PL330556A1 - Method of obtaining 2,2,4-trimethylpentadiole-1,3 monoisobutyrate - Google Patents

Description

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Process for the preparation of 2,2,4 * trimethylpentanediol -1,3 monoisobutyrate.

The present invention relates to a process for the preparation of 2.2.4-trimethiopentanediol-1 3 monoisobutyrate from isobutyraldehyde. The product is used as an additive to paints and varnishes, pest control agents, glue masses, and as a plasticizer and plasticiser. According to known methods, the trisubstituted glycol derivatives are obtained by aldol condensation of aldehydes having 2-10 carbon atoms and having one hydrogen atom on the carbon in the α-position to the aldehyde group. In the presence of strongly basic catalysts, the condensation product of two molecules of issmastaldehyde undergoes a subsequent reaction of Canizarro and Tishchenkl with another molecule of isobutyraldehyde, and so from isobutyraldehyde according to the scheme:

GH, S4H3 / CH3NCH-[alpha ]H-[alpha] -CH2-O-C-CHx CH, OH CH8 GHi gives 2.2.4-trimethylpano-ST-ethanediol-1.3 monoisobutyrate.

The reaction takes place in the presence of basic catalysts such as alkali metal or alkaline earth metal hydroxides, alkali metal oxides and alkali metal alkoxides, alkali metal salts such as sodium isobutyrate, as well as compounds facilitating the homogenization of the reaction mixture, such as IV - tier ammonium compounds, phosphorus compounds, ftp, with glycols polyalkite. i! V · · 1! * ’1 " '' * “* £ w -ίΤ ·· ίΓίΓίΚ ^^ ΐ; ^; α'.Λ? Ώ iii ii ··· " '·' ii mmi-tm

According to DE 3833 033, the monoisomailane 2.2.4-trimethyl-pentanedio-t. 3 is obtained in a continuous process from isobutyraldehyde {L K max. 2) against 5 - 20% aqueous sodium hydroxide solution. This process is characterized by a low degree of conversion of isobutyraldehyde to the desired product. In EP 0317 977, the authors presented a method for the production of 2,2.4-triethylpentanediol-1,3 monoisobutyrate from isobutyraldehyde in the presence of an aqueous solution of sodium hydroxide as a catalyst. The process is carried out in a reactor in the form of a node at a temperature of 90 - 11 (fC). In order to limit the evaporation of isobutyraldehyde, it is necessary to use a pressure of about 10 atm. The product from the reactor is led to a distillation boiler, where at 180 - 190 ° C no more than reacted isomast aldehyde.

The methods for the preparation of monoisomtlane 2.2.4-thimethylpentane-diol-1.3 described in the literature require, in order to ensure a patched degree of isomer aldehyde conversion, the use of long reaction times, high temperatures, or the use of pressures. Under these conditions, high amounts of more highly condensed products are formed (e.g. dilsobutyrate 2 2.4-trimethylpentanediol-1.3), which will lower the selectivity of the process, and it is not always possible to obtain high product yields.

The object of the invention is to provide a process for the preparation of 2.2-4-trimethylpentanediol-1.3 monoisobutyrate which achieves a high degree of isobutyraldehyde conversion to product and low amounts of by-products.

The essence of the invention is so powerful that the process of producing monoisobutyrate 2.2 4-trimethylpentanediol-1,3 is carried out in a two-stage manner, in which in the first stage a mixed solution of isobutyraldehyde with a catalyst, which is an aqueous solution of sort hydroxide with a concentration of 30, is introduced into the tubular reactor. - 60%, most preferably 35-45%, and the molar ratio of isobutyraldehyde to NaOH is 0.02-0.06, most preferably 0.035-0.05, the process is carried out at a temperature of 50-80 ° C, most preferably 60-70 ° C, for a period of 30 to 240 s, most preferably 60-120 s, the mixture thus produced is introduced into a tank reactor equipped with a distillation column * 2/3 of its height, the reaction of raw materials is carried out at a temperature of 60-100 ° C, most preferably 70-90 ° C. temperature on " ii-ι S.0p :: ;; J,:,: '' * V i > and ": .ίίΰ {.: the jacket of the distillation column is 64-8G ° C, most preferably 70-75 ° C, the residence time of the reactants in the reactor is 30-300 sec, most preferably 60-120 sec.

Initial conversion of isobutyraldehyde to 2.2.4-trimethypentanediol monoisobutyrate takes place in a tubular reactor, from which the reaction mixture is directed to a tank reactor equipped with a distillation column in which further isobutyraldehyde is converted to the product, and not converted isobutyraldehyde the top of the column is condensed and recycled to the tank reactor. The crude product is washed with water and the organic layer is separated from the water layer, in which sodium isoma and sodium hydroxide are dissolved. The isobutyraldehyde is distilled from the organic layer and returned to the tubular reactor. In Unexpectedly, it turned out that it is possible to obtain a high degree of conversion of isobutyraldehyde to monoisobutyrate 2 2.4-tn-methylpentane-dtolu-1.3 and at the same time to reduce the formation of by-products in the case of the isobutyraldehyde condensation process in a two-stage process, in which the first stage of the reaction is carried out in the reactor in short periods of residence of the reactants and at a temperature of 60-70C, and the pre-reacted mixture is directed to a tank reactor, where the further reaction of raw materials takes place at the temperature of 80 * 95 ° C for 60-120 s, and the isobutyraldehyde distilled from the second of the reaction stage, withdrawn from the top of the distillation column is condensed and returned to the tank reactor.

The method of the invention produces 2,2.4-trimethylpentanediol monoisobutyrate in an amount of about 75% to the isobutyraldehyde used in the synthesis, and the selectivity is calculated by the ratio of the amount of isobutyraldehyde reacted to 2.2.4-trimethylpentanedioate monoisobutyrate to the total amount of 1.3 reacted. Isobutyraldehyde (2.2.4-trimethylpentane di-diol-1.3, 2.2.44-trimethylpentane-diot-1 3 monoisobutyrate, 2.2.4-trimethylpentane-1.3-diisobutyrate, isobutanol and others) is greater than 98%.

The 22.4-trimethylpentane-diol-1.3 monoisobutyrate obtained by the process according to the invention is stable and contains a small amount of organic impurities

Examples.

Isemasium aldehyde and 40% aqueous sodium hydroxide solution were introduced into a tubular reactor (glass coil with a diameter of 5 mm and a volume of 20 or 40 cm3}, thermostated with a water jacket, the molar ratio of isobutyraldehyde to sodium hydroxide was 0.04. The reaction products were fed to the column 2 cm diameter and 30 cm long, at 2/3 of its height, and into a 250 or 500 cm3 glass jug heated with an electric mantle. Isobutyraldehyde distilling from the top of the column was dropped and introduced into the jug. The crude product was removed from the glass jug by a pump and its composition was determined by gas chromatography.

The test conditions and the test results obtained are presented in the table.

Response time [s | * tubular reactor * tank reactor 60 60 60 120 120 60 60 60 Temperature fCj .. * tubular reactor 60 60 60 60 • tank reactor 90 90 90 90 • column top 70 70 70 65 Process results. * amount of product 0 |% J 73.60 74.70 68.10 69.53 • selectivity α {%] 98.34 98.39 98.70 99.10 11 - the ratio of the amount of isobutyraldehyde, which has reacted to 2.2.4-trimethylpentanediol monoisobutyrate to the amount of aldehyde used in the synthesis, 12 - the ratio of the amount of isobutyraldehyde reacted to 2.2.4-trimethylpentanediol-13 monoisobutyrate to the total amount of isobutyraldehyde reacted.