SU423807A1 - METHOD OF OBTAINING AMPHOTERIC IONITE - Google Patents

Description

one

The invention relates to the field of producing amphoteric cellulose derivatives, ion exchangers containing both acidic and basic groups.

A very promising type of ion-exchange materials are cellulose derivatives, which are obtained from available raw materials in a simple manner and have a fibrous character, which accounts for a number of their advantages.

A method is known for producing an amphoteric ion exchanger by oxidizing cellulose and then treating it with a mixture of o-toluenesulfonyl chloride. However, since the ion exchanger does not contain strongly acidic groups, it cannot be used in a strongly acidic environment. Its other drawback is insufficient chemical resistance, which is typical of oxidized cellulose.

The purpose of this invention is the synthesis of cellulose-based ampholyte containing strongly acidic groups.

The proposed method consists in pre-phosphorylating cellulose, and then treating the resulting phosphate cellulose with a mixture of o-toluenesulfonyl chloride and pyridine.

Ampholyte exchange capacity, mgEq / g:

acid group (Ca2 +) 1.68

by main group (by OH-ions) 1.41

In addition, the possibility of using ampolpta to extract metal ions from solutions of complex composition was tested. So, at pH 3-4, sorption of the main groups of molybdenum (VI) is observed, in the form of Mo7O24, equal to 140 mg / g, and sorption of acid groups as. Equal to 74 mg / g. When this is achieved 99.8% recovery of molybdenum from solution.

Example 1. A portion of cellulose (5 g) is treated with an aqueous solution of o-phosphoric acid and urea (starting from a ratio of 4 mol of urea per 1 mol of o-phosphoric acid) for 30 mpn at room temperature, drained, dried at 60 ° C. It is then heated to 135 ° C for 30 minutes, the product is washed with hot, cold water and dried at 60 ° C. The obtained sample is dehydrated in several portions of pyridine. The sample is treated with a mixture of 50 g of o-toluenesulfonyl chloride in 100 ml of pyridine for 10 hours at room temperature, and then heated in pyridine at a temperature of 80 ° C for 10 hours.

Wash off with alcohol and water. The content of phosphate groups,% 2,48

Nitrogen content,% 0.78

Exchange capacity for acid

groups, mEq / g1,67

Exchange capacity by major

groups, mEq / g0.94

Example 2. Obtaining phosphate cellulose, as in example 1. The sample is treated with a mixture of 75 g of o-toluensulfonyl chloride in 100 ml of pyridine for 10 hours at room temperature. Then heated in pyridine for 10 hours at 115 ° C. The content of phosphate groups,% 3,11

Content of nitrogen,% 1Д7

Exchange capacity for acid groups, mEq / g2,24

Exchange capacity by major groups, mg-eq / g1.87

Subject invention

The method of obtaining amphoteric ion exchangers by introducing acidic groups into cellulose, followed by treatment with a mixture of o-toluenesulfonyl chloride and pyridine, characterized in that, in order to increase thermal and chemical stability and expand areas of use, the introduction of acidic groups is carried out by phosphorylation with phosphoric acid.