CS208883B1 - Process for preparing cation exchangers from sulfoethylated wood chips - Google Patents

Abstract

The invention provides a method for preparing cation exchangers from sulfoethylated wood sawdust. The essence of the method for preparing cation exchangers from sulfoethylated wood sawdust, from which the water- and alkali-soluble fraction is removed by alkaline extraction, consists in adding an emulsion of epichlorohydrin in sodium hydroxide to the insoluble residue after extraction and, after removing the excess emulsion, crosslinking is carried out at a temperature of 50 to 60 °C for 1 to 1.5 hours, then the product is neutralized with acetic acid, washed with water and dried in air. The use of the invention lies in the fact that this method can be used to dispose of wood waste that arises during mechanical and chemical processing of wood, while obtaining! both soluble derivatives suitable as additives to textile and detergents and cation exchangers with good exchange capacity and stability.

Description

(54) Method for the preparation of cation exchangers from sulfoethylated sawdust

The invention provides a process for the preparation of cation exchangers from sulfoethylated sawdust.

The essence of the process for the preparation of cation exchangers from sulfoethylated sawdust, from which the aqueous and alkali-soluble fraction is removed by alkaline extraction, is to add an emulsion of epichlorohydrin in sodium hydroxide to the insoluble residue and to remove the excess emulsion by crosslinking at 50-60 ° C for 1 to 1.5 hours, then the product is neutralized with acetic acid, washed with water and air dried.

The use of the invention is that wood waste resulting from the mechanical and chemical processing of wood can be disposed of in this way and can be recovered. on the one hand soluble derivatives suitable as additives for textile and laundry detergents and on the other hand cation exchangers with good exchange capacity and stability.

66)

BACKGROUND OF THE INVENTION The present invention relates to a process for the preparation of cation exchangers from sulfoethylated sawdust with a degree of substitution of 0.2 to 0.4.

In particular, cotton, pulp, microcrystalline cellulose, starch and other lignin-free and polysaccharide-containing polysaccharides are used as starting materials for the preparation of sulfoethylated polysaccharides. only in small quantities. If lignified materials are used, water and alkali-soluble fractions are formed during extraction! an insoluble residue that contains a substantial portion of the lignin present, a portion of high molecular weight cellulose, and sulfur within the desired degree of substitution. The insoluble residue exhibits the properties of an acidic ion exchanger having a exchange capacity of 0.5 to 1.5 meq / g. It has the disadvantage of low stability in cycling, as the polymeric components are degraded and lost due to acidic and alkaline action due to dissolution. The proposed procedure addresses how these shortcomings are addressed.

SUMMARY OF THE INVENTION According to the invention, a sulfoethyl derivative is prepared from wood sawdust or lignocellulosic materials formed after hydrolysis of a part of the hemicelluloses, from which the soluble eulfoethylpolysaccharides suitable for detergent and detergent additives are isolated by single or fractional extraction with water and dilute alkali. After removal of the alkaline extract, the insoluble residue is mixed with an emulsion of epichlorohydrin in 0.5% sodium hydroxide using a weight ratio of - insoluble residue: 0.5% sodium hydroxide: epichlorohydrin 10: 40 to 110: 2.5 to 10, for 30 minutes . The excess emulsion is aspirated or centrifuged to 2.5 to 3.5 times the weight of the residue and crosslinking is carried out at temperatures of 50 to 60 ° C for 1 to 1.5 hours. The aspirated emulsion of epichlorohydrin in the diluted liquor can be reused. The resulting cross-linked residue of sulfoethylated sawdust is stable in an alkaline and acidic environment.

An advantage of the proposed process for the preparation of cation exchangers from sulfoethylated sawdust is that:

- all polymeric components of wood sawdust - polysaccharides and lignin are used in this way, which is a rational way of using wood mass,

- represents an epoch of conversion of various plant wastes (sawdust, wood flour, cork pulp, corn cob, etc.) into useful, practically applicable products,

the ion exchanger obtained has an exchange capacity similar to industrial cation exchangers.

Example 1

1.1 kg of air-dry beech sawdust (particle size 0.2 to 4 mm) is sulfoethylated to a sulfur content of 2.5 to 6% and water-alkali-soluble fractions are recovered from the product obtained by extraction with water and dilute alkali solutions in amounts of 0.4 to 4%. 0.7 kg, respectively. 0.35 to 0.25 kg. An insoluble residue after an alkaline extraction step of 0.35 to 0.55 kg a.e. of the substance, untreated after removal of the alkaline extract, is mixed with an emulsion of 0.1 kg of epichlorohydrin in 2.5 L of 0.5% sodium hydroxide for 30 minutes. After removal of excess emulsion by aspiration or centrifugation to a residue weight of 0.9 to 1.9 kg, crosslinking is carried out at 50 to 60 ° C for 1 to 1.5 hours, then the product is neutralized with 10% acetic acid, washed with water and free air dry. 0.5 to 0.5 is obtained

0.7 kg of cross-linked sulfoethyl derivative - cation exchanger having a exchange capacity of 0.5 to 0.8 meq / g and solubility! in 5% sodium hydroxide 2 to 3%.

Example 2

Procedure as in Example 1 except that a mixture of beech and spruce sawdust was used as the starting material, and an emulsion of 0.3 kg of epichlorohydrin in 3 L of 0.5% sodium hydroxide was used for cross-linking. They have a water-soluble and alkali-soluble fraction of sulfoethyl polysaccharides, in amounts of 0.35 to 0.53 kg, respectively. 0.29 to 0.35 kg, 0.4 to 0.55 kg of cross-linked cation exchanger having a exchange capacity of 0.6 to 0.9 meq / g and a solubility in 5% sodium hydroxide is obtained

1.5 - 2 ».

Example 3

Procedure as in Example 1 except that ground lignocellulosic material obtained after hydrolysis of beech sawdust and chips (particle size 0.2-5 mm) is used as starting material and an emulsion of 0.35 kg epichlorohydrin in 4 L is used for cross-linking. 0.5% sodium hydroxide. In addition to 0.32 to 0.5 water-soluble and 0.2 to 0.3 alkali-soluble sulfoethyl polysaccharides, 0.45 to 0.60 kg of cation exchanger are obtained with a exchange capacity of 0.5 to 0.8 meq / g and solubility in 5% sodium hydroxide 0 , 5 to 1%.

The practical importance of the proposed process is that wood wastes in the form of sawdust and flour, which are produced in large quantities in the mechanical and chemical processing of wood, can be disposed of in this way, thereby obtaining both soluble derivatives useful as additives to textile auxiliaries and laundry detergents. cation exchangers with good exchange ·? capacity and stability.

Claims (1)

OBJECT OF THE INVENTION A process for the preparation of cation exchangers from sulfoethylated sawdust from which the aqueous and alkali-soluble fractions are removed by alkaline extraction, characterized in that an emulsion of epichlorohydrin in 0.5% sodium hydroxide is added to the insoluble residue for 30 minutes using an insoluble weight ratio. residue: epichlorohydrin: 0.5% sodium hydroxide 10: 2.5 to 6.0 40 to 110, and after this time, after removal of excess emulsion by suction or centrifugation to 2.5 to 3.5 times the weight of the residue, cross-link at The mixture is neutralized with dilute acetic acid, washed with water and freely dried in air.