CS257486B1 - Method of hydrogen sulphide and carbo disulphide immobilization during cellulose regeneration - Google Patents

Abstract

The method of hydrogen sulfide immobilization and carbon disulphide is to improve work and life environment by significantly reducing concentration toxic and odorous substances in the \ t process. This purpose is achieved by it into the coagulation solution before regeneration cellulose adds hydrogen peroxide in an amount of at least 0.085 g per 1 g of cellulose xanthate solution. A method for immobilizing hydrogen sulfide and carbon disulfide in cellulose regeneration, it is used in organic chemistry, especially in the preparation of microparticulate cellulose.

Description

The invention relates to a method of immobilizing hydrogen sulphide and carbon disulphide in the regeneration of cellulose.

Methods of cellulose regeneration based on coagulation of the xanthate solution and subsequent decomposition to cellulose are known. The most commonly used coagulation solution contains sulfuric acid, sodium sulphate and zinc sulphate (Š. Tomašovič: Fiber manual in the production of viscose fibers, Slovenské nakladatelstvo technickej literaturúry, Bratislava (1960)). The possibility of using other types of acids and their salts, e.g. hydrochloric acid, phosphoric acid, and the like.

During the regeneration of cellulose and concurrent side reactions, volatile toxic substances of hydrogen sulphide and carbon disulphide are released. This is a major drawback in the production of cellulosic materials based on the decomposition of cellulose xanthate. Hermetized fiber. Planters do not solve the limitation of the formation of axhalates, but due to the high concentration of hydrogen sulphide and carbon disulphide in the off-gases, known pollutant trapping methods are applied, either by wet or by adsorption on activated carbon in Lurgi-type plants.

These procedures require high investment and operating costs. Processes for dissolving cellulose in non-aqueous solvents, e.g. paraformaldehyde with dimethylsulfoxide (I. Pekárková, I. Kollár: Chem. fibers 30, 158 (1980)), or a cyclic tertiary amine with dimethylsulfoxide (M. Černochová: Study Report No. 464, p. 48 (1981)). However, both cases also involve the application of toxic substances. Moreover, the cost of said non-aqueous solvents is high.

In addition to the classical use of regenerated cellulose in the form of fibers, irregular or spherical cellulose microparticles, which are usually prepared by acidic or thermal decomposition of a cellulose xanthate solution, have been widely used in recent years. Lurgi-type devices for preparing microparticulate cellulose have not yet been designed. To date, cellulose has not been regenerated from a solution of cellulose xanthate in the presence of hydrogen peroxide.

These disadvantages are substantially eliminated by the method of immobilization of hydrogen sulfide and carbon disulphide in the regeneration of cellulose in cellulose xanthate solutions, which comprises adding to the coagulation solution at least 0.085 g per 1 g of cellulose xanthate solution prior to regeneration.

The advantage of the proposed method of immobilization of hydrogen sulphide and carbon disulphide in the regeneration of cellulose from the cellulose xanthate solution over the prior art processes is that this will prevent the escape of volatile, odorous, toxic substances from the system and thereby protect workers health, improve work and environment and increase Safety at Work.

• Oxidation of hydrogen sulphide and carbon disulphide produces non-volatile substances that remain in the coagulation system. The application of the method of immobilization of hydrogen sulfide and carbon disulphide according to the invention for the production of fiber, where the fiber withdrawal velocities are of the order of 1.5 ms at low reaction temperature, viscosity 18 ° C and spinning bath 45 ° C, short-term interaction of hydrogen peroxide with fiber deep destruction of regenerated cellulose.

Particularly preferred is the proposed method of immobilizing hydrogen sulphide and carbon disulphide in the preparation of microparticulate cellulose for sorption purposes, where the possible oxidation and reduction of the polymerization degree of cellulose during regeneration are not impeded.

EXAMPLE

The coagulation solution contains 200 ml of water, 20 ml of 96 wt. sulfuric acid and 40 ml of 32 vol. hydrogen peroxide. After adding 5 g of a cellulose xanthate solution containing 8 Ϊ cellulose, 6 wt. % sodium hydroxide and 2.67 wt. a mixture of hydrogen sulfide and carbon disulphide in a ratio of 1: 5, cellulose is regenerated.

At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. The concentration of carbon disulphide and hydrogen sulphide was calculated after 0.010 mg.m \

Example 2

The procedure is as in the example, except that the coagulation solution constitutes 200 ml of 32 vol. hydrogen peroxide. Addition of 5 g of a cellulose xanthate solution having the properties of Example 1 regenerates the cellulose. A sample is taken at a height of 15 mm above the surface and analyzed by gas chromatography. The concentration of hydrogen sulfide and carbon disulfide was 33 after conversion of 0.008 mg.m.

Example 3

The procedure is as in Example 1 except that the coagulation solution is composed of 200 ml of water, 20 ml of 85 wt. phosphoric acid and 60 ml of 32 vol. hydrogen peroxide.

Addition of 5 g of a cellulose xanthate solution having the properties of Example 1 regenerates the cellulose. At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. The concentration of hydrogen sulfide and carbon disulfide after recalculation was 0.012 mg.m.

Example 4

One liter of coagulation solution contains 90 g of 96 wt. sulfuric acid, 220 g of sodium sulphate, 60 g of zinc sulphate and 240 ml of 32% vol. hydrogen peroxide. Addition of 5 g of a cellulose xynthogenate solution having the properties of Example 1 results in regeneration of the cellulose. At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. The concentration of carbon disulfide and hydrogen sulphide was 0.011 mg.m.

Example 5

The coagulation solution contains 200 ml of water, 20 g of citric acid and 40 ml of 32 vol. hydrogen peroxide. After adding 5 g of a cellulose xanthate solution having the properties as in Example 1, the cellulose is regenerated. At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. Concentration of hydrogen sulphide after conversion of 0,02 mg.m \

Example 6

The coagulation solution is composed of 100 ml of 96 vol. ethanol and 70 ml of 32 vol. hydrogen peroxide. To this mixture is added 5 g of a cellulose xanthate solution having the properties of Example 1. Cellulose regeneration occurs. At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. The concentration of hydrogen sulfide and carbon disulphide was --3 after conversion of 0.007 mg.m.

Example

Up to 50 ml 24 wt. Sodium bisulfite solution was added with 60 ml of 32 vol. hydrogen peroxide. 5 g of a cellulose xanthate solution having the properties of Example 1 are added to the coagulation solution thus prepared. Cellulose regeneration takes place. At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. The concentration of hydrogen sulfide and carbon disulfide was 0.0008 mg.m.

Example 8

The coagulation solution is composed of 100 ml of 40 wt. ammonium sulfate. 10 g of a 4.25 wt. peroxidu.vodíka. A 5 g solution of cellulose xanthate having the properties of Example 1 was added to the mixture. At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. The concentration of hydrogen sulfide and carbon disulfide was 0.02 mg.m.

To compare the effects of the previously known coagulation solution compositions used in the regeneration of cellulose from cellulose xanthate solutions with the method proposed by us, the following example is given:

Example 9

The procedure is as in Example 4 except that the coagulation solution does not contain hydrogen peroxide. after the addition of a 5 g solution of cellulose xanthate having the properties of Example 1, the cellulose is regenerated. At a height of 15 mm above the surface, a sample was taken and analyzed by gas chromatography. The concentration of hydrogen sulphide and carbon disulphide was 485 mg.m.

The method of immobilizing hydrogen sulfide and carbon disulfide can find wide application in organic chemistry and in manufacturing based on the regeneration of cellulose from cellulose xanthate solutions.

Claims (1)

Method for immobilizing hydrogen sulphide and carbon disulphide in regenerating cellulose with coagulation solutions from a cellulose xanthate solution, characterized in that hydrogen peroxide is added to the coagulation solution prior to regeneration in an amount of at least 0.085 g per 1 g cellulose xanthate solution.