SU471718A3 - The method of producing glycidol - Google Patents

Description

(54) METHOD FOR OBTAINING GLYCIDOL

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corresponds to 1: 1 (molar). It is desirable that one of the reagents is present in the bulk, as this increases the reaction rate. Usually, allyl alcohol is used as a reagent used in excess, since the process of isolating it is much simpler than peracetic acid.

The recommended molar ratio of 1 {yl of allyl alcohol and padacetic acid is 1.3-3: 1.

The rate of epoxidation and allyl alcohol increases with increasing temperatures.

It is recommended to carry out the process at 25-100 ° C, preferably at 40-65 ° C, ml at a lower temperature, for example room temperature. However, it takes 40 hours to complete the reaction at Komiat the 1st temperature, and it takes about 2.5-4 hours to complete the reaction in a batch process at 60 ° C. The reaction rate decreases dramatically when the conversion rate of the reagent present in the minute amount increases to 75%, especially to more than 85%.

In this regard, it is recommended to carry out epoxidation before transformation of the acetic acid into the target product by 70-90% and then conduct epoxidation in the second stage. Before the second stage of epoxy-dichloride, part of the solvent and part of acetic acid should be removed, as well as part of the glycidol present in the reaction product mixture. Preferably, these compounds are removed continuously during the second epoxidation stage.

Unreacted papus acetic acid and altslovy alcohol interact in a distillation column, which allows to combine this operation with the removal of rastup and acetic acid, as well as with the purification of glycidol. Further, solvent is preferably stripped with 10-14 DEG of 100-400 mm Hg. at the same time, the residue contains unreacted allcellular alcohol, p-acetic acid, acetic acid, dissolved in the initial solution of peracetic acid and formed with time of the epoxidation reaction, the target glycidol high-level impurities formed during the reaction. Glycidol is recovered from this mixture by continuous distillation in a column with an equivalent number of theoretical plates, each at a pressure of 1-50 mm Hg. Art., preferably at 10-30 mm, Hg. Art.

To distill the mixture in order to obtain the target glycidol with a purity level of 95%, preferably over 98%, a column with an equivalent number of theoretical plates of 8 is used. The column also operates under conditions leading to a relatively contaminated glycidol product, for example 80-95% of the whole. Crude glycidol is subjected to DISTRILLATION in a second low pressure column to obtain pure glycidol.

In the first stage of epoxy dichloride, a series of byproducts is formed, such as high boiling acetyons, glycidyl ethers and others, which have a long chain of glycidol polycondensates, especially in the absence of solvents. To reduce the amount of by-products, the residence time of the epoxidation reaction mixture in the column after stripping should be short and be less than 2-5 minutes.

In the upper part of the rectification K9lona, from which acetic acid is taken and which can also be used as a reactor for the second epoxidation stage, the temperature is maintained at 25-30 ° C. The column is equipped with a reboiler at the bottom. High-binding materials are taken from the reboiler at 140-160 ° C.

Glycidol is taken from the corresponding plate above the reboiler at 75-85 ° C.

When the distillation process is carried out in two columns, the reboiler of the first column can be operated at a minimum temperature of, for example, 80 ° C and 100 ° C, glycidol is taken from the reboiler. This produces 80-95% glycidol, which is purified in a second distillation column at 65-90 ° C or used without purification.

It is desirable to use the distillation column shown in the drawing to isolate glycidol.

The feedstock, which is a mixture of glycic valley, nadic acid, acetic acid, and allylose sp1; mouth, is introduced through a pipeline / into a column divided into three UN sections 2, 3, and 4.

Section 2 is an assembly section and serves to fractionate peracetic acid, acetic acid, and allyl alcohol from glycidol. This section is also used as a second stage reactor, in which the interaction of unreacted peracetic acid and allyl alcohol occurs at 25–30 ° C. The vapors take away) 13 top1 {part of the constriction of it and take them through pipeline 5 to the refrigerator 6.

Section 3 also has a packing and, as a stripping section, providing for the separation of acetic acid from glycidol, whereby glycidol moving in the Bnez column contains in the lower section of section 3 less than 1% acetic acid. The residence time in this section should be min., And the temperature should be adjusted so as to form a minimum amount of by-products. The temperature in the upper part of the section is maintained at 40-50 ° C, and in the lower part of it 60-65 ° C.

Section 4, also provided with a packing, serves to separate glycidol from acetins, which are formed in the process. The temperature in the upper part of this section should be kept sufficiently high to separate the glycindol in vapor form, but such that the condensation of glycidol leading to

To ozazozaniya resinous substances, oyl minimized.

The reboiler 7 operates at 140-160 ° C. The lower part of section 4 has a temperature approaching the temperature of the reboiler.

The described distillation column is the co: 1 combination of separation column and reactor. Pressure in the colon; e should be 20-30 mm Hg. Art. However, it is necessary that the residence time in it is minimal, for example 2-5 minutes.

In this column, the height of the packing layer should create the possibility of obtaining the maximum number of theoretical plates per unit length of installation. It is recommended that section 2 be equivalent to 2-3 theoretical plates, section 3 8-9 theoretical plates, and section 4 1-2 theoretical plates.

Example A 12-liter flask having a 7-necked head, equipped with an aluminum cooling coil, a refrigerator, a mechanical mixer, a thermometer, two funnels for the supply of reagents, an inlet and an outlet for cooling the coil, was loaded with 12 mol of peracetic acid in the form of 15-30% -; south solution in acetone containing 6-8% acetic acid and allyl alcohol.

The feedstock is injected with one repeat for 39 minutes. The table shows the ratios between the reagents:, the temperature, the reaction duration, the degree of conversion of allyl alcohol and the yield of glycidol (based on allylose G: alcohol), all parts and percentages by weight.

364 .... served at a rate of 3.5 ml / min to the midpoint of a distillation column operating under a pressure of 100 mm. Hg Art. Acetone is taken as the head fraction and it contains less than 1% acetic acid. Crude glycidol with the content of the main substance of 98% is taken from the lower part of the column and sent to the next column, operating under a pressure of 29 mph. Art. Acetic acid 2 is discharged as a head fraction along with an allyl sp: mouth that has not undergone transformation. The high-boiling components are taken from the bottom of the column, and at the level of the first plate above the reboiler section, the vaporized hl: cidol containing 1% acetic acid is withdrawn, which ultimately corresponds to 98.5% glycidol based on the feedstock.

Similar results are obtained when using the same method, but replacing acetone with ethyl acetate, methylal, benzene, and chloroform.

Subject and reference

Claims (3)

1. A method of producing glycidol by treating allyl alcohol tsaduksus 1ry acid; Cutting followed by excreting the desired product 1: Pesticides, characterized in that. For the purpose of the PRODUCTION of the yield and quality of the target product, allyl alcohol and peracetic acid are used. acid in a molar ratio of 1.3-3: 1 and the process is carried out in an anhydrous organic solvent to convert peracetic acid into the target product ia 70- 90%, from the reaction mixture. otgoi; from part the solvent and the resulting vinegar: the first acid remaining after this mixture is subjected to rectification iodine pressure of 20-30 mm RT. Art. when the residence time of the reactants in the zone of the perstones ::: iieHce is 5 min with continuous selection of reaction products from the bottom of the column, pr :: 140-160 ° C and unreacted allyl sp:; mouth and byproduct: 30 ° C with recycled allylose alcohol. 2. The method according to p. 1, except for the fact that the solvent is used with an inert solvent as the inert solvent. 30-80 ° C. 3. The method according to paragraphs. I and 2, characterized in that the solvent used is ethers and esters, low molecular weight alcohols, ketones, chloroform | 0pm, Carbon tetrachloride. ,; LC