678.N-(6-Fluorobenzo[d]thiazol-2-yl)acetamide (2 g): A white solid (94% yield); mp:224-231 ℃; IR (cm-1): 3207.8,3071.0,2983.9, 2360.4,1689.2; 1H NMR (400MHz,CDCl3): δ 7.70 (dd,1H,J = 8.9, 4.6 Hz),7.53 (dd,1H,J = 8.0,2.5 Hz),7.19 (td,1H,J = 8.9,2.6 Hz), 2.31 (s,3H); 13C NMR (100 MHz,CDCl3): δ 168.33 (s),160.93 (s), 158.50 (s),121.30 (d,J = 9.1 Hz),114.75 (s),108.09 (s),107.82 (s), 23.46 (s); HRMS calcd. for C9H7FN2OS [M]+: 210.0263; found 210.0256.3. Results and discussionWhile not commercially available,benzothioureas are stable and easilysynthesized [50, 51] from inexpensive starting materials in high yields on a multigram scale. Following Scheme 2,the synthesis of benzothioureas can be achieved in a straightforward manner starting from inexpensive aryl acid chloride and arylamines. Aryl acid chloride was treated with ammonium sulfocyanide in the presence of PEG-400in CH2Cl2,followed by the addition of arylamines,to obtain 1-arylacyl-3-phenylthiourea in good to excellent yields. This intermediate can be used directly without further purifications.In a preliminary experiment,we investigated the intramolecular C-S bond formation of 1-acetyl-3-phenylthiourea utilizing PdCl2 (20%) and a mild base (K2CO3,2 equiv.) in DMSO for 20 h at 100 ℃(Table 1,entry 1). However,the reaction almost failed to take place. Subsequently,we screened several metal salts as cocatalysts, includingAlCl3,CuCl2,Cu(OAc)2,CoCl2,NiCl2,FeCl3,CuI, and CuCl,and found that the addition of CuI considerably enhanced this reaction (Table 1,entries 2-8). However,the desired yield was still not obtained. Surprisingly,when Doi’s condition was used,the yield was still very low (42%) (Table 1,entry 9). Generally,the choice of the ligands is important for the reaction catalyzed by the metal,which prompted us to explore the effect of several bidentate ligands. We carried out the reaction of 1-acetyl-3-phenylthiourea by screening these ligands,such as 1,10-phenanthroline,β-keto esters,β-diketones,andL-proline. (Table 1,entries 10-13),and we were pleased to find that the use of these ligands can notably improve the yield of the product under the same conditions,and that L-proline proved to be the best among an array of ligands tested (Table 1,entry 14). When the amount of CuI and PdCl2 was decreased to 20 mol% and 10mol%,respectively,the catalytic activity was maintained (Table 1,entry 14). Furthermore,we also investigated other bases (Cs2CO3 and K3PO4) (Table 1,entries 15- 16),solvents (DMF,DME,and toluene) (Table 1,entries 17-19) and reaction time (Table 1,entries 20-21). When only CuI was used in this cyclization,no reaction can take place (Table 1,entry 22). Thus, the optimized reaction conditions are as the follows: substrate (1 mmol),PdCl2 (10 mol%),CuI (20 mol%),Cs2CO3 (2 equiv.), L-proline (20 mol%) in DMSO (4 mL) within 8 h at 100 ℃.In response to this encouraging result,we used a range of substituted1-acetyl-3-(phenyl)thioureas to investigate the scope and limitation of this reaction. The corresponding products were obtained in excellent yields (88%-98%). The results obtained under the optimized conditions are listed in Table 2. Initially,the substituents of phenyl were screened. The results demonstrate that little effect of the substituted groups on the benzene ring was observed for this transformation.Furthermore,substituents at different positions of the phenyl ring do not significantly affect the efficiency (Table 2,entries 1-8). It is noteworthy that the halosubstituted benzenes survived leading to halo-substituted products,which can be used for further transformations (Table 2, entries 2,7,8 and 11). In order to make the new Sankyo investigational drugs,the R group was selected as a cyclohexyl to give the corresponding products (Table 2,entries 10-12).Although extensive studies on reaction mechanism have not yet been carried out,the proposed mechanism can be proposed according to the similar palladium-catalyzed processes [51] (Scheme 3). 1-Acetyl-3-(phenyl)thiourea was converted to the thioenolate in the presence of Cs2CO3. Pre-association of the sulphur atom in the thioenolate to Pd(OAc)2 facilitates the orthopalladation process with the concomitant release of chloride ion. The formation of the six-membered palladacycle and the subsequent reductive elimination leads to N-benzothiazol-2-yl-amide and Pd(0). The Pd(0) species are reoxidized to Pd(II) by CuI,thus completing the catalytic cycle.4. ConclusionIn conclusion,we have achieved an efficient intramolecular cyclization of substituted 1-acetyl-3-(2-phenyl) thioureas catalyzed by palladium(II) catalysts through C(sp2)-H functionalization. This method can provide more diversiform N-benzothiazol-2-yl-amides efficiently and quickly in high yields under relatively mild conditions. The combination of the generality with respect to the substrate scope and facile accessibility to the starting materials may generate numerous synthetic possibilities. Further mechanistic analysis of these reactions will be the subject of future work.AcknowledgmentsThis work was supported by the National Natural Science Foundation of China (Nos. 21462016,21262010),Natural Science Foundation of Gansu Province and the Advanced Research Fund of Jinchuan Group Co.,Ltd.References[1] R.S. Keri, M.R. Patil, S.A. Patil, S. Budagumpi, A comprehensive review in currentdevelopments of benzothiazole-based molecules in medicinal chemistry, Eur. J.Med. Chem. 89 (2015) 207-251.[2] A. Rouf, C. Tanyeli, Bioactive thiazole and benzothiazole derivatives, Eur. J. Med.Chem.97 (2015) 911-927.[3] A.G. DiKundar, G.K. Dutta, T.N. Guru Row, S. Patil, Polymorphism inopto-electronic materials with a benzothiazole-fluorene core: a consequence of high conformational flexibility of p-conjugated backbone and alkyl sidechains, Cryst. Growth Des. 11 (2011) 1615-1622.[4] T. Girihar, W. Cho, Y.H. 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化学农业与有机农业英语作文
化学农业与有机农业英语作文（中英文实用版）Chemical agriculture has long been the backbone of large-scale food production, ensuring abundant harvests and reducing the susceptibility of crops to diseases and pests.However, this approach has also raised concerns about environmental pollution, soil degradation, and potential harm to human health.In contrast, organic agriculture promotes a more sustainable and eco-friendly method, strictly prohibiting the use of synthetic fertilizers and pesticides.化学农业长期以来一直是大规模粮食生产的中坚力量，确保了丰收并减少了作物易受疾病和害虫侵害的风险。
然而，这种方法也引发了关于环境污染、土壤退化以及对人类健康潜在危害的关注。
相比之下，有机农业提倡一种更可持续和环保的方法，严格禁止使用合成肥料和农药。
While chemical agriculture may seem efficient in boosting crop yields, it often leads to a dependency on external inputs, which can be costly and environmentally damaging.On the other hand, organic farming relies on natural processes, crop rotation, and the use of organic fertilizers, which enhance soil fertility and biological diversity.尽管化学农业在提高作物产量方面看似高效，但它往往导致对外部投入的依赖，这可能导致成本高昂和环境污染。
有关化学的英语作文
有关化学的英语作文Chemistry, often referred to as the science of matter, is a subject that delves into the composition, structure, and properties of substances. It is a field that has not only contributed significantly to our understanding of the world but also to the development of countless innovations that have transformed our lives.The Building Blocks of ChemistryAt the heart of chemistry lies the periodic table, an organized chart that categorizes elements based on their atomic number, electron configurations, and recurring properties. This table is a chemist's compass, guiding them through the intricate relationships and interactions between elements. From hydrogen to uranium, each element has a unique story to tell, and their combinations give rise to the vast array of compounds that exist.Reactions and TransformationsChemical reactions are the cornerstone of chemistry. They involve the transformation of one set of substances, known as reactants, into another, called products. These reactions can be as simple as the combination of hydrogen and oxygen to form water or as complex as the biochemical reactions that occur within living cells. Understanding these reactions is crucial for creating new materials, medicines, and energysources.The Role of Chemistry in Everyday LifeChemistry is not confined to the laboratory. It is anintegral part of our daily lives. From the plastics and metals we use to the food we eat and the air we breathe, chemistry plays a role. It is involved in the development of fertilizers that increase agricultural yield, the creation of pharmaceuticals that save lives, and the production of cleaner energy sources that combat climate change.The Future of ChemistryAs we look to the future, chemistry continues to be at the forefront of scientific research. With challenges such as sustainable development and disease eradication, the need for chemical innovation is more critical than ever. The development of nanotechnology, the study of materials at the atomic and molecular scale, opens up new possibilities for targeted drug delivery and advanced materials with novel properties.ConclusionChemistry is a subject that bridges the microscopic world of atoms and molecules with the macroscopic world of human experience. It is a field that demands precision, creativity, and a deep understanding of the natural laws that govern our universe. As we continue to unlock the secrets of matter, chemistry will undoubtedly play a pivotal role in shaping thefuture for the betterment of all.In conclusion, chemistry is not just a school subject; it is a powerful tool that helps us understand and manipulate the world around us. It is the science that enables us to transform raw elements into life-saving medicines, to create the technology that connects us, and to find solutions to the pressing issues of our time. As we delve deeper into the atomic realm, the horizon of what is possible expands, and the role of chemistry in our lives becomes ever more significant.。
关于化学的专业英语小作文
关于化学的专业英语小作文Chemistry is a fascinating science that delves into the composition and properties of matter. It is the study of how elements interact and transform, revealing the secrets of the universe at a molecular level.In the realm of chemistry, the periodic table stands as a testament to the systematic organization of elements. Each element has its unique atomic structure, and understanding these structures is key to predicting reactions and behaviors.Experimentation is at the heart of chemistry. It is through the meticulous design and execution of experimentsthat we uncover new compounds, reactions, and insights intothe world of matter. The lab is a place of discovery, where hypotheses are tested and knowledge is expanded.Chemical reactions are the cornerstone of this science. They can be simple or complex, exothermic or endothermic. The balance of reactants and products, governed by the law of conservation of mass, is a fundamental principle that guides our understanding.Analytical chemistry is the branch that focuses on the detection, identification, and quantification of chemical substances. It plays a crucial role in various industries,from pharmaceuticals to environmental monitoring, ensuring safety and quality.Organic chemistry, a sub-discipline, deals with carbon-containing compounds. The complexity of organic molecules and their vast array of reactions make it a rich field for innovation and the development of new materials and drugs.Biochemistry, another branch, explores the chemical processes within living organisms. It is the intersection of biology and chemistry, where the understanding of enzymes, proteins, and metabolic pathways is crucial for advancements in medicine and nutrition.Chemistry education is vital for nurturing the next generation of scientists. It equips students with the analytical skills and knowledge base necessary to contribute to scientific research and technological innovation.In conclusion, chemistry is an ever-evolving field with applications that touch every aspect of our lives. From the medicines we take to the materials we use, the study of chemistry is integral to the progress of human civilization.。
英语选修一第五单元作文有机农业与化学农业
英语选修一第五单元作文有机农业与化学农业全文共6篇示例，供读者参考篇1Farming: Nature's Way or Chemicals Today?Hi there! My name is Jamie and I'm going to tell you all about two different ways of growing food on farms. Some farmers use natural methods that have been around for thousands of years. Other farmers use modern chemicals and technology. Which one is better? Let's take a look!First up, organic farming - that's the natural way. Organic farmers don't use any man-made chemicals like pesticides or fertilizers. Instead, they let nature do its thing! They use natural fertilizers like manure and compost to make the soil healthy. They attract good bugs that eat the bad bugs, so they don't need pesticides. It's like the old days when people just let plants and animals grow naturally.Organic farms have lots of different plants and animals all mixed together. There are fields of crops, but also trees, bushes, ponds, and room for wildlife to live. That's because organic farmers care about the whole environment, not just growing onecrop. The animals like cows, chickens, and pigs can roam around and behave naturally instead of being trapped in tiny cages. Doesn't that sound nice?On the other hand, conventional farms using chemical methods are very different. The fields just have one crop growing, like just corn or just wheat covering hundreds of acres. No other plants are allowed to grow - they are all killed with powerful weed killers. The crops are sprayed with pesticides to kill any bugs or diseases.The farmers also use chemical fertilizers made in factories to make the plants grow big and strong. Without these chemicals, bugs and weeds would take over and the crop wouldn't grow well. It's an endless battle against nature!The animals on these conventional farms live a sad life too. Cows, pigs, and chickens are crammed into barns and cages so tightly. They can barely move around! This allows the farmers to pack in as many animals as possible, but it seems really cruel to the animals.So those are the two main ways of farming today. Which one sounds better to you? I prefer the organic way because it seems so much healthier and nicer for plants, animals, and the whole environment. The chemical way just seems so unnatural andmakes me worried about what those pesticides might do to us when we eat that food. Mmmm, I'll take the fresh organic strawberries over the chemically-grown ones any day!Farmers have a tough job whether they go organic or not. Growing enough food for everyone in the world is hard work! I have a lot of respect for farmers. I just hope more and more will decide to grow food in balance with nature, the way organic farmers do. A world full of organic farms sounds like a healthy, sustainable, and KIND world to me. What do you think? I'd love to hear your perspective!篇2Title: The Battle of the Farms: Organic vs. ChemicalHi there! My name is Emma, and I'm a 10-year-old kid who loves learning about nature and the environment. Today, I want to talk to you about something that's been on my mind a lot lately: organic farming and chemical farming.You see, my family recently decided to start buying more organic fruits and veggies from the local farmer's market. My mom said it's because they're grown without using harmful chemicals called pesticides. At first, I didn't really understandwhat the big deal was, but after doing some research, I realized that this is a pretty important topic that affects us all.Organic farming is a way of growing crops without using synthetic pesticides, fertilizers, or genetically modified organisms (GMOs). Instead, farmers use natural methods like crop rotation, composting, and natural pest control techniques. On the other hand, chemical farming relies heavily on these synthetic chemicals to protect crops from pests and increase yields.Now, I know what you're thinking: "Chemicals? Yuck! Organic must be better, right?" Well, it's not quite that simple. Both methods have their pros and cons, and it's important to understand them before forming an opinion.Let's start with the good stuff about organic farming. First of all, it's better for the environment. Those nasty chemicals used in conventional farming can pollute the soil, water, and air, which is not good for plants, animals, or us humans. Organic farming avoids this pollution and promotes biodiversity by creating a healthier ecosystem for all sorts of critters to thrive.Another great thing about organic farming is that the food it produces is free from synthetic chemicals. This means no pesticide residues on your fruits and veggies, which is especiallyimportant for kids like me whose bodies are still growing and developing.However, organic farming also has some drawbacks. One of the biggest challenges is that it can be more labor-intensive and expensive than conventional farming. Without those powerful chemical pesticides and fertilizers, organic farmers have to work harder to protect their crops and maintain soil fertility. This often results in lower yields and higher prices for organic produce.On the flip side, chemical farming can be more efficient and produce higher yields, which helps feed more people. The use of synthetic pesticides and fertilizers can also make crops more resistant to pests and diseases, reducing the risk of crop failure.But here's the catch: those same chemicals that make chemical farming so productive can also have negative impacts on the environment and human health. Pesticide residues on food have been linked to various health issues, and the runoff from chemical fertilizers can pollute waterways and harm aquatic life.So, what's the solution? Well, in my opinion, the answer lies somewhere in the middle. We can't rely solely on organic farming to feed the world's growing population, but we alsocan't ignore the environmental and health concerns associated with chemical farming.Here's what I think we should do: promote sustainable farming practices that combine the best aspects of both organic and conventional methods. This could involve using natural pest control techniques whenever possible, but judiciously using synthetic pesticides only when absolutely necessary. It could also mean using organic fertilizers and crop rotation to maintain soil fertility, while selectively using synthetic fertilizers to boost yields when needed.Additionally, we should invest more in research and development to create more eco-friendly and effective farming methods. Who knows, maybe one day we'll have super-crops that can resist pests and diseases without any harmful chemicals!At the end of the day, we all play a role in shaping the future of agriculture. As consumers, we can support sustainable farming practices by buying locally grown, eco-friendly produce whenever possible. And as future leaders and decision-makers, we can push for policies and regulations that encourage responsible and sustainable agricultural practices.So, what do you think? Are you team organic or team chemical? Or maybe, like me, you're somewhere in between,hoping for a happy medium that can feed the world while protecting our planet. Whatever your stance, just remember that every little choice we make can have a big impact on the environment and our health.Let's work together to create a future where nutritious, sustainable food is accessible to everyone, and our planet remains a beautiful, thriving home for generations to come.篇3Organic Farming vs Chemical FarmingHi everyone! My name is Emma and I'm 10 years old. Today I want to talk to you about two different ways of growing food - organic farming and chemical farming.Organic farming is a way of growing crops and raising livestock without using man-made chemical fertilizers, pesticides, or other artificial chemicals. The farmers use natural methods instead, like crop rotation, compost, and beneficial insects. Chemical farming is when farmers use those man-made chemicals to help their plants grow bigger and kill bugs and weeds.At first, you might think chemical farming sounds better because the crops grow really big and you get a huge amount of food. But there are actually a lot of problems with using all those chemicals. Let me tell you about some of them.One big issue is that the chemicals can end up in the food we eat and the water we drink, which isn't good for our health. Some of the pesticides have been linked to cancer, birth defects, and other diseases in people. The fertilizers can get washed away by rain into rivers and lakes, causing algae blooms that make the water all green and gross and hurt the fish.The chemicals also kill a lot of the helpful insects and microorganisms that live in the soil naturally. Over time, this can make the soil less fertile and harder for crops to grow in. With organic farming, the soil stays nice and healthy because all the natural processes are working like they're supposed to.Another problem with chemical farming is that a lot of the chemicals get sprayed into the air when they are applied to the fields. This air pollution is bad for the environment and the farm workers who have to breathe it in all day. Some of the pesticides are really toxic and the workers can get sick from too much exposure.What about cost? You might think organic food must be way more expensive than conventional food since it's harder to grow. But part of the higher prices is because organic farmers don't get the same big subsidies from the government that chemical farmers do. If you add in costs like environmental cleanup and health care for exposure to farm chemicals, chemical farming may actually be more expensive overall for society.I could go on, but those are some of the main drawbacks of relying so heavily on chemical farming methods. Does that mean organic is perfect? Of course not - organic farmers still face challenges like droughts, diseases, and insect infestations. But at least with organic you don't have to worry about putting synthetic chemicals directly onto your food and into the environment.In my opinion, the healthier choice is to buy organic fruits and veggies whenever you can. They might not look as big and perfect as chemically-grown produce, but I'd rather have food that is chemical-free and grown in a sustainable way. I'm lucky that my parents buy a lot of our food from the organic section at the grocery store or directly from local organic farms.I hope I've helped explain some of the key differences between organic and chemical farming. It's a complicated issuewithout any simple answers. We need to figure out ways to grow enough food for everyone in the world in an affordable way, but also protect human health and take care of our planet at the same time. I think organic farming is a step in the right direction, but we may need a blend of traditional and modern agriculture methods combined with less food waste to really solve the problem.What do you all think about organic vs chemical farming? I'd love to hear your opinions! No matter what, I'm going to keep learning about this important topic as I get older. Making sure everyone has access to safe, sustainable food is one of the biggest challenges we face. Thanks for listening, guys!篇4Organic Farming vs. Chemical FarmingHi there! My name is Jamie and I'm 10 years old. Today I want to tell you all about the differences between organic farming and chemical farming. It's a really important topic that a lot of grown-ups talk about.Organic farming means farmers grow crops without using synthetic chemicals like pesticides and fertilizers made infactories. Chemical farming is when those artificial chemicals are used. There are some big differences between the two!One of the main differences is how the soil is treated. With organic farming, farmers try to keep the soil healthy by rotating different crops, using natural fertilizers like manure and compost, and avoiding tilling the soil too much. This helps maintain all the good nutrients and microbes in the soil that plants need.But with chemical farming, the soil often gets treated with synthetic fertilizers. These can help plants grow faster in the short-term, but over time they can degrade the soil quality. The soil loses a lot of its natural fertility.Pest and weed control is another big difference. Organic farmers use natural methods like introducing beneficial insects, rotating crops, handpicking pests, and using organic pesticides from things like neem oil and garlic. It's a lot more work!Chemical farmers mainly use synthetic pesticides that kill insects and weeds quickly. While it's more efficient, a lot of those chemicals can linger in the environment and harm other living things too.Then there's the taste and nutrition factor. A lot of people say organic fruits and veggies taste better because the plantsgrow a bit slower and develop more flavor. Some research shows organic food also has more antioxidants and other nutrients.But yields are often lower for organic farming. It's harder work without all those chemicals giving the plants a quick boost. So organic foods usually cost more at the grocery store.There are pros and cons to each approach, but organic farming is generally better for the environment in the long run. It avoids soil depletion and reduces chemical runoff into waterways that can hurt fish and other wildlife.Chemical farming can produce larger yields, but those pesticides and fertilizers hang around and build up over time. They can get into our food chain and potentially cause health issues if we ingest too much.A lot of modern farms actually use a combination of some organic and some chemical practices, trying to find the right balance. But more and more people are choosing organic options when possible to reduce chemical exposure.It's a complex issue and I'm just a kid, but I've learned a ton about it from my parents, teachers, and watching science videos.I hope I was able to explain the basics of organic vs. chemical farming in a way that's easy to understand!Sustainable food production is really important for our future. We have to figure out ways to grow enough food while also taking care of our environment, soil, water, and overall ecosystems. I think organic practices have an important role to play, even if we can't go 100% organic.I'm lucky that my parents buy organic produce as often as they can. To me, organic fruits and veggies just seem to taste better - more flavorful and fresh! I'd way rather have an organic apple than one of those big bright red ones that kind of taste like nothing.My friends and I also like learning about where our food comes from. We think it's really cool that organic farmers work more in harmony with nature instead of just blasting everything with chemicals. It's way more eco-friendly and sustainable.Plus, we feel better knowing we're not ingesting as many pesticide residues in our food. You never know what kind of long-term health effects those chemicals could have, especially for kids whose bodies are still developing.I'm just a fourth grader though, so what do I know? Those are just my thoughts after researching organic vs. conventional farming for a school project. I'll let you grown-ups make up your own minds about this important issue!But I do hope I was able to explain it all in a pretty clear way. Farming and food production can seem like a boring topic for kids, but it's actually fascinating when you start learning about all the different methods and impacts.Thanks for reading my essay! I'm going to go enjoy a snack of organic baby carrots and ranch dip now. I really appreciate farmers who avoid spraying veggies with harsh chemicals. See ya!篇5Farming and Food - The Natural Way or the Chemical Way?Hi there! My name is Billy and I'm in 5th grade. Today I want to talk to you about something really important - farming and how we get our food. You might not think about it much, but the food we eat doesn't just appear in the grocery store out of nowhere! It all starts on farms where things like fruits, veggies, grains and even meat are grown and raised.There are two main ways that farmers can grow crops these days - the organic way or the chemical way. I'm going to explain the differences between them so you can understand which one is better. It's kind of a big deal because the food we eat affectsour health and the health of the planet we live on. Pay attention because this is important stuff!Organic Farming - Nature's WayOrganic farming is the old-school, natural way of growing plants and raising animals for food. Basically, organic farmers work with nature instead of working against it. They use natural fertilizers like manure and compost to feed their plants instead of chemical fertilizers made in factories. Organic farmers also fight pests like insects that might eat their crops using natural methods and ingredients rather than nasty chemical pesticides.One big rule about organic farming is that genetically modified organisms (GMOs) are not allowed. GMOs are plants or animals that have had their genes messed around with in science labs. Their DNA gets mixed with DNA from other plants, animals, bacteria or viruses to try to create something "better". But we don't really know if GMOs are totally safe to eat in the long run. Organic farmers say it's better to stick with good old-fashioned seeds that haven't been genetically modified.With organic farms, the farmers really care about the soil, water, air and all the little critters like worms and bees that help plants grow. They try to work in harmony with the environment and not pollute it with chemicals. Organic farming is kind of likea big circle where nothing goes to waste and everything works together naturally.Here are some other cool things about organic farming:Crops are rotated each season so the same plants aren't grown in the same spot year after year. This helps prevent diseases and pests and makes the soil richer.Animals like chickens and cows are raised in healthier, less cramped conditions without antibiotics or growth hormones.There's usually more variety of crops and animals on an organic farm instead of just one or two main crops. This is better for the environment.Workers on organic farms aren't exposed to harsh chemical pesticides and fertilizers which could make them sick.So in summary, organic farming is the natural, environmentally-friendly way to grow food without messing with nature too much. It's how farming was done for thousands of years before chemical farming came along.Chemical Farming - The Quick Fix?Chemical farming is a more modern way of growing crops that became popular in the last 100 years or so. As the namesuggests, it involves using man-made chemical fertilizers, pesticides, weed killers and other synthetic products to make plants grow bigger and faster.The idea behind chemical farming is to boost crop yields (that means growing way more food than normal). Chemicals like nitrogen, phosphorus and potassium fertilizers are used to pump nutrients into the soil. This forces plants to grow really big really quickly.Pesticides are also sprayed on the crops to kill any insects or critters that might munch on the plants. Some pesticides are made from pretty toxic (poisonous) stuff that can potentially contaminate the soil and waterways around the farm.Another technique in chemical farming is using genetically engineered seeds designed to resist diseases, drought and even the pesticides being sprayed on them! This allows farmers to really douse crops with chemicals without killing the plants themselves.So why do farmers choose to use all these chemicals? Well, for one thing, high crop yields mean more food being produced and more money for farmers. Chemical farming can be very productive and profitable, at least in the short term.It also allows farms to grow the same crops over and over on the same land without rotating fields. And fewer worker hours are required since the chemicals do a lot of the pest control work.But like I said, all these chemicals are really harsh on the environment and could have unknown effects on the plants we eat as well as the people who work on chemical farms exposed to the gases and residues. Not to mention the animals and insects that get wiped out from all the pesticides!Which Way is Better?So those are the two main ways farmers can grow our food these days - chemical farming or organic farming. But which one is the best method?From what I've learned, I think organic farming is the way to go. It treats the environment, soil, plants and animals in a much more natural, sustainable way. The food is grown without any nasty chemicals or genetic modifications that could potentially be harmful to people's health down the road.Organic farms are also usually smaller and better for local communities, providing jobs for workers and delicious, nutritious food for people living nearby. And most importantly, organicfarming protects the planet by avoiding pollution and wasteful practices. If we want to keep the Earth healthy for a long, long time, we need to stop messing with nature so much!Now, I'm not saying chemical farming is 100% bad. Those science-y fertilizers and pest-killing sprays do allow farmers to grow way more crops per acre of land than they could otherwise. This helps provide larger amounts of affordable food for more people around the world.But in my opinion, the benefits of high crop yields from chemical farming don't outweigh the potential environmental damage and health risks. We should be looking for sustainable farming methods that don't sacrifice the planet and ourwell-being just to grow more food more quickly.What's the Solution?The best solution is probably something in the middle - using some modern farming techniques when absolutely necessary, but relying more on organic, earth-friendly practices as much as possible. New technologies could help make organic farming even more efficient and productive too.Governments can support organic farmers by giving them training, subsidies and other incentives to avoid chemicals.Everyday people like you and me can make a difference by buying organic foods whenever we can. If more people demand organic products, more farmers will switch to供给那种方式来留住顾客和赚钱。
有机化学实验 英文
有机化学实验英文Organic Chemistry Experiment.Organic chemistry experiments are an essential part of the study of organic compounds and their properties. These experiments involve the synthesis, purification, and characterization of various organic compounds, as well as the study of their reactivity and behavior under different conditions. Students typically perform a wide range of experiments, including the synthesis of simple organic compounds, the identification of unknown compounds, and the study of organic reactions and mechanisms.In the laboratory, students may be tasked with carrying out procedures such as distillation, extraction, chromatography, and spectroscopic analysis to isolate and characterize organic compounds. They may also explore the principles of organic synthesis by performing reactions such as esterification, Grignard reactions, and Friedel-Crafts alkylation.Furthermore, safety considerations and proper handling of chemicals are important aspects of organic chemistry experiments. Students are expected to adhere to strict safety protocols and use appropriate personal protective equipment to minimize the risk of accidents or exposure to hazardous substances.Overall, organic chemistry experiments provide students with hands-on experience and a deeper understanding of the principles and applications of organic chemistry. Through these experiments, students gain practical skills, develop critical thinking abilities, and learn to apply theoretical knowledge to real-world problems in the field of organic chemistry.。
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有机化学文献简介国外一些科研基金会和统计局调查著名科学家对于科研工作的时间分配, 结果如下: 计划 8 %, 文献查阅51%, 实验 32 %, 编写报告 9 %. 由上面资料可以知道文献资料查阅的重要性.文献按内容区分有一次文献, 二次文献和三次文献. 一次文献即原始文献, 例如期刊, 杂志, 专利等作者直接报导的科研论文. 二次文献指检索一次文献的工具书,例如美国化学文摘及其相关索引. 三次文献为将原始论文数据归纳整理形成的综合资料, 例如综述, 图书, 词典, 百科全书, 手册等.下面简述几种常用的有机化学文献:(一). 三次文献(1). 词典类:i). 英汉,汉英化学化工大词典: 编辑简洁明了, 是查阅化学名词英翻中或中翻英方便省时的工具书. 阅读英文化学书籍或期刊论文, 有些英文单字在一般英文字典查不到, 需要用英汉化学词典, 例如 menthol (薄荷醇); 汉英化学词典在写作英文化学论文时特别需要, 也是出国必备, 例如共轭二烯的英文为 conjugated diene. 较著名的有以下几种版本:a. 英汉,汉英化学化工大词典(学苑出版社): 英汉和汉英分别报导 12万和14万条目.b. 英汉,汉英化学化工词汇(化学工业出版社): 分为英汉和汉英两个单行本, 各报导8万个条目, 携带方便.c. 英汉化学化工词汇(科技出版社): 列出 17 万条目, 报导详尽.ii). 化合物命名词典(上海竹书出版社): 介绍化合物的命名规则, 有 7000 多个例子, 依序报导无机化合物(一元, 二元, 多元化合物, 无机酸和盐, 配位化合物), 有机化合物(脂肪族, 碳环, 杂环, 天然产物以及含各种官能基化合物) 的命名介绍. 每个化合物给结构式及同义词的中英文名字. 例如C6H5OCH3 anisole (茴香醚), methoxybenzene (甲氧基苯), methyl benzyl ether (苯甲醚). 本词典索引齐全, 有分子式索引, 名字索引. 名字索引按照中文笔画排序, 或按照中文或英文拼音排序.(2). 安全手册: 初入实验室的学生以及首次使用某化学品的人员应了解清楚实验所涉及的化学品的性质及其危险指标.i). 常用化学危险物品安全手册(中国医药科技出版社): 报导约 1000种使用, 生产, 运输中最常见的化学药品的安全资料. 报导内容有: 化合物的理化性质, 毒性, 包装运输方法, 防护措施, 泄漏处置, 急救方法(例如皮肤接触溴, 用水冲洗10分钟后再用 2% 碳酸氢钠溶液冲洗; 食入溴立即漱口, 饮用牛奶及蛋清). 本书按照中文笔画排序, 卷末有英文索引, 以及中英对照, 英中对照索引.ii). 化学危险品最新实用手册(中国物资出版社): 报导约 1300 种化学药品的性状(外观, 气味, 熔点, 沸点, 闪点, 密度, 折射率), 危险性(剧毒, 低毒, 致癌, 遇水释放毒气), 禁忌(怕水, 火, 高热), 贮存和运输方式, 泄漏处理, 防护急救措施等.(3). 百科全书, 大全, 手册, 目录i). The Merck Index (默克索引): 是德国 Merck 公司出版的非商业性的化学药品手册, 其自称是“化学品, 药品, 生物试剂百科全书”. 报导1万种常用化学和生物试剂的资料. 描述简洁, 字数数十至数百, 以叙述方式介绍该化合物的物理常数(熔点, 沸点, 闪点, 密度, 折射率, 分子式, 分子量, 比旋光度, 溶解度), 别名, 结构式, 用途, 毒性, 制备方法以及参考文献. 默克索引已经成为介绍有机化合物数据的经典手册, CRC, Aldrich 等手册都引用化合物在默克索引中的编号.书的后半部简单介绍有著名的有机名称反应 (Name Reactions), 例如 acyloin condensation, Knorr pyrrole synthesis, Curtiues rearrangement 等. 书中刊出许多表格, 报导实用资料, 例如缩写, 放射性同位素含量, Merck编号与 CA 登记号的对照表, 重要化学试剂生产公司等. 本书编排按照英文字母排序, 书末有分子式及名字索引.ii). Dictionary of Organic Compounds (有机化合物字典), 简称 DOC, 1934 年首版, 每几年出一修订版, 是有机化学, 生物化学, 药物化学家重要的参考书. 内容和和排版与Merck Index 类似, 但数目多了近十倍, 报导10多万种化合物的资料. 按照英文字母排序, 有许多分册, 刊载化合物的分子式, 分子量, 别名, 理化常数(熔点, 沸点, 密度等), 危险指标, 用途, 参考文献. 因为数目庞大, 另外出版有索引分册, 包括分子式索引(例如C5H13N, 2-Pentylamine, P-00561), CA登记号对照索引(例如60-35-5, acetamide, A-00092), 名字索引(例如Bromoacetic acid, see B-01884).iii). Handbook of Chemistry and Physics (CRC 化学物理手册), 简称 CRC, 是美国化学橡胶公司 (Chemical Rubber Company) 出版的理化手册. 1913 年首版, 目前已出第 79 版本 (1999 年). 早期(例如第63 版) 内容分为6大类, 报导数学用表, 无机, 有机, 普化, 普通物理常数, 及其它. 目前扩充报导14 部, 包括基本常数单位 (section 1), 符号和命名(section 2), 有机 (section 3), 无机 (section 4), 热力学动力学 (section 5), 流体 (section 6), 生化 (section 7), 分析 (section 8) 等. 其中第3部的有机化学报导占 740 页, 用表格很简略的介绍 12000 种化合物的理化资料(例如分子量, 熔点, 沸点, 密度, 折射率, 溶解度), 以及别名, Merck index 编号, CAS 登记号, 及在Beilstein 的参考书目 (Beil. Ref) 等. Beilstein 参考书目的写法早期为 B84, 252, 新版改为 4-08-00-00252, 代表在Beilstein 第4系列(补篇)第8卷252页(新版的 00 表附卷). 化合物的名字排序仿照美国化学文摘, 以母体化合物为主, 例如 p-bromoaniline (对溴苯胺) 查法为 Benzenamine, 4-bromo.紧接着表格, 刊出有以上1万多种化合物的结构式. 本章后面的索引有同义词索引, CAS 登记号索引等.CRC 是个多用途的手册, 其它章节报导有科技名词的定义, 命名规则, 数学公式, 还有许多表格刊载例如蒸汽压, 游离能, 键角键长等有用的资料.早期的 CRC 有机部分有熔点 (-197 - 913 °C) 和沸点索引 (-164 - 891 °C), 可以从熔点沸点数据查出可能的化合物结构. CRC 根据International System of Units, Symbols and Terminology for Physical and Chemical Quantities, Definitions of Scientific Term System 的规定, 列出了书百个国际承认的单位, 符号, 名称的缩写.iv). Lange’s Handbook of Chemistry (兰氏化学手册): 内容和 CRC 类似, 分11章分别报导有机, 无机, 分析, 电化学, 热力学等理化资料. 其中第七章报导有机化学, 刊载7600 种有机化合物的的名称, 分子式, 分子量, 熔点, 沸点, 闪点, 密度, 折射率, 溶解度, 在Beilstein 的参考书目等. 其它章节报导有介电常数, 偶极炬, 核磁氢谱碳谱化学位移, 共沸物的沸点和组成等有用的资料. 本手册有中文翻译本出版.v). Beilstein Handbuch der Organischen Chemie (贝尔斯坦有机化学大全): 简称Beilstein, 为德国化学家 Beilstein 编写, 1882 年首版, 之后由德国化学会编辑, 以德文书写, 是报导有机化合物数据和资料十分权威的巨著. 内容介绍化合物的结构, 理化性质, 衍生物的性质, 鉴定分析方法, 提取纯化或制备方法以及原始参考文献. Beilstein 所报导化合物的制备有许多比原始文献还详尽, 并且更正了原作者的错误. 虽然德文不如英文普遍, 但是许多早期的化学资料仍需借助 Beilstein查询, 加上目前 Beilstein Onlin 网络的流行(价格比 CA 便宜广用), 因此学习和了解 Beilstein 的编辑和使用方法仍是不可免的.Beilstein 目前出版有 7 大系列( H, E I, E II, E III, E III/IV, E IV, E V), 其中 H 表Hauptwerk (正编), E 表 Erganzungswerk (补编). H 系列为基本系列 (Basic Series), 报导1910 年以前的文献资料, 之后每10年增加一个系列(补篇). 后面的补编逐渐采用英文书写. 每个系列有27 卷主卷(其它为索引), 横向分为三大部分: Acyclics (非环系, 1-4 卷), Isocyclics (碳环族, 5-6 卷), Heterocyclics (杂环化合物, 7-27 卷). 按照所具有的官能基纵向依序分为: 无, OH, C=O, CO2H, SO3H, Se, NH2, NHOH, 金属有机等17类; 有 "Table of Contents of the 27 V olumes of the Beilstein Handbook" 帮助了解上述分类. 如果能由分子式索引得到化合物, 便能直接找到其在书卷中的位置. 从 CRC , Lange's Handbook 或 Merck Index 中得到的 Beil. ref 也是捷径, 例子如 B72, 243 代表该化合物出现在 Beilstein 第2 系列(补篇)第7卷243页. Beilstein 的索引不够齐全, 因此查阅资料需要了解其编排方式以判定所查化合物的位置. Beilstein 的编号有一特点, 化合物的卷号可以和其它系列通用. Beilstein 还有主题索引, 比分子式索引实用和广用, 用来查找母体结构化合物.vi). 商用试剂目录: 优点为目录免费索取, 每年更新, 用来查阅化合物的基本数据(分子量, 结构式, 沸点, 熔点, 命名等) 十分方便实用. 这些商用试剂目录大小适中, 在国外实验室人手一册, 被当做化学字典或数据手册使用, 也是很好的化学产品购物指南. 目录中化合物的价格可以做为实验设计的重用参考. 目录中还提供参考文献, 光谱来源, 毒性介绍等. 比较著名的商用试剂目录有以下几种:a. Aldrich: 全名为Aldrich Catalog Handbook of Fine Chemicals,美国 Aldrich 公司出版, 总部设在 Wisconsin 州 Milwarkee. 在美国研究室人手一册. 本目录报导 37000 种化学品的理化常数和价格, 编排简洁. 除了化学试剂, 也刊载和出售各种实验设备例如玻璃仪器, 化学书籍, 仪表等; 有详细附图和功能说明, 是本很好的购物指南, 可以借由图文介绍了解化学仪器的用途或其英文名称.b. Acros: 欧洲出版的试剂目录, 目前在国内流行. 因供货期短 (2-4 周), 订购化合物方便, 供应实验室一些国内买不到的试剂.c. Sigma: 全名为 Sigma Biochemical and Organic Compounds for Research and Diagnostic Clinical Reagents, 主要提供生化试剂产品. 总部在美国 Missouri 州 St. Louis.d. Fulka: 总部在瑞典, Fluka 化学公司. 其产品有些是 Aldrich 找不到的.e. Merck Catalogue: 德国 Merck 公司的商品目录, 包括有 8000 种化学和生物试剂, 及实验设备.(4). 有机化学从书, 实验辅助参考书:i). Organic Reactions (有机反应): 是一套介绍著名有机反应的综述丛书, 1942 年首版, 每1-2 年出版一期, 目前已经 40几期. 每期都会列出以前几期的目录和综合索引. 稿件为特邀稿, 综述介绍一些著名的反应, 题目例如: The Cannizzaro Reaction (2-3, 第二期第三章), The Michael Reaction (10-3), The Beckmann Rearrangement (11-1), The Intramolecular Diels-Alder Reaction (21-1), Reduction with diimide (40-2) 等. 内容描述极为详尽, 包括前言历史介绍, 反应机理, 各种反应类型, 应用范围和限制, 反应条件和操作程序, 总结. 每章有许多表格刊载各种研究过的反应实例, 附有大量的参考文献. 国外有机课程经常以此书做为课外作业, 让学生查阅和描写某反应的内容, 机理和应用范围.ii). Organic Synthesis(有机合成): 是一套详细介绍有机合成反应操作步骤的丛书. 内容可信度极高, 每个反应都经过至少两个实验室重复通过. 最引人入胜的是后面的 Notes, 详细说明操作时应该注意事项及解释为何如此设计, 不当操作可能导致的副产物等. 是本学习搆now how”的反应丛书.iii). Reagents for Organic Synthesis (有机合成试剂): Fieser & Fieser 主编, 1967 年出版的系列丛书, 每 1-2 年出版一期. 其前身是 Expeirments in Organic Chemistry (有机化学实验). 每期介绍这1-2 年期间一些较特殊的化学试剂所涉及的化学反应. 例如Butyllithium, Trifuloroacetic acid, Ferric chloride 或最新发明的试剂. 可以从索引查阅试剂名字, 转而查找其反应应用. 每个反应都有详细的参考书目.iv). V ogel ‘s textbook of Practical Organic Chemistry”, 简称 V ogel. 1948 年首版, 是一本十分实用的反应参考书, 国外每个研究组都有一本置于书架. 可以参考归纳书中介绍的许多类似反应来设计未知的反应条件. 内容主要按照官能团刊载反应. 如同本科生的实验教材一般, 本书对于反应条件和操作程序描述得十分清楚, 有许多反应实例和其参考文献. 书末刊载化合物的理化常数, 和 CRC 等其它化学手册不同的是本书按照官能团排序, 因此能同时列出该化合物衍生物的熔点或沸点数据. 书的前面几章介绍实验操作技术. 附录有各种官能团的光谱介绍, 例如红外吸收位置, 核磁氢谱和碳谱的化学位移等.v). Purification of Laboratory Chemicals (实验室化合物的纯化): Perrin 等主编. 这是实验室中经常使用到的参考书籍. 内容报导各种化合物的纯化方法, 例如重结晶的溶剂选择, 常压和减压蒸馏的沸点, 以及纯化以前的处理手续等. 从粗略纯化到高度纯化都有详细报导, 并附参考文献. 前几章介绍提纯相关技术(重结晶, 干燥, 色谱, 蒸馏, 萃取等), 还有许多实用的表格, 介绍例如干燥剂的性质和使用范围, 不同温度的浴槽的制备, 常用溶剂的沸点及互溶性等资料.vi). Chemical Reviews (化学综述): 美国化学会主办, 1924 年创刊, 一年出版8期, 为特邀稿. 影响因子为17.1, 比一般期刊高近十倍, 可见其受欢迎和重视的程度. 综述文献的优点在于可以从各个角度充分了解报导的专题, 文献后面附有大量的参考文献, 有利于原始资料的查阅. 报导的专题例如: Chromatography (1989), Reactive Intermediate (1991), Boron Chemistry (1992), Photochemistry (1993), Heterogeneous Catalysis (1995), Combinatorial Chemistry (1997). 文章内容包括有前言历史介绍, 各种反应类型及应用, 结论和未来前景.(二). 二次文献:美国化学文摘 (Chemical Abstracts):简称 CA, 美国化学会主办, 1907 年创刊, 是目前报导化学文摘最悠久最齐全的刊物. 报导范围含盖世界160 多个国家 60 多种文字, 17000 多种化学及化学相关期刊的文摘. 每周出版一期,一年共报导70 万条化学文摘, 占全球化学文献的 98 %.每一期按照化学专业分为 5 大部 80 类: 生化 (1-20 类), 有机 (21-34), 大分子 (35-45), 应用化学和化工 (47-64), 物化无机分析 (65-80). 有机部门的例子如物理有机化学 (22), 脂肪族化合物 (23), 脂环族化合物 (24), 多杂原子杂环化合物 (28), 有机金属 (29), 甾族化合物 (32), 氨基酸和蛋白质 (34). 每一期的化学文摘可以当做图书阅读, 例如物理有机或有机金属专业的研究人员, 可以定期阅读每期第22类或29类的文摘, 很容易的便可了解这一周中世界主要化学期刊, 会议录, 科技报告, 学位论文, 新书, 专利(以上为 CA 刊载的刊物类别) 报导这些领域的科研资料.由于文摘数量庞大, CA 设计和出版了许多不同形式的索引, 按照时间区分有期索引(一周), 卷索引(每26期), 累积索引(每10卷, 约5年) 三种; 按照内容区分有关键词索引(keyword index), 作者索引 (author index), 专利索引 (patent index), 主题索引 (subject index), 普通主题索引 (general subject index), 化学物质索引 (chemical substance index), 分子式索引 (formula index), 环系索引 (index of ring system), 登记号索引 (registry number index), 母体化合物索引(parent compound index). 以及索引指南 (index guide), 资料来源索引 (CAS source index) 等. 每种索引的使用方法可以参阅每期, 每卷或每累积本的第一本前面的范例说明.CA 除了做为图书文摘阅读, 其主要功用在于查找文献资料, 例如: 查某个化合物的原始报导(可以从分子式索引, 登记号索引, 环系索引等着手) , 查某个化学反应(化学物质索引), 查某人近年来的科研情形(作者索引), 查某项专利内容(专利索引). 实例如查找对甲苯酚和烯的加成反应: 可以从化学物质索引着手, 找到 p-cresol 后由 reaction 副标题找和烯烃的反应, 得到文摘号后阅读文摘, 如果对内容满意, 由其提供的资料找寻原始文献. 进一步, 得到文章和作者 Saha, M. 后, 可以从作者索引追查其所研究的完整系列.国内目前已从美国化学文摘服务社购入1992 年以后的累积或卷索引及文摘的光盘 (CA on CD), 可以联机检索.(三). 一次文献:(1). 国外化学期刊i). 美国出版的化学期刊a. The Journal of the American Chemical Society (美国化学会志): 简写为J. Am. Chem. Soc., 是目前化学期刊中级别较高的, 影响因子 5.9. 报导综合化学(有机, 无机, 分析, 物化等), 内容有长篇论文和短篇简报 (1-2 页, Communication to the Editors) 各十余篇, 参考文献出现在每页文章下面, 如此著名的期刊到目前却还没有制作图文摘要 (graphic abstract). 在图书馆的摆设, 有些从 J, 有些从 T (例如目前北大图书馆现刊室), 也有些从 A.b. The Journal of Organic Chemistry (有机化学会志), 简写为J. Org. Chem., 美国化学学会主办, 双周刊, 总部在 Ohio State University, 影响因子 3.7. 报导有机和生物有机化学方面的论文, 有长篇的 articles 以及较短篇的 notes 和 communications. 文献题目做成图文摘要 (graphic abstract) 方便了解文章内容.ii). 英国出版的化学期刊:a. Journal of the Chemical Society (英国化学会志), 简称J. Chem. Soc., 英国皇家化学学会主办, 1848 年创刊, 是最老的化学期刊. 1976 年起分成下面几个部分:1.. J. Chem. Soc. Perkin Transactions I: 报导有机和生物有机化学领域的合成反应. 文献内容比较长, 本期刊不接受明显将完整文章分段投稿的情形. 影响因子 1.6.2. J. Chem. Soc. Perkin Transactions II: 物理有机领域, 报导有机, 生物有机, 有机金属化学方面的反应机理, 动力学, 光谱及结构分析等文章. 影响因子 1.7.3. J. Chem. Soc.Faraday Transactions: 物理化学和化学物理领域, 报导动力学, 热力学文章.4. J. Chem. Soc. Dalton Transactions: 无机化学领域.5. J. Chem. Soc. Chemical Communication: 为半月刊, 内容简短, 不超过两页, 没有前言讨论结论, 平铺直叙而简洁的介绍实验新的进展或发现. 影响因子 3.1.b. Tetrahedron (四面体): 1957 年创刊, 半月刊, 有机化学领域, 刊载有机反应, 光谱和天然产物. 影响因子 2.1.c. Tetrahedron Letters (四面体快报): 1959 年创刊, 周刊. 文章内容简洁, 一般2-4 页, 影响因子 2.3. 本期刊和四面体在中国地区的审稿由上海有机所负责. 快报的文章发表后将来可以组合成大文章重新发表.iii). 报导杂环化合物的期刊a. Journal of Heterocyclic Chemistry (杂环化学杂志): 1964 年创刊, 双月刊, 报导杂环化学方面的长篇论文近30 篇, 简讯3-5 篇. 每年的最末期刊出全年的索引, 有作者索引 (author index) 和环系索引 (ring index).b. Heterocycles(杂环化合物): 日本出版, 栏目生动, 有通讯, 论文, 综述, 以及近年新发现的杂环天然产物(分萜, 固醇等6类), 近年进行全合成探讨的天然产物. 后二者并附有期刊出处.iv). 德国出版的化学期刊:a. Synthesis (合成): 以英文书写, 着重反应合成报导, 十分详细, 不乏数十页的文章, 但刊印出来的比较简洁, 只有主要内容大意. 而完整的部分得从微缩胶片调阅, 不另出书. 是本期刊的特点.b. Angewandte Chemie International Edition in English: 1965 年出版, 是德文版 Angewandte Chemie 的英文翻译版, 二者报导的内容相同. 栏目有 reviews, highlight 以及communications.其中 highlight 类似小型综述, 描述某个比较生动的课题. 网络查询, 网址为: www.wiley.vch.de/home/angewandtec. Angewandte Chemie: 内容与栏目和上述的Angew. Chem. Int. Ed. 相同, 只是本期刊以德文出版(但每期偶尔有几篇英文文献). 是用来练习化学德英对照阅读的机会.d. Chemische Berichte (德国化学学报): 1868-1945. 德文书写. 许多早期化学资料仍得从本期刊以及下面介绍的 Ann. 查找.e. Justus Liebigs Annalen der Chemie (利比希化学纪事), 简称 Ann, 1932 年出版, 德文书写, 刊载有机化学与生物有机方面的论文. 目录有英德对照, 论文附有英文摘要.v). 综合科技方面的期刊: 以下两种期刊是所有期刊中级别最高的, 影响因子皆在 20 以上. 虽然只有薄薄几页报导, 但因属于科技的创新(发明或发现), 特别受到重视, 许多作者成为当地具有影响力的学术带头人.a. Science (科学): 美国出版, 影响因子 21.9b. Nature (自然): 英国出版, 1869 年出版, 周刊, 影响因子 27.1(2). 国内化学期刊: 与国外期刊比较, 中国的化学期刊栏目较多而且生动. 比较有名的期刊多由中国化学会, 中科院, 教育部或几所重点学校主办. 目前为 SCI 收录的有化学学报, 中国化学, 高等学校化学学报等. 以英文出版的有中国化学 (Chinese Journal of Chemistry) 和中国化学快报 (Chinese Chemical Letters) 两种. 专门发表有机化学领域论文的有合成化学, 有机化学, 化学通报等. 以下简略介绍国内较著名的化学期刊:i). 上海有机所和中国化学会合办的三种化学期刊: (2000 年开始可以从网络上查阅, 网址为 /publication)a. 有机化学 (Organic Chemistry): 1980 年创刊, 专门报导有机化学领域的论文, 包括有机合成, 生物有机, 物理有机, 天然有机, 金属有机和元素有机等方面. 栏目有长篇的斞芯柯畚臄, 短篇的撗芯客ㄑ稊, 撗芯考虮〝.b. 化学学报 (Acta Chimica Sinica): 刊载综合化学, 包括有机, 无机, 分析, 物化等专业, 栏目有研究专题, 研究论文, 研究简报. 题目附有图文摘要方便了解文章内容. 本期刊为 SCI 收录成为国际核心期刊.c. Chinese Journal of Chemistry(中国化学): 以英文书写, 报导综合化学, 为 SCI 收录. 本期刊原名Acta Chimica Sinica English Edition, 1983 年创刊, 1990 年改成目前名称.ii). 中科院化学所和中国化学会合办的两种化学期刊:a. 化学通报 (Huaxue Tongbao Chemistry): 中科院化学所和中国化学会主办, 1934 年创刊, 月刊, 发表有机化学领域的论文, 栏目有科研与探索, 科研与进展, 实验与教学, 研究快报, 进展评述, 知识介绍. 期刊已上网, 网址为: hppt://b. Chinese Chemical Letters (中国化学快报): 中科院化学所和中国化学会主办, 以英文书写出版, 月刊, 内容简短生动, 2-4 页.iii). 高等学校化学学报 (Chemical Journal of Chinese University): 教育部主办, 吉林大学承办. 1980 年创刊, 月刊. 栏目有研究论文, 研究快报, 研究简报. 每篇文章后面附有英文摘要. 本期刊为 SCI 收录.iv). 北京大学学报 (Acta Scientiarum Naturalium Universitatis Pekinensis) 自然科学版: 北京大学出版, 1955 年创刊, 双月刊. 内容含盖所有自然学科(化学, 物理, 生物, 地质, 数学等). 栏目有长篇论文和研究简报.v). 大学化学 (University Chemistry): 中国化学会和高等学校教育研究中心合办. 栏目有今日化学, 教学研究与改革, 知识介绍, 计算机与化学, 化学实验, 师生笔谈, 自学之友, 化学史, 书评.vi). 合成化学 (Chinese Journal of Synthetic Chemistry): 中科院成都有机所和四川省化工学会主办, 双月刊, 报导有机化学领域论文, 栏目有研究快报, 综述, 研究论文, 研究简报.vii). 应用化学(Chinese Journal of Applied Chemistry): 中国化学会和中科院长春应用化学研究所合办, 1983 年创刊, 双月刊. 内容有研究论文和研究简报, 文章后面附有英文摘要.viii). 化学试剂 (Chemical Reagents): 化工部化学试剂信息站主办, 1979 年创刊. 栏目有研究报告与简报, 专论与综述, 试剂介绍, 分析园地, 经验交流, 生产与提纯技术, 消息.ix). 其它: 化学世界, 化工进展, 精细化工.。