The invention relates to the oxidation of cellulose and cellulose derivatives using nitrosonium ions

The invention relates to the oxidation of cellulose and cellulose derivatives using nitrosonium ions (oxoammonium ions) obtained by oxidation of nitroxyl radicals, especially

2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO).

A process in which TEMPO is reoxidised by chemical means is known from a review by De Nooy in Synthesis 1996, 1153-1174 and from WO 95/07303.

The oxidation of cellulose to 6-aldehydo-cellulose by photolysis of

6-azido-6-deoxy-celluloses was reported by Horton et al. Carbohydrate Research, 26 (1973) 1-19.

It was found according to the invention that oxidation of cellulose, especially cellulose fibres, using nitrosonium ions, can be carried out without using chlorine-based oxidising agents and with the use of hydrogen peroxide or oxygen as the ultimate oxidising agent. The oxidation according to the invention is performed using enzymes capable of oxidation or transition complexes of a transition metal and a complexing agent as intermediate oxidants. This oxidation results in the formation of cellulose 6-aldehydes. The aldehydes may be present in the (hemi)acetal form and related structures. The process of the invention is further defined by the characterising features of the appending claims.

In the following description, reference is made to TEMPO only for the sake of simplicity, but it should be understood that other suitable nitroxyls, i.e. organic nitroxyl compounds lacking .alpha.-hydrogen atoms, such as 2,2,5,5-tetramethylpyrrolidine-N-oxyl (PROXYL), 4-hydroxy-TEMPO,

4-acetamido-TEMPO and derivatives thereof and those described in WO

95/07303 can be substituted for TEMPO. These di-tert-alkyl nitroxyls are especially suitable for selectively oxidising primary alcohols to aldehyde functions, in particular in the presence of secondary alcohol functions that should not be oxidised. Less sterically hindered nitroxyls, such as 4,4-dimethyloxazolidine-N-oxyl (DOXYL), are suitable for preferentially oxidising secondary alcohols to keto functions, for example in the production of keto cellulose or keto starch. The active oxidising species is the nitrosonium ion (oxoammonium ion>N.sup.+.dbd.O), that is produced in situ by oxidation of the corresponding hydroxylamine and nitroxyl radical. If desired, the reaction can be performed in two steps, the production of the nitrosonium ion being the first and the oxidation of the alcohol function being the second.

A catalytic amount of nitroxyl is preferably 0.1-25% by weight, based on the primary alcohol functions of the cellulose, or 0.1-25 mol % with respect to the primary alcohol. The nitroxyl may also be immobilised, e.g.

by coupling of the hydroxyl group of 4-hydroxy-TEMPO to a suitable carrier, or in the form of a polymeric nitroxyl such as: --[(CH.sub.3).sub.2

C--NO.--C(CH.sub.3).sub.2 --A--].sub.n --, wherein A may be an alkylene group and/or a heteroatom, and n is a number form e.g. 10 up to several hundreds.

The process of the invention results in oxidation of cellulosic anhydroglucose units to the corresponding aldehydes. If required the primary products can be further oxidised to the corresponding carboxylic acids by using known oxidising agents such as hypochlorite, chlorite, hydrogen peroxide or by using TEMPO-mediated oxidation under more vigorous conditions such as an increased temperature e.g. from

40-80.degree. C., or for prolonged exposure to the reaction conditions. Alternatively, the aldehyde/carboxylic acid ratio can be increased by using relative low pH's (e.g. pH 3-7), by controlled addition of oxidising agent, by lowering the oxygen concentration, or by first preparing the nitrosonium ion solution (two-step process).

A distinct group of compounds suitable for oxidation with the present process consists of hydroxyalkylated cellulose such as hydroxypropyl cellulose, hydroxyethyl cellulose.

The oxidation of the primary alcohol functions (6-CH.sub.2 OH) results in the corresponding aldehydes and, if desired, to carboxylic acids, with intact ring systems. These products are useful intermediates for functional cellulose derivatives wherein the aldehyde groups are further reacted with e.g. amine compounds and the like. They are also useful intermediates for crosslinked cellulose derivatives, in which the aldehyde groups are further reacted with e.g. diamine reagents.

The catalysts to be used according to the invention are complexes of transition metals, i.e. coordination compounds between a transition metal and an organic molecule as a complexing agent having one or more free electron pairs, especially nitrogen compounds. Suitable nitrogen compounds include amino acids, phenanthrolines and other polyamines. A polyamine, which forms a complex with the transition metal, is understood to refer to compounds which comprise at least two amine nitrogen atoms, separated by at least two carbon atoms. Preferably, the polyamines comprise at least three nitrogen atoms which in each case are separated by two or more, in particular two or three, more in particular two, carbon atoms. The remaining valencies of the nitrogen atoms are preferably bound with small alkyl groups, in particular methyl. It is also possible for the polyamines to have ether or alcohol functions. The polyamines can be linear or cyclic. The polyamines should be alkaline, i.e. should not

contain acid functions. Examples of polyamines which can be employed are 2,2'-bipyridyl, 2,2'-bipyrrole, 2-(dimethylaminomethyl)pyridine, tetramethylethylenediamine, pentamethyl-diethylenetriamine,

1,4-dimethylpiperazine, 1,4,7-trimethyl-1,4,7-triazonane

(=triaza-cyclonanane), 1,4,7-trimethyl-1,4,7-triazecane,

1,4,7,10-tetramethyl-1,4,7,10-tetraaza-cyclododecane,

1,2-bis(4-methyl-1-piperazinyl)ethane,

1,2-bis(4,7-dimethyl-1,4,7-triazonan-1-yl)ethane, and the corresponding compounds wherein one or more of the said methyl groups have been replaced by, for example, ethyl groups. It is also possible to use porphin and other porphyrins and corresponding macrocyclic polyamine compounds. Histidine and comparable amino acids having an additional nitrogen atom, and their oligopeptides such as histidyl-histidine, are other examples of suitable complexing agents. Preference is given to compounds of the bipyridyl type, triazonane type and to amines whose remaining valencies are linked to methyl groups. The counterions required for neutrality of the complexes may be common, preferably non-toxic counterions such as oxide, halide, perchlorate, acetylacetonate, nitrate, sulphate and the like.

Transition metals to be used in the metal complexes include especially those of the fourth period of the periodic table of elements from vanadium to zinc, preferably manganese, iron, cobalt, nickel and copper, in particular manganese, iron, cobalt and copper. The corresponding metals from the higher periods may also be used, although less preferentially. The metal complexes require hydrogen peroxide, alkyl and ar(alk)yl hydroperoxides (such as tert-butyl hydroperoxide), oxygen or chlorite as an ultimate electron acceptor. About one metal atom to two to four nitrogen atoms of the compelling agent can suitably be used.

The metal complex may be used in a catalytic amount, e.g. in about an equimolar amount with respect to the nitroxyl compound. Suitable amounts of metal complexes are for example 1-25 mol % with respect to the alcohol to be oxidised.

The catalysts to be used according to the invention can also be oxidoreductases or other enzymes that are capable of oxidation in the presence of a suitable redox system. Oxidoreductases, i.e. enzymes capable of oxidation without the presence of further redox systems, to be used in the process of the invention include peroxidases and oxidases, in particular polyphenol oxidases and laccase.

Peroxidases (EC 1.11.1.1-1.11.1.11) that can be used according to the invention include the peroxidases which are cofactor-independent, in

particular the classical peroxidases (EC 1.11.1.7). Peroxidases can be derived from any source, including plants, bacteria, filamentous and other fungi and yeasts. Examples are horse-radish peroxidase, soy-hull peroxidase, myeloperoxidase, lactoperoxidase, Arthromyces and Coprinus peroxidases. Several peroxidases are commercially available. The peroxidases require hydrogen peroxide as an electron acceptor.

Polyphenol oxidases (EC 1.10.3.1) include tyrosinases and catechol oxidases, such as lignine peroxidase. Suitable polyphenol oxidases may be obtained from fungi, plants or animals. The polyphenol oxidases require oxygen as an electron acceptor. Laccases (EC 1.10.3.2) are sometimes grouped under the polyphenol oxidases, but they can also be classified as a distinct group, sometimes referred to as p-diphenol oxidases. Laccases can be derived from plant sources or from microbial, especially fungal, sources, e.g. of the species Trametes versicolor. The laccases also require oxygen as an electron acceptor.

The process of the invention can be performed under relatively mild conditions, e.g. at a pH between 5 and 10, and at a temperature between 15 and 60.degree. C. (both depending on the particular metal complex or enzyme). The reaction medium can be an aqueous medium, or a homogeneous mixed medium, e.g. of a mixture of water and a secondary or tertiary alcohol or an ether/water mixture, or a heterogeneous medium, e.g. a mixture of water and a water-immiscible organic solvent such as a hydrophobic ether, a hydrocarbon or a halogenated hydrocarbon. In the latter case, the metal complex or enzyme and/or the nitroxyl and the oxidising agent may be present in the aqueous phase and the alcohol substrate and the aldehyde or ketone product may be present in the organic phase. If necessary, a phase transfer catalyst may be used. The reaction medium can also be a solid/liquid mixture, in particular when the nitroxyl is immobilised on a solid carrier. A heterogeneous reaction medium may be advantageous when the substrate or the product is relatively sensitive or when separation of the product from the other reagents may present difficulties.

The invention also pertains to novel cellulose oxidation products and derivatives thereof, which can be obtained with the process of the invention. These include cellulose in which at least 1 hydroxymethyl per 100, especially per 50 or even per 25, monosaccharide units has been converted to a carbaldehyde group, whether or not in hemiacetal or similar form, with the proviso that on average each molecule contains at least 1 carbaldehyde group other than a possible (hemiacetalised) aldehyde group at the reducing end of an oligo- or polysaccharide, in addition to at least 1 hydroxymethyl group per 100 being oxidised to a carboxyl group.

The products obtainable according to the invention may contain, in addition to the aldehyde groups, other functional groups, especially carboxyl groups obtained by further oxidation or by carboxyalkylation.

The novel derivatives of the invention are very suitable as wet strength additives, water-absorbing polymers and the like, and especially as starting materials for further functionalisation, especially with alcohols, amines, and other agents capable of coupling with an aldehyde function. Such agents include crosslinking agents (diamines, diols and the like), which can be used to crosslink the cellulose derivatives or to couple them to amino acids, proteins, active groups etc.

The invention also pertains to derivatives obtained by coupling of the aldehyde cellulose derivatives described above with e.g. amines, especially by reductive amination, to produce imino or amino derivatives of cellulose as defined in the appending claims. Also, the aldehyde cellulose derivatives can be reacted acetalised with

hydroxy-functionalised compounds, e.g. glycolic acid, for further derivatisation.

The oxidation of cellulose and its derivatives according to the invention results in the presence of both aldehyde groups and carboxyl groups in the product. The process is especially useful for oxidising cellulose fibres, as the resulting oxidised fibres have improved wet strength properties for paper and tissue applications. The process is also useful for oxidising cellulose to produce a water-absorbing cellulosic material, if desired after further oxidation or carboxymethylation or other derivatisation of the product.

EXAMPLES

General

Uronic acid (6-COOH of hexopyranose units) contents were determined using the Blumenkrantz et al. method (Anal. Biochem. 54, (1973) 484). The method was adapted as follows. 5 ml of sample is suspended in water. 20 ml of a solution of boric acid (0.0125 M) in concentrated (95-97%) sulphuric acid is added. The final volume (V) is made up to 25 ml. 0.2 ml of this solution is added to 0.2 ml of pure water and then 1.0 ml of the sulphuric acid boric acid reagent is added. This solution is heated at 100.degree.

C. during 5 minutes. After cooling in ice 20 .mu.l of an aqueous solution of 3-hydroxy-biphenyl (0.2% w/w) is added, upon which a pink colour develops. After 15 minutes incubation the extinction is measured at 520 nm. The calibration curve is based on D-glucuronic acid as a reference

material.

Aldehyde contents were determined either by a subtractive method (determining the uronic acid content before and after of oxidation of aldehydes with chlorite and hydrogen peroxide), or by addition of hydroxylamine hydrochloride to produce an oxime and back-titration of liberated hydrochloric acid, or by .sup.13 C NMR spectroscopy (intensity of C6 signal of aldehyde with respect to C1 of anhydroglucose unit, or intensity of C6 (C.dbd.N) in the oxime).

Example 1

Production of 6-aldehyde Cellulose

One gram of totally chlorine-free bleached and sheet-dried kraft pulp (Grapho Celeste), dry weight oven dried) was suspended in 100 ml of water. To this suspension were added 18 mg of TEMPO (0.1 mmol) and 9 mg of peroxidase (HRPO), type VI (290 units/mg). The pH was adjusted to 5.1 with aqueous acetic acid (0.1 M). A hydrogen peroxide solution (1.5 ml 30% in 50 ml) was added stepwise (30-50 .mu.l every 2 minutes) for 8 hours. After peroxide addition the pH decreased, but it returned to its original value (5.5) after a few minutes; therefore, no pH adjustment was necessary during the reaction. After 21 h a sample was analysed by addition of hydroxyl-ammonium chloride and titrated with aqueous sodium hdyroxide (0.1 M). According to this analysis, the sample contained 160 micromol C6-aldehyde per g cellulose.

Example 2

Oxidation of Cellulose with Laccase

To 2 g of cellulose fibres, activated by treatment with sodium hydroxide solution and water, 17 mg recombinant Trametes versicolor laccase (Wacker Chemie) was added. The solution (pH between 6.0 and 5.1) was exposed to oxygen in a closed system so that the consumption of oxygen could be measured by a gas burette as a function of time. The consumption of oxygen after one day reaction was 20 ml (0.8 mmol). As a second step 0.2 ml hydrogen peroxide (30% w/w) and 250 mg sodium chlorite (Aldrich, 80%) were added to the reaction mixture. After standing for one day at pH 4-4.5, an almost homogeneous mixture was obtained, from which samples were withdrawn. The uronic acid content of the whole reaction mixture was determined. According to the adapted Blumenkrantz method the content was 0.7 mmol, which gives 350 mmol/g.

Example 3

Oxidation of Cellulose Fibres

To 2 gram cellulose fibers (the same as in Example 1) suspended in 25 ml water, 28 mg of horse radish peroxidase (HRP, Sigma), 20 mg TEMPO were added. The pH of the mixture was brought to 5.3 and then 1 mmol of hydrogen peroxide solution (5 ml 0.6%, w/w) was added in 100 .mu.l portions in the course of 3 hours. Despite the relatively quick addition, gas (oxygen) evolution was hardly visible. According to the Blumenkrantz method the yield of uronic acid was 9%. This example illustrates the influence of rate of hydrogen peroxide addition which was fast compared to example 1, resulting in relatively high levels of carboxylic acid

Example 4

Oxidation of Cellulose Fibres with Oxygen Catalysed by Copper/bipyridine.

1 gram cellulose fibres (CTMP) were suspended in 50 ml water. Then 10 ml of a 5% (w/w) TEMPO solution, 0.4 ml of a solution of copper nitrate (0.4M) and 10 ml of a bipyridine solution (0.05M) were added. Through the stirred solution oxygen gas was bubbled. After one day the fibres were collected by filtration, washed repeatedly with water and dried in vacuum. The uronic acid content (adapted Blumenkrantz) of the dried fibres was 9%.

Example 5

Production of 6-aldehyde-6-carboxy Cellulose

Production of 6-aldehyde-6-carboxy cellulose. One gram of totally chlorine-free bleached and sheet-dried kraft pulp (Grapho Celeste), dry weight oven-dried) was suspended in 20 ml of water. To this suspension were added 20 mg of TEMPO (0.1 mmol) and 19 mg of peroxidase (HRPO), type VI (290 units/mg). The pH was adjusted to 5.5 with aqueous acetic acid (0.1 M). A hydrogen peroxide solution (1.2 ml 3%) was added stepwise (50 ml every 10 minutes) for 6 hours. After 21 h a sample was analysed by addition of hydroxylammonium chloride and titrated with aqueous sodium hydroxide (0.05 M). According to this analysis, the sample contained 300 micromol C6-aldehyde per g cellulose. In addition it was found that the sample contains uronic acid (100 micromol per g).

* * * * *

该发明涉及氧化纤维素和纤维素衍生物使用nitrosonium离子（离子oxoammonium ）获得了氧化硝基自由基，尤其是2,2,6,6 ， tetramethylpiperidin - 1 -氧自由基（天霸）。

在这一进程中天霸reoxidised是通过化学手段是从审查的德Nooy在1996年合成， 1153年至1174年，从沃07303分之95 。

氧化纤维素至6醛纤维素的光6叠氮- 6 -脱氧-细胞所报告的霍顿等人。碳水化合物的研究，26 （ 1973 ） 1-19 。

这是根据发现的发明，它的氧化纤维素，特别是纤维素纤维，采用nitrosonium离子，可进行不使用氯的氧化制剂和使用的氧气或过氧化氢作为最终氧化代理人。氧化根据发明是用酶能够氧化或过渡金属配合物的一个过渡和络合剂作为中间氧化剂。这种氧化的结果形成的纤维素6醛。该醛可能是目前在（半）缩醛形式和相关结构。这一进程的发明是进一步界定characterising功能附加要求。

在下面的描述，提到了天霸不仅是为了简单，但它应该认识到，其他合适的nitroxyls ，即硝基有机化合物缺乏。 alpha.氢原子，如2,2,5,5 ， tetramethylpyrrolidine氮氧自由基（ PROXYL ）， 4 -羟基节奏， 4 -乙酰氨基节奏和衍生物和所描述的那些窝95 / 07303可取代的速度。这些二叔烷基nitroxyls是特别适合小学选择性氧化为乙醛醇职能，特别是在中学的存在酒精职能，不应当氧化。减体阻碍nitroxyls ，如4,4 - dimethyloxazolidine 氮氧自由基（ DOXYL ），适合中学择优氧化醇至酮的功能，例如在生产酮酮淀粉或纤维素。积极氧化物种是nitrosonium离子（ oxoammonium离子“ N.sup 。 + 。 Dbd.O ），这是就地生产氧化相应的硝基自由基和盐酸。如果想要的话，反应可以在两个步骤，生产的nitrosonium离子的第一和氧化的功能正在饮酒的第二次。

催化数额硝基最好0.1-25 ％，按重量计算的基础上，主要职能纤维素酒精，或0.1-25 ％，摩尔对主要酒类。对硝基也可能是车窗，例如耦合的羟基 4 -羟基节奏，以一个合适的载体，或在形式的高分子硝基如： -[ （ C H.sub.3）。 s ub.2C组- c否. - - （ CH.sub.3 ）。Sub.2 -阿- ]。 S u b.n-，其中甲可能是亚烃基组和/或杂原子，和n是一个数字的形式如10个多达数百人。

这一进程的发明成果中的氧化纤维素anhydroglucose单位相应的醛。如果需要的初级产品，还可以进一步氧化相应的羧酸用已知的氧化制剂，如次氯酸钠，绿泥石，过氧化氢或使用天霸介导的氧化下更加有力的条件，如增加温度如从40 80.degree 。角，或长期暴露在反应条件。另外，醛/酸比可提高用相对低pH值的（如pH值3-7 ），除了控制剂的氧化，降低氧浓度，或编写了第一份nitrosonium离子溶液（两个步骤）。

一个单独组的化合物氧化适合本过程包括hydroxyalkylated羟丙基纤维素，如纤维素，羟

乙基纤维素。

氧化的主要职能酒精（ 6 CH.sub.2俄亥俄州）的结果在相应的醛，如果想要，以羧酸，完整的环形系统。这些产品是有用的中间体功能纤维素衍生物，其中醛群体正在进一步反应，例如：胺化合物等。他们也有用的中间体交联纤维素衍生物，其中醛群体正在进一步反应，例如：试剂二胺。

该催化剂用于根据发明的复合过渡金属，即之间的协调过渡金属化合物和有机分子作为络合剂有一个或多个自由电子对，尤其是氮的化合物。适用于含氮化合物包括氨基酸，及其他多胺菲。阿多胺，形成一个复杂的过渡金属，被理解为是指化合物，其中包括至少两个氨基氮原子，失散至少有两个碳原子。最好的多胺包括至少三个氮原子在每一种情况下是分开由两个或两个以上，尤其是两个或三个，另外两个特别是碳原子。其余的价态的氮原子是最好的约束与小烷基群体，特别是甲基。这也是有可能的多胺有酒精或醚的职能。该多胺可线性或循环。该多胺应碱性，即不应含有酸性的职能。多胺的例子可雇用的2,2 ' -吡啶， 2,2 ' - bipyrrole ， 2 -（ d imethylaminomethyl）吡啶， t etramethylethylenediamine， p entamethyl胺- 1 .4- d imethylpiperazine， 1 ,4,7-三甲基- 1 ,4,7 - Triazonane （ = triaza - cyclonanane ）， 1,4,7 -三甲基- 1 ,4,7 - triazecane ， 1,4,7,10 -甲基- 1 ,4,7,10 -四氮杂cyclododecane ， 1,2 -二（ 4 -甲基- 1 -哌嗪基）伊桑， 1,2 -二（ 4,7 -二甲基- 1 ,4,7 - TRIAZONE - 1 -基）伊桑，以及相应的化合物，其中一人或更多的说，甲基组已被取代，例如，乙团体。它也可以使用卟吩和其他卟啉和多胺相应的环化合物。组氨酸和可比的氨基酸有一个额外的氮原子，它们的肽，如histidyl -组氨酸，其他一些例子合适的络合剂。优先考虑的化合物类型的吡啶， triazonane胺型，其剩余的价态都与甲基组。该counterions所需的中立性，复杂的可能是共同的，最好是无毒的counterions 如锈病，哈利德，氯酸盐，乙酰丙酮，硝酸盐，硫酸盐等。

过渡金属，用于金属配合物包括特别是第四期间的元素周期表从钒锌，最好锰，铁，钴，镍，铜，特别是锰，铁，钴和铜。相应的金属从较高的时期也可使用，但不到优先。该金属配合物的要求过氧化氢，烷基和河（碱）基过氧化氢（如叔丁基过氧化氢），氧或绿泥石作为最终电子受体。大约有金属原子以2至4个氮原子的令人信服的代理人可以适当使用。

该金属配合物可用于催化剂的金额，如在大约一个equimolar数额方面的硝基化合物。适合大量的金属配合物是例如1-25 ％，摩尔对酒精的氧化。

该催化剂用于根据发明也可以氧化还原酶或其他酶，能够氧化存在一个合适的氧化还原系统。氧化还原酶，即酶氧化能力不在场的情况下进一步氧化还原系统，将使用过程中的发明包括氧化酶和过氧化物酶，尤其是多酚氧化酶和虫。

过氧化物酶（欧共体 1.11.1.1-1.11.1.11 ），可根据发明包括过氧化物酶的辅助因子独立，特别是古典过氧化物酶（欧共体 1.11.1.7 ）。过氧化物酶可以来自任何资料来源，包括植物，细菌，和其他丝状真菌和酵母菌。例子有辣根过氧化物酶，氨壳过氧化物酶，髓过氧化物酶，乳过氧化物酶和过氧化物酶Arthromyces鸡腿。过氧化物是几点商用。需要的过氧化物酶过氧化氢作为电子受体。

多酚氧化酶（欧共体 1.10.3.1 ），包括酪氨酸和儿茶酚氧化酶，如木素过氧化物酶。合适

的多酚氧化酶可从真菌，植物或动物。多酚氧化酶的需要氧作为电子受体。 Lacco （欧共体1.10.3.2 ），有时归入多酚氧化酶，但他们也可以被列为一个独特的群体，有时也称为对苯二酚氧化。 Lacco可从植物源或从微生物，特别是真菌，来源，例如：物种变色栓菌。该虫也需要氧作为电子受体。

这一进程的发明可以下进行相对温和的条件下，如pH值在5至10个，并在一个温度在15至60.degree 。角（均根据具体金属配合物或酶）。反应介质可以是水溶液中，或均匀混合媒介，例如一个混合水和二级或三级酒精或醚/水混合物，或非均匀介质，例如混合的水和水混溶的有机溶剂，如疏水乙醚，碳氢或卤化烃。在后一种情况下，金属配合物或酶和/或硝基和氧化代理人可能存在的水相和酒精基板和醛或酮的产品可能存在的有机相。如有必要，相转移催化剂可用于。反应介质也可以是固体/液体混合物，特别是当硝基车窗上了坚实的载体。异质反应介质可能是有利的基板时，或产品是比较敏感或离职时，该产品从其他试剂可目前的困难。

这项发明还涉及到新型纤维素的氧化产物和衍生物，可取得的过程中发明的。这些措施包括纤维素，其中至少有1每羟甲100个，特别是每50或什至每25个单糖单位已转化为甲醛组，不论是否在hemiacetals或类似的形式，条件是平均每个分子包含至少一日甲醛集团以外的其他可能（ hemiacetalised ）醛减少组在结束了寡或多糖，此外，至少有1每100 HYDROXYMET HYL组被氧化为羧基。该产品根据获得的发明可能包含，除醛团体，其他功能的群体，尤其是羧基得到了进一步的氧化或carboxyalkylation 。

新颖的衍生产品的发明非常适合作为添加剂的湿强度，吸水性聚合物等，尤其是作为起始原料为进一步functionalisation ，特别是与醇，胺，和其他代理人能够耦合与醛功能。这些代理商包括交联剂（二胺二醇等），可以用来交联纤维素衍生物或夫妇他们氨基酸，蛋白质，活跃的群体，等等。

这项发明还涉及到衍生产品获得了耦合的醛纤维素衍生物与上文所述例如胺，尤其是还原氨化，生产氨基酸亚或其衍生物的纤维素中所界定的附加要求。此外，纤维素衍生物醛可以反应acetalised羟基functionalised化合物，例如乙醇酸，为进一步derivatisation 。

氧化纤维素及其衍生物根据发明成果都存在醛团体和羧基的产品。这个过程是特别有用的氧化纤维素纤维，因为由此产生的氧化纤维改善了湿强度性能的纸张和组织的应用。这个过程也是有用的氧化纤维素生产吸水性纤维材料，如果需要经过进一步的氧化或羧甲基化或其他derivatisation的产品。

实例

一般

糖醛酸（ 6 -羧基的hexopyranose单位）含量使用Blumenkrantz等。法（ Anal.生物化学。 54 （ 1973 ） 484 ）。该法调整如下。 5毫升的样品已暂停在水中。二十零毫升解决的硼酸（ 0.0125男）在集中（ 95-97 ％），硫酸增加。最后卷（五）是多达25毫升。 0.2毫升这个解决办法是增加至0.2毫升的纯净水然后1.0毫升的硫酸试剂硼酸增加。这种解决办法是加热100.degree 。角在5分钟。冷却后冰20 。 Mu.l的水溶液3 -羟基联苯（ 0.2 ％瓦特/瓦特）是说，在一个粉红色的发展。 15分钟后孵化灭绝测量520纳米。校

准曲线是基于D -葡萄糖醛酸作为参考材料。

醛含量也由消减法（确定糖醛酸含量之前和之后的氧化醛与绿泥石和过氧化氢），或加入盐酸羟胺产生肟和后备滴定解放盐酸，或由。 sup.13核磁共振光谱（强度信号的C6醛方面的C1的anhydroglucose单位，或强度的C6 （ C.dbd.N ）在肟）。

范例1

生产的6 -醛纤维素

一克完全无氯表干燥和漂白硫酸盐浆（图塞莱斯特），干重焦炉干）是悬浮在100毫升的水。为此暂停了18毫克的天霸（ 0.1毫摩尔）和9毫克的过氧化物酶（结合物），第六型（ 290单位/毫克）。 pH值调整为5.1的醋酸水溶液（ 0.1米）。阿过氧化氢溶液（ 1.5毫升30 ％， 50毫升）是逐步增加（ 30-50 。 Mu.l每2分钟） 8小时。过氧化氢后此外， pH 值下降，但它返回其原来的价值（ 5.5 ）几分钟后，因此没有pH值的调整是必要的反应。经过二一公顷样品分析是由另外的羟基氯化铵和滴定与水钠hdyroxide （ 0.1华氏度）。根据这一分析，样本包含160 micromoles每件C6 -醛克纤维素。

示例2

氧化纤维素的Lacco

2克纤维素纤维，活化治疗的氢氧化钠溶液和水， 17毫克重组变色栓菌虫（瓦克化学）增加。该解决方案（ pH值6.0至5.1 ）暴露于氧气在一个封闭的系统，使消费的氧气可以衡量的天然气滴管作为时间函数。消费的氧气后，一天的反应是20毫升（ 0.8毫摩尔）。作为第二步0.2毫升过氧化氢（ 30 ％瓦特/ w ）和250毫克亚氯酸钠（奥尔德里奇， 80 ％）被加入反应混合物。经过长期的一天在pH值4-4.5 ，几乎均匀混合物获得，从样品被撤回。该糖醛酸含量的整个反应混合物决心。根据该方法适应Blumenkrantz的内容是0.7毫摩尔，使350毫摩尔/克

范例3

氧化纤维素纤维

为了2克纤维素纤维（一样的范例1 ）悬浮在25毫升水， 28毫克的辣根过氧化物酶（辣根过氧化物酶）， 20毫克天霸又增加了。 pH值的混合物被带到5.3 ，然后一毫摩尔过氧化氢溶液（ 5毫升0.6 ％瓦特/ W型）增加了100 。 Mu.l部分过程中的3个小时。尽管相对快速此外，气体（氧气）的演变几乎清晰可见。据Blumenkrantz方法的糖醛酸产量的9 ％。这个例子说明了影响率除过氧化氢是比较快的例子1 ，造成相对较高的羧酸

示例4

氧化纤维素纤维与氧催化的铜/吡啶。

1克纤维素纤维（化学热磨机械浆）被暂停在50毫升的水。然后一十毫升的5 ％（瓦特/瓦特）天霸的解决方案， 0.4毫升的解决铜硝酸盐（ 0.4米）和10毫升的一个解决办法吡啶（ 0.05M ）又增加了。通过搅拌的解决办法是氧气气泡。经过一天的纤维所收集过滤，反复洗涤水和真空干燥。糖醛酸的含量（改编Blumenkrantz ）的干燥纤维9 ％。

例5

生产的6 -醛- 6 -羧基纤维素

生产的6 -醛- 6 -羧基纤维素。一克完全无氯表干燥和漂白硫酸盐浆（图塞莱斯特），干重焦炉干）被禁赛20毫升的水。为此暂停增加了20毫克的天霸（ 0.1毫摩尔）和19毫克的过氧化物酶（结合物），第六型（ 290单位/毫克）。 pH值调整为5.5乙酸水溶液（ 0.1米）。阿过氧化氢溶液（ 1.2毫升3 ％）逐步增加（ 50毫升每10分钟一班）为6小时。经过二一公顷样品分析是由另外的羟胺和滴定氯与氢氧化钠水溶液（ 0.05女）。根据这一分析，样本包含300 micromoles每件C6 -醛克纤维素。此外，发现样本含有糖醛酸（ 100 micromoles 每克）。