Method of producing 2,2-bis-(carboxy)-1,3-propanedicarboxylic acid by oxidation of pentaerythritol

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing 2,2-bis-(carboxy)-1,3-propanedicarboxylic acid (methane-tetracarboxylic acid, MTCA). The method is realised by oxidising pentaerythritol with potassium permanganate solution, taken in molar ratio of potassium permanganate to pentaerythritol of (6.4-6.6):1, in a medium of potassium carbonate at temperature of 65-70°C for 4-5 hours and held at temperature of 20-25°C for 8-10 hours; excess oxidant is removed by adding oxalic acid. The obtained mixture is filtered to separate the residue; the filtrate is evaporated; the evaporated solution is neutralised with hydrochloric acid to obtain carboxylic acid. The end product is separated by crystallisation and filtration at temperature of 0°C.

EFFECT: high output of the end product.

1 tbl, 1 ex

 

The invention relates to the field of production of polybasic carboxylic acids, namely 2,2-bis-(carboxy)-1,3-proponderance acid (metacercaria acid, Shuttle), which can be used as a raw material component for obtaining polyesters, including alkyd resins, curing agents for synthetic resins, in the manufacture of stabilizers and antioxidants, polymers, surfactants, plasticizers for polyvinyl chloride, synthetic lubricating oils, polyurethane paints. Methanetricarboxylate acid can also be used in the pulp and paper, petroleum refining, paint and varnish industry, in the processing of plastics, rubber and other industries.

A known method of obtaining a carboxylic acid using the reaction of alcohols with carbon monoxide. Carboxylic acid is obtained by translation of the primary alcohol in the alcoholate of an alkali metal, the interaction of the alcoholate of an alkali metal with carbon monoxide at 120-130°C and a pressure of 0.6-0.8 MPa with the formation of salts of carboxylic acids, from which the hydrolysis in the acidic environment get carboxylic acid [Uschakov. Organic chemistry. The 4th edition. "Chemistry", M., 2002, s].

The disadvantage of this method is the complexity of the technological process, and in this way the floor is arranged polybasic carboxylic acid, as metacercaria acid.

A method of obtaining carboxylic acids, comprising the oxidation of a primary alcohol with oxygen in the presence of copper and other catalysts at 300-500°C [Per, Juvelen, Astrodisco. Organic chemistry. "High school", M., 1973. p.124].

The disadvantage of this method is the impossibility of obtaining polybasic carboxylic acids at high temperatures decompose to carbon dioxide.

A method of obtaining carboxylic acids by oxidation by the interaction of isoamyl alcohol with an oxidizing agent in an aqueous-alkaline medium, and as an oxidizer used oxygen-containing gas and the process is carried out at 50-130°C and a pressure of 0-10 MPa at the stationary layer of the catalyst is palladium on charcoal [RF patent №2024487, CL SS 53/126, SS 51/235, publ. 15.12.1994].

The disadvantage of this method is the impossibility of obtaining a polybasic carboxylic acids, in particular Shuttle.

A method of obtaining [A.S. USSR №1790157, CL SS 51/16, SS 59/84, publ. 10.08.2000] benzoylamino acid oxidation of acetophenone potassium permanganate at a temperature of 35-45°C in an alkaline environment, and use acetophenone faction - waste production of phenol and acetone, as the alkaline environment of the use of an aqueous solution of potassium carbonate, and the process is conducted at a pH of 8,.

The disadvantage of this method is the low yield of the target product.

A method of obtaining salts methanetricarboxylate acid [patent JP 52128317, CL SW 61/00, SS 51/00, SS 55/24, publ. 27.10.1977], including the oxidation of pentaerythritol oxygen-containing gas in the presence of a palladium catalyst, neutralizing the acid with alkali.

The disadvantage of this method is the complexity of the technological process, not a high yield of product.

Closest to the proposed to the technical essence and the achieved result is known a method of obtaining a carboxylic acid, comprising the oxidation of a primary alcohol in an alkaline medium with potassium permanganate solution, filtering the reaction mixture, separating the precipitate of manganese dioxide, evaporation of the filtrate, the neutralization of a solution of mineral acids, alkalis and salts of carboxylic acid to slightly acid reaction medium to obtain carboxylic acid, the separation of carboxylic acid and drying, at the same time as the primary take alcohol isobutyl alcohol, oxidation carried out in the cold when the temperature of the reaction mass not higher than 5°C, potassium permanganate taken in excess, then the reaction mixture was incubated for 12 hours, spend filtration, evaporation of the filtrate to neutralize used as mineral acid 10%solution of sulfuric key is lots the allocation received somaclonal acid is carried out by extraction with diethyl ether. To create an alkaline environment using sodium carbonate or potassium [Nderrisiken. Workshop on organic chemistry. The 4th edition. State scientific and technical publishing house. M., 1956, pp.96-97].

The disadvantage of this method is the relatively low yield of carboxylic acid.

The purpose of the invention: improved output methanetricarboxylate acid.

This goal is achieved in the proposed method obtain 2,2-bis-(carboxy)-1,3-proponderance acid, comprising the oxidation of a primary alcohol in an alkaline medium with potassium permanganate solution, filtering the reaction mixture, separating the precipitate of manganese dioxide, evaporation of the filtrate, the neutralization of a solution of mineral acids, alkalis and salts of carboxylic acid to slightly acid reaction medium with obtaining carboxylic acids, separation of carboxylic acid and drying, characterized in that as the primary alcohol take pentaerythritol in aqueous solution with addition of potassium carbonate, the resulting solution was injected into a solution of potassium permanganate, taken in a molar ratio of the potassium permanganate: the pentaerythritol is (6,4-6,6):1. Oxidation of pentaerythritol carried out at a temperature of 65-70°C for 4-5 hours and then the reaction mixture was kept at a temperature of 2025°C for 8-10 hours, the excess oxidant is removed by addition of oxalic acid. The selection of the target product is carried out by crystallization and filtration at a temperature of 0°C and the drying is carried out at room temperature.

The chemistry of the process is described by the following equations:

Carrying out the oxidation in the proposed conditions at specified intervals indicators process provides a high yield of the target product. Carrying out the oxidation at a ratio of potassium permanganate: pentaerythritol is (6,4-6,5):1 at a temperature of 65-70°C for 4-5 hours and it continued at 20-25°C for 8-10 hours provides an effective course of oxidation of pentaerythritol with the formation of the Shuttle. The flow rate of the oxidant is less than the molar ratio of the potassium permanganate: pentaerythritol than 6,4:1, is not sufficient for complete oxidation of the alcohol with the formation of the Shuttle. The flow of oxidant higher molar ratio of the potassium permanganate:pentaerythritol than the 6.6:1, does not increase the yield of the product and therefore not feasible due to cost overruns of this reagent and oxalic acid. Lowering the temperature of the reaction mixture below 65°C, and process duration less than 4 hours, then the temperature exposure of the reaction mixture below 20°C, prolonged the ti shutter speed less than 8 hours leads to a decrease of the yield of the target product from incomplete oxidation of pentaerythritol. The increase in the temperature of the reaction mixture above 70°C also results in lower yield of the desired product due to the occurrence of adverse reactions. The increase in the duration of the oxidation process more than 5 hours, extracts more than 10 hours leads to lower productivity and waste of energy. Remove excess oxidant by adding oxalic acid leads to improving the quality of the target product, provides the powdery white product. The selection of the target product by crystallization and filtration at a temperature of 0°C provides high output, minimum loss of the target product from the mother liquor.

The appropriateness of the limits of process indicators shown in the example in table 1.

Example 1. Pre-prepare a solution of pentaerythritol by dissolving 10.2 g of pentaerythritol (0,075 mol) and 15 g of potassium carbonate in 500 ml of water. Also prepare a solution of the oxidizing agent by dissolving 77 g of potassium permanganate (0,49 mole) in 1000 ml of water. In a flask equipped with stirrer, reflux condenser and addition funnel, was placed a solution of potassium permanganate. While stirring the flask gradually introduce a solution of pentaerythritol. The molar ratio of the potassium permanganate: pentaerythritol is equal to 6.5:1. The oxidation reaction of pentaerythritol is accompanied by heat. When widening solution eritria the temperature of the reaction mixture support equal to 68°C. The duration of dosing of a solution of alcohol 5 hours. After introduction of the solution of pentaerythritol, the temperature of the reaction is reduced, then the reaction mixture was stirred at 23°C for 10 hours. The reaction mixture is a suspension of pink colour in the sediment falls manganese dioxide formed in the oxidation reaction of the alcohol. The excess oxidant is potassium permanganate is removed by adding to the reaction mixture of oxalic acid, taken in the form of a 20%aqueous solution. Oxalic acid is added until disappearance of the pink color of the reaction mixture. Next, the reaction mixture is filtered, thus separating the precipitate of manganese dioxide. The filtrate is evaporated under stirring up to a volume of 100 ml. Received one stripped off the solution is cooled and carry out the neutralization of the alkali and potassium salts of carboxylic acid, a mineral acid to slightly acid reaction medium (pH=6,0-6,5). As the mineral acid used 20%solution of hydrochloric acid. By neutralizing potassium salt is formed methanetricarboxylate acid. The resulting solution Shuttle is placed in an ice bath, and the crystallization at a temperature of 0°C emit tetrahydrate crystals methanetricarboxylate acid. Crystals Shuttle is separated on a filter, washed with ice water and dried at room temperature. Get 11,0 g of Tetra is igrata 2,2-bis-(carboxy)-1,3-proponderance acid. The product yield is of 55.5%, calculated on the anhydrous acid.

The way to obtain 2,2-bis-(carboxy)-1,3-proponderance acid, comprising the oxidation of a primary alcohol in an alkaline medium with potassium permanganate solution, filtering the reaction mixture, separating the precipitate of manganese dioxide, evaporation of the filtrate, neutralizing alkalis and salts of carboxylic acid a solution of mineral acid to slightly acid reaction medium with obtaining carboxylic acids, separation of carboxylic acid and drying, characterized in that as the primary alcohol take pentaerythritol in aqueous solution with addition of potassium carbonate, the resulting solution was injected into a solution of potassium permanganate, taken in a molar ratio of the potassium permanganate: pentaerythritol is (6,4-6,6):1, the oxidation is carried out at a temperature of 65-70°C for 4-5 h and incubated at 20-25°C for 8-10 h, the excess oxidant is removed by addition of oxalic acid, separation of the target product is carried out by crystallization and filtration at a temperature of 0°C and dried at room temperature.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing 2,2-bis-(carboxy)-1,3-propanedicarboxylic acid (methane-tetracarboxylic acid, MTCA). The method is realised by oxidising pentaerythritol with potassium permanganate solution, taken in molar ratio of potassium permanganate to pentaerythritol of (6.4-6.6):1, in a medium of potassium carbonate at temperature of 65-70°C for 4-5 hours and held at temperature of 20-25°C for 8-10 hours; excess oxidant is removed by adding oxalic acid. The obtained mixture is filtered to separate the residue; the filtrate is evaporated; the evaporated solution is neutralised with hydrochloric acid to obtain carboxylic acid. The end product is separated by crystallisation and filtration at temperature of 0°C.

EFFECT: high output of the end product.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing 2,2-bis-(carboxy)-1,3-propanedicarboxylic acid (methane-tetracarboxylic acid, MTCA). The method is realised by oxidising pentaerythritol with potassium permanganate solution, taken in molar ratio of potassium permanganate to pentaerythritol of (6.4-6.6):1, in a medium of potassium carbonate at temperature of 65-70°C for 4-5 hours and held at temperature of 20-25°C for 8-10 hours; excess oxidant is removed by adding oxalic acid. The obtained mixture is filtered to separate the residue; the filtrate is evaporated; the evaporated solution is neutralised with hydrochloric acid to obtain carboxylic acid. The end product is separated by crystallisation and filtration at temperature of 0°C.

EFFECT: high output of the end product.

1 tbl, 1 ex

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