CS224909B1 - The preparation of the o-/3-chlorine-2-hydroxypropyl/-cellulose - Google Patents

Description

The present invention relates to a novel process for the preparation of O- (3-chloro-2-hydroxypropyl) cellulose. ^{224 909}

O- (3-Chloro-2-4-hydroxypropyl) -cellulose is an important reactive cellulose derivative suitable for many other transformations. to a certain degree of dried cellulose with chloromethyloxirane (epichlorohydrin) under catalysis with Lewis or Bronsted acids. High.Soledin.8, 1450 (1966): P. Gemeiner and J. Zemek: Collect. Czech.Chem.Cemmun.46.

1693 (1931), boron trifluoride etherate (J. Ellingboe, Blllme and J. Sovali; Acta chem.Scand. 24, 463 (1970): P. Gemeiner and J. Zemek; Collect.Czeeh. Commun. 46, 1693 (1981). perchloric acid and hydrogen chloride (P. Geemeiner, PV 3476-81). In the last two cases, when spherical macroporous cellulose was used, a product with a smaller specific surface area than the starting cellulose was produced. This was due to irreversible changes due to the "dry" drying of the cellulose. In addition, the addition of the catalyst often resulted in localized mineralization of the sample resulting in a non-homogeneous product.

The proposed procedure eliminates the shortcomings of the known methods. SUMMARY OF THE INVENTION The present invention is characterized in that wet activated cellulose dried by liquid exchange for 1,4-dioxane or dry cellulose is reacted in a 1,4-dioxane suspension with chloromethyloxirane under the catalytic action of perchloric acid in the presence of water at a temperature of 90 to 100 ° C. for 2 to 4 hours at molar ratios of cellulose / anhydroglucose unit /: chloromethyloxirane: chloroacetic acid: water 1: 3 to 20: 0.05 to 0.7: 5 to 20. The 0/3-chloro-2-hydroxypropyl formed The cellulose, which is isolated from the reaction mixture by filtration and washing the solid phase with alcohol and water, virtually completely retains the porosity or degree of swelling of the starting cellulose.

An advantage of the proposed process for the preparation of O- (3-chloro-2-hydroxypropyl) cellulose, which has been developed primarily for the modification of macroporous spherical cellulose, is that the starting cellulose does not need to be dried in the low-liquid state. A further advantage of the present method is that it is applicable to tubular cellulose: spherical, fibrous and powdered materials, both in the dry state and to swelling-activated preparations. The presence of an inert solvent will additionally heat the cellulose prior to mineralization

- υ224 909 of the catalyst and ensures its more homogeneous distribution in the reaction medium. However, the most important advantage is that spherical O- (3-chloro-2-hydroxypropyl) cellulose prepared in this manner, unlike the same derivative prepared by a dry process, retains the porosity of the starting spherical cellulose at the same degree of substitution.

Example 1

The aspirated spherical cellulose (10 g; 15.0% dry matter) was washed with methanol (5x5 mL) and dioxane (5x5 mL). Dioxane (15 ml), water (0.75 ml) and a solution prepared by mixing chloromethyloxirane (7.2 ml) and a mixture (3.75 ml) of 70% perchloric acid and dioxane 1: 9 ( The reaction mixture was heated at 97 ° C for 4 hours. Finally, the solid phase was aspirated and washed with methanol (5 x 5 mL) and water (5 x 5 mL). White spherical O- (3-chloro-2-hydroxypropyl) cellulose (9.7 g; 17.9% dry matter, 5.1% chlorine, (degree of substitution by chlorohydroxypropyl groups) 0.27) was obtained.

Example 2

The aspirated spherical cellulose (6 g; 15.0% dry matter) was taken up in dioxane and aspirated according to the procedure of Example 1.

Water (0.9 ml) was added to the aspirated cellulose and, after mixing, a solution prepared by mixing chloromethyloxirane (4.5 ml) and a mixture (0.5 ml) of 70% perchloric acid and dioxane 1: 19 (v / v) ). The reaction mixture was heated at 97 ° C for 4 hours. After aspirating the solid phase and washing it with methanol and water, spherical O- (3-chloro-2-hydroxypropyl) cellulose (6.1 g; 16.7% dry matter, 4.6% chlorine, SS _CHp 0.24) was obtained.

Example 3

Viscose staple (1 g) was mixed with dioxane (20 ml), water (1 ml) and a solution prepared by mixing chloromethyloxirane (10 ml) and a mixture (5 ml) of 70% perchloric acid and dioxane 1: 9 (v / v) ). The reaction mixture was heated at 95 ° C for 4 hours. The solid was then filtered off, washed with methanol (3 x 25 mL) and dried from ether to give

-3ι224 909 white fibrous O- (3-chloro-2-hydroxypropyl) cellulose (1.1 g;

2.3% chlorine, SS _CHp 0.11).

Example 4

The viscose staple (2 g) was mixed with 17% aqueous sodium hydroxide (50 ml) and allowed to stand under nitrogen at 5 ° C for 1 hour. The mixture was neutralized with 10% aqueous acetic acid, filtered off with suction and washed with methanol (3 x 50 ml). Extracted activated staple from dioxane was treated exactly according to the procedure of Example 3, i.e. in this case half the amount of chloromethyloxirane and the other components of the reaction mixture to cellulose was used as compared to the procedure of Example 3. White fibrous O- (3-chloro-2-hydroxypropyl) cellulose (2.4 g; 7.6% chlorine, SS _CHp 0.43) was obtained.

Example 5

The cross-linked microcrystalline cellulose (4 g) was activated with sodium hydroxide solution according to the procedure of Example 4 and the silane was then treated exactly as described in Example 3, i. in this case, a quarter of the amount of chloromethyloxirane and the other components of the cellulose reaction mixture was used as compared to Example 3. A white cross-linked microcrystalline O- (3-chloro-2-hydroxypropyl) cellulose (5.1 g; 9.6% chlorine, SSf = 0.50) was obtained.

O- (3-Chloro-2-hydroxypropyl) cellulose is insoluble ♦

in water and conventional organic solvents and gives reactions of cellulose, alkyl halides and halohydrins, wherein the derivatives prepared in this way contain 40 to 60% halohydrin groups.

The invention has utility in organic synthesis in the preparation of an important intermediate, O- (3-chloro-2-hydroxypropyl) cellulose for the preparation of a wide variety of cellulose derivatives for use in organic chemistry, biochemistry and biotechnology.

Claims (1)

-1 /. OBJECT OF THE INVENTION 224 909 Process for preparing O- (3-chloro-2-hydroxypropyl) cellulose by treating with chloromethyloxirane under the catalytic action of perchloric acid in the presence of water at elevated temperature, characterized in that wet activated cellulose dried by liquid exchange with 1,4-dioxane or dry cellulose is reacted in 1,4-dioxane slurry at 90 to 100 ° C for 2 to 4 hours at molar ratios of cellulose reactants (: chloromethyloxirane: perchloric acid: water 1: 3 to 20: 0.05 to 0.7: 5 to 20 wherein the O- (3-chloro-2-hydroxypropyl) cellulose, which is isolated from the reaction mixture by filtration and washing the solid phase with alcoholons and water, has the same degree of swelling or porosity as the starting cellulose ·