CS221024B1 - Process for preparing benzaldehyde cellulose derivatives - Google Patents

Abstract

The invention relates to a method for preparing benzaldehyde derivatives of celluloses. The essence of the invention lies in the fact that aminocellulose is allowed to react with p-isothiocyanate benzaldehyde at a temperature of 20 to 40 °C for 2 to 8 hours in a reaction mixture of a buffer solution and a water-miscible solvent, preferably dioxane, in the pH range of 4 to 8. The invention is useful in the preparation of activated matrices for immobilization of biochemicals with applications in the field of enzyme engineering.

Description

221024

The present invention relates to a process for the preparation of benzaldehyde cellulose derivatives. Polysaccharides containing carbonyl groups are often used as carriers for the preparation of immobilized enzymes. One possibility of preparing such polyaldehydes is by bonding the carbonyl group via a reaction of the bifunctional aliphatic carboxylate compound with a suitable matrix. The glutaraldehyde reaction with aminocelluloses is most often used [A.F.A.Habeeb: Arch. Biochem. Biophys; 19, 264 (1977), K. Das et al., Biochim. Biophys. Acta 397,277 (1975)].

A disadvantage of this process for the preparation of aldehyde derivatives is the entry of both carbonyl groups into reactions with cellulose amino groups (cross-linking), which on the one hand decreases the functional groups of the modified celluloses and, on the other hand, it is essential to change the properties of the starting celluloses. The second possibility of introducing carbonyl group into the cellulose chain is the periodate oxidation of cellulose or oxidation with bromine water to form the so-called periodic oxidation of the cellulose chain. cellulose dialdehydes [E. Brown, A. Ra-cois; Tetrahedron Lett., 5077 (1972)].

However, this method, which has been used up to now, causes cellulose structure defects and the maximum aldehyde content is about 0.1 mmol / g cellulose. Similar possibilities for immobilizing enzymes offer celluloses with aromatic carbonyl groups that have not been used for this purpose. The preparation of such cellulose derivatives can be carried out in a similar manner to the preparation of carriers with aliphatic aldehyde groups, i.e. by reaction of a suitable matrix with a bifunctional, in this case an aromatic aldehyde.

The above drawbacks are substantially obviated by the process for the preparation of benzaldehyde cellulose derivatives, the principle of which is that the aminocellulose is reacted with the p-isothiocyanatobenzaldehyde of the color:

R-NHZ + SCN - O-CHQ

R-NH-C-NH CHO where R-NH2 is an amino cellulose, at molar ratios of the amino group of the aminocellulose: p-isothiocyanatobenzaldehyde 1: 3 at 2 ° C to 40 ° C for 2 to 8 hrs in the 2-Amino-2- buffer reaction mixture hydroxymethyl-1,3-propanediol hydrochloride and water-miscible solvent: dioxane in the pH range of 4 to 8.

The described process provides a simple preparation of new benzaldehyde derivatives of celluloses. Its advantage is the possibility to prepare modified cellulose with high content of carbonyl groups without visible change in the structure of starting celluloses. The advantage of the proposed process is that a new type of cellulose derivative is obtained, and tobenzaldehyde derivatives, which have a similar wide application as starting amino derivatives, make it possible to achieve complete conversion of amino groups to aldehyde groups; The starting amino derivatives are either available or can be readily prepared [A. L. Bullock, J. D. Guthrie: Methods in Carbohydrate Chemistry (R. L. Whistler): Vol. V, Academic Press, New York, London, 409 (1965)]. Said process allows the use of spit celluloses, for example powdered, pearled spherical, with different amino groups. It also provides for the preparation of benzaldehyde cellulose derivatives with targeted contents of benzaldehyde groups and their skeletons. The best results were obtained by the powdered aminoethylcellulose in neutral or neutral. a slightly alkaline medium (pH 7 and pH 8 respectively) with a 100% conversion rate and a content of 0.8 mmol aldehyde groups / g. Example 1g of 1-amino-amino groups / g of aminoethylcellulose was suspended in 40 ml of a mixture composed of a buffer of 2-amino-2-hydroxymethyl-1,3-propanediol hydrochloride (0.2 mole / l) and 1: 1 dioxane, the pH of which was adjusted to 7 and the temperature was 20 ° C. 0.4 g of β-isothiocyanatobenzaldehyde is added to the slurry after stirring for 4 h. The reaction product (0.96 g) is filtered off, washed 5 times successively with a buffer of dioxane buffer, sodium chloride solution at a concentration of 1 mol. ≪ tb > ______________________________________ < tb > ______________________________________ < tb > ______________________________________ < tb > ______________________________________ < tb > example of valence vibrations of carbonyl

Procedure as in Example 1 except that aminoethylcellulose was suspended in a 2-Amino-2-hydroxymethyl-1,3-propanediol hydrochloride (0.2 mol / l) mixture of dioxane 1: 1 with pH adjusted to 8 and it is stirred for 2 h at 40 ° C. The resulting product (0.95 g) contains 2.7% sulfur and 0.78 titratable aldehyde groups / g.

Claims (2)

The product spectrum shows a strong absorption band in the region of 1700 cm -1. EXAMPLE 3 Procedure as in Example 1, except that the aminethyl cellulose is suspended in a buffer solution. 2-Amino-2-hydroxymethyl-1,3-propanediol hydrochloride (0.2 mol / l) and dioxane 1: 1 with pH adjusted to 4 and stirred for 8 h. ) contains 0.4% sulfur and 0.11 mmol of titratable aldehydes / g. In the IR spectrum, there is a 1700 cm-1 weak intensity. EXAMPLE 4 Procedure as in Example 1 except that 10.7 g of aspirated, ie dry, pearl aminoethylcellulose (0.3 mmol of amino groups / g), 20 ml of buffer solution 2 - Amino-2- are used. hydroxymethyl 1,3-propanediol hydrochloride (0.2 mol -1) and dioxane 1: 1 and aspirated product (6.0 g) is maintained in water at 4 ° C. The reaction product contains 2.0% nitrogen and 0.25 mmol titratable aldehyde / g. The sample porosity as measured by the centrifugation method is 85 ° / o. The IR spectrum showed at 1700 cm @ -1. EXAMPLE 5 Procedure as in Example 1 except that 9.3 g of aspirated (2.6 g dry) pearl aminodeoxycellulose (0.31 mmol amino groups / g) and 20 ml of 2-Amino buffer solution are used -2-hydroxymethyl-1,3-propane-diol hydrochloride (0.2 mol -1) and dioxane 1: 1. The product (7.0 g after aspiration) contains 1.2% nitrogen and 0.225 mmol tritrovaldehyde. The sample porosity is 84%. A band at 1700 cm -1 is located in the IR spectra. Example 6 Procedure as in Example 1 except that 2.6 g of sucked (0.6 g dry) pearl aminohexyl cellulose (1.26 mmol amino groups / g) is used. ) and 20 ml of 2-Amino-hydroxymethyl-1,3-propanediol hydrochloride buffer solution (0.2 moles -1) and dioxane 1: 1. 5 ° / nitrogen and 0.13 mmol titratable aldehyde / g. The sample porosity is 84%. The IR spectrum shows a weak band at 1700 cm -1. Example 7 Procedure as in Example 1 except that 1.8 g aspirated (0.5 g dry) pearl p-aminophenyl cellulose (1.75 mmol / g) are used 20 ml of a mixture of 2-amino-2-hydroxymethyl-1,3-propanediol hydrochloride buffer (0.2 mol -1) and dioxane1: 1. The product (1.4 g after aspiration) contains 4.9% nitrogen and 0.215 mmol of titratable aldehydes / g. Product porosity is 85 ° / o. The IR spectrum shows a band at 1700 cm’1. The invention has utility in the preparation of activated matrices for the immobilization of biochemicals by application in all areas of enzyme engineering, as well as a reactive product for the preparation of other type-activated matrices with the same utility in the isolation of low molecular weight compounds. OBJECT OF THE PREPARATION A method of preparing benzaldehyde cellulose derivatives, characterized in that the amidocellulose is reacted with β-isothiocyanatobenzaldehyde at a molar ratio of amino to cellulose: β-isothiocyanato tobenzaldehyde 1: 3 at 20 to 40 ° C. for 2 to 8 hours in a reaction mixture of a buffer of 2-amino-2-hydroxymethyl-1,3-propanediol hydrochloride and water-miscible solvent, preferably dioxane, in the pH range of 4 to 8.