SU707907A1 - Method of preparing glycolic acids - Google Patents

Description

one

The invention relates to the field of basic organic synthesis, specifically to a method for producing glycolic acids of the general formula:. HOOC- | C, H: 0-CH2 / c-COOH, where PI, 2ilm, which are widely used for the production of detergents, in the textile and leather industry, as coagulant for rubber and synthetic products, for the synthesis of esters , as an oil demulsifier, as well as in other areas of the national household,

Glycolic acids are produced industrially by the oxidation of polyethylene glycols with concentrated nitric acid. The closest in technical essence and achievable results is the method of producing glycolic acids, in particular diglycolic acid, by oxidizing diethylene glycol with 30-65% nitric acid with an acid: glycol ratio equal by weight at a temperature of 35-80 ° C in the presence of Ozi discoloration of the reaction mass, followed by distilling off unreacted nitric acid and water and isolating the target product by extraction with an organic solvent. The yield of the target product is 124 wt.% With the content of diglycolic acid .99,7% 1.

The disadvantage of this method is the low efficiency of the process of obtaining individual glycolic acids.

The purpose of the invention is to reduce the cost of the process. The goal is achieved by the described method of obtaining glycolic acids of the general formula: - -. NOB- | CH2-0-CH21 „-COOH„ GD P -1,2 or3,

the fact that the products

tar containing 10-15% of glycols, 10-45% of lycol esters, up to 40% of unidentified resinous compounds and up to 10% of mechanical impurities of inorganic nature

is subjected to oxidation with 50-70% nitric acid at a ratio of acid: pitch products of equal weight by weight, preferably at a temperature of 5075 ° С (usually 60-70С) in the presence of

catalyst - tin chloride, taken in the amount of 0 05--0, so. L for the products of tar, with ncc.; R; .iv-i is a common extract of unreacted acid and water and release of the target extraction product by means of oj-rsHi: CHSS1SIM solvent. The yield of the target product is 118-122 wt.% With a glycolic acid content of less than 99%. Distinctive features of the process is that the tar of polyglycols containing 10–15% glycols, 10–45% glycol esters,. up to 40% of unidentified resinous compounds and up to 10% of mechanical impurities of an inorganic nature are subjected to oxidation with 50–70 nitric acid at an acid ratio: resinous products of 34–7: 1 by weight, in the presence of tin chloride catalyst, taken in a quantity of 0.05– 0.1% by weight of the products of the tar which makes the process cheaper. The products of the resinification of polyglycols, in the form of bottoms, are formed; during the process of extraction of polyethylene glycols with aromatic hydrocarbons with subsequent vacuum distillation. The advantage of the proposed method is that it allows to obtain individual glycolic acids, which are valuable petrochemical and chemical products from bottoms, residues from the distillation of polyglycols, which have not previously been used and sent either to incineration or to dumps, which thus, it contributes to environmental protection. PRI m e r 1. 1390 g of a 60% HNO3 are placed in a 3 necked flask with an agitated and refluxed water condenser and heated to 55 gbO ° C. A mixture consisting of 128 g of resinous products in the form of the distillation residue of diethylene glycol (DEG) is then added under stirring for 1.5 hours, the content of DEG is 15% and 0.13 g of tin chloride, and the mass is mixed 20 min, with b54-70 s. The mixture is discolored, then distilled off under vacuum of unreacted -JINO, and the bottoms to remove traces of HNO are washed with water which is also distilled off under vacuum. This treatment yields 152 g of crystalline product, from which, after dissolving in methanol, 138 g of diglycolic acid is recovered (121% wt. Per organic part of the raw material) in the form of a white powder of the like substance, m.p. 142 ,, purity according to GLC 99.1%. Elemental analysis: Found, wt.%: C 35.98; H 4.59; About 59.43. SdH Og. Calculated, wt.%: C 35.80; H 4.4 O 59.72 ,. Acid number, mg KOH / g: calculated - 838.0; Nilo: 836.4, Example 2. A mixture containing 3 g of the product of the mixture as a residue from the distillation of DEG (the content of DEG is 10%) and 0.04 g of chlorine tin is introduced into 500 g of 50% HNO 55 ° C in for 1 h, as described in example 1. Next, the reaction mass is stirred for another 30 min at. the monster becomes colorless. After removal of HNOj and water, 84.8 g of a crystalline product are obtained, after which 76.8 g of diglycolic acid (118.3% by weight per organic part of the product) as a white powder with m.p. 142.4 ° C, pure according to GLC - 99.0%. Elemental analysis: Found, by weight,%: C 35.60; H 4.56; 59.84. . Calculated, wt.%: C 35.80; H 4.48; 59.72. Acid number, mg KOH / g: found: 840.0; calculated: 83.8,0. Example 3. A mixture containing 73 g of tar products in the form of a distillation residue from DEG distillation (DEG content - 12%) and 0.07 g of tin chloride, is oxidized to 6-50 g. 63% HNO3 at 50-55 ° С within 1.5 hours and at 65-75 ° C for 20 minutes, as described in Example 1. 85.8 g of product are obtained, from which 77.8 g of diglycolic acid (119.8% per organic part of the raw material) in the form of a white powdery substance with So pl. 142.7 ° С, purity according to GLC - 99.5% V Elemental analysis: Found, by weight,%: С 36.03; H 4.36; About 59.61. . . Calculated, wt.%: C 35.80; H 4.48; About 59.72. Acid number, mg KOH / g: found 839.5; calculated 838.0. Example 4. A mixture containing 80 g of resinous tar products from the distillation of triethylene glycol (TEGa) (TEG content 20%) and 0.04 g of tin chloride is oxidized to 720 g of 70% HNO for 1.5 hours at 55 -60 ° C and within 0.5 hours at 70-75 ° C, as described in Example 1, 95.8 g of product are obtained, from which 87.8 g of ethylene-glycolic acid is extracted with ethanol (122.0 wt.% on the organic part of the raw material) with So pl. B1,8 ° C, purity according to GLC - 99,0%. Elemental analysis: Found, wt.%: C - 41.03; H 5, .90; O - 53.07. S Oh. - 40.45; H Calculated, wt.%: C 5.63; About 53.92.

Acid number, mg KOH / g: found 629.2; calculated 630.5.

Example 5 A mixture containing 80 g of tar products in the form of a distillation residue from the distillation of a TEG (TEG content is 15%) and 0.08 g of chlorine. tin, acidified with 690 g of 65% HNOj at 55 ° C for 1.5 h and at 70 ° C for 25 min, as described in Example 1. Obtain 94.5 g of product, from which 86 are separated by acetone , 5 g of ethylene-bis-glycolic acid (120.2 wt.% On the organic part of the raw material) with So pl. 82, and purity according to GLC - 99.3%.

Found, wt.%: C - 40.96 H 5, 95 O - 53.69.

C H oObCalculated, wt.%: C - 40.45;

H - 5.63; O - 53.92.

Acid number, mg con / g: found 629.0 g calculated 630.5.

Example 6. A mixture containing 90 g of the tar products in the form of the cubic residue from the distillation of tetraethylene glycol (TetraEg) (the content of TetraEG is 15%) and 0.09 g of chlorisg

addition of tin, oxidized 623 g of 70% HNO at 50-60 ° C for 1.5 h and at 70-75 s for 0.5 h, as described in Example 1. 104.4 g of product are obtained from which methyl ethyl ketone 94.4 g of tetraethylene glycol acid (118.1% by weight on the organic part of the raw material) with m.p. 55.4 ° C and purity according to GLC 99, 1%.

Found, wt.%: C - 42.70 H 0 5.93; O - 51.37.

.

Calculated, wt.%: C - 43.05 H - 6.20; O - 50.75.

Acid number, mg KOH / g: find5 but 503.9; calculated 505.2,

The advantage of the proposed method is that it makes it possible to use polyglycol production wastes to obtain

0 valuable glycolic acid. In addition, the processing of these wastes, which have not previously been used and were sent for incineration, or were discharged, contributes to the reduction of environmental pollution.

Claims (2)

1. A method of producing glycolic acids of the general formula :, coos (CH2-o-cH, coqH, where U1-1.2mlyZ c: using an oxidation reaction with nitric acid, with heating, followed by distilling off unreacted nitric acid and water and isolating the target product by extraction with an organic solvent, characterized in that, in order to reduce the process, the tarring products of polyglycols containing 10-15% of esters of glycols, up to 40% of unidentified resinous compounds and up to 10% of mechanical impurities of non-narcotic nature / oxidize 50-70 a :. acid at a ratio of KHCJIOT and: other 7079078 Dull tar 3-7: 1 by weight at pr-3. Way pop 1, the presence of a catalyst is different from that of chloride and that the oxidation of the pro-tin is taken in an amount of 0.05-d at 60-70 ° C. 0.1 wt.% On the products of tar. Sources of information, 2. The method according to, I differ-5 1. Laid out for the Federal Republic of Germany u and with the fact that the oxidation of provo-№ 2244243, cl. 12c 11 publ. 1974 d t 60-65% nitric acid. (prototype). taken into account in the examination