SU729174A1 - Method of preparing 4,5-dihydrosylvan - Google Patents

Description

Union of Soviet

Socialist

Republics

0.729174

O and E

Inventions

TO THE AUTHOR'S CERTIFICATE for inventions and discoveries (61) Additional to author. certificate-wu _ (22) 3Approved 06.09.7 6 (21) 2398170/2 3-04 with the addition of application No. - (23) Priority _

Published on April 25, 80. Bulletin No. 15

Date of publication of the description 28.04.80 (51) M. Cl ² 'C 07 D 307/28 (53) UDC 547.7 22.

.3.07 (088.8) (72) The inventors

V. S. Markevich, G. A. Stepanova, L. V. Shumakova,

V.E. Nevaeva, T.A. Puchkina, G. f. Stychinsky and V.I. Garanin (71) Applicant (54) METHOD FOR PRODUCING 4,5-DIPSCHROSILVAN

An improved method for producing 4,5-dihydrosilvane (DHA), which is used in the production of vitamin B {.

A known method for producing 4,5-dihydrosilvane by dehydration of jf-apetopropyl ⁵ alcohol at 160-240 ° C in the presence of mineral acid, followed by separation of 4,5-dihydrosilvanum and water vapors by distillation, cooling and isolation of the desired product from the azeotrope [1] .

The disadvantage of this method is the use of acid, which leads to the formation of tarry products, the amount of which reaches 30%.

In addition, the use of mineral acid leads to corrosion of the equipment and requires the neutralization of wastewater. _m

The aim of the invention is to simplify the process,

This goal is achieved by the fact that J - aketopropyl alcohol (APS) is subjected to heating at 190-203¾ in an inert gas stream, the speed of which is 1-5 volumes per minute per 1 volume / j - of acetopropyl alcohol, with a vapor contact duration of 4,5 dihydrosilvane and water 10-30 s,

The difference of the proposed method from the known one is that the process is carried out in a stream of inert gas, the speed of which is 1-5 volumes per minute per 1 volume of 2G-acetopropylic alcohol with a contact duration of 4,5-dihydrosilvane vapor and water of 10-30 s,

To reduce the duration of contact of the DHA vapor with the surface of the apparatus, it is given from the heating zone using an inert gas current, such as nitrogen. Thus, for the implementation of a non-catalytic reaction, the principle of the minimum residence time of DHA vapor in the reflux zone must be observed, for which it is necessary to use equipment with a minimal reflux surface. Otherwise vozdeyst723174 viem under elevated temperature in the reflux zone of the DHS can react with water formed by dehydration of APS and turn into AG1S., The system will work as ob- ₅ inverse refrigerator and much of DHS (due to the reverse reaction water) will return to the cube in the form of APS, and the distilled part of the DHA will contain significant impurities of the APS. The minimum 10 residence time of DHA vapor and water in the heating zone is ensured by the use of conventional distillation equipment, in which the vapor separation efficiency is minimized, i.e. AP-15 is applied; single evaporation parat. The resulting DHA is easily removed from the reaction zone due to the large difference in the boiling points of APS and DHA. The optimal separation rate and yield of distillate 20 _; (about .90%) Achieved when the ratio of the surface of reflux and the evaporation screen is not more than 2: 1, respectively. An increase in the reflux zone and, consequently, an increase in the duration of the ²⁵ contact of the DHA vapor and water lead to their interaction with the formation of APS and the cessation of distillate evolution. Thus, an increase in the ratio of the surface of reflux to the surface of evaporation to ³⁰

5: 1, while maintaining all other synthesis conditions, leads to a decrease in the rate of DHA release by 2 times (from 14.9 g / h to

7.4 g / h).

Azeotrope DHS - water boils at 72 ° C, ³⁵

APS is loaded into the distillation cube (not less than 1/2 volume) and then, as distillate is distilled off, APS is added so that a constant liquid level in the cube is maintained. The rate of nitrogen ⁴⁰ supported 2-4 alive gas volume per unit volume of the bottom liquid per minute. Distillation DHA together with water is collected in a cooled collection. After separating the aqueous layer, the organic ⁴⁵ layer is further subjected to azeotropic distillation to dry and isolate pure dry DHA.

Example 1. In a glass 4-necked cube for distillation under atmospheric pressure with a capacity of 90 ml, equipped with a thermometer, a capillary for nitrogen supply, a dropping funnel and a glass reflux condenser with a working zone volume of 11 cm ³ , 48 g of APS containing 96 , 9% of the main Substance and 3.0% of water. 'The ratio of the reflux surface to the evaporation surface is 1.7: 1. When the temperature in the cube is brought up to 190 ° C and nitrogen is supplied at a rate of 195. ml / min, the dihydrosilvap heteroazeotrope is distilled off - water with a speed of 15 ml / h at a temperature in pairs of 68-74 ° C. At the same time, the reaction mixture is replenished with fresh APS at a rate equal to the rate of heteroaseotrope extraction. The duration of the experiment is 4 hours. The contact time of dihydrosilvane and water in the vapor phase is 18 seconds. The result is 59.5 g of heteroazetrop composition: DHA 75.6 wt.% Water 24.4 wt.%. The output of dihydrosilvan, counting on the reacted APS, 93.5 wt.%. The composition of the bottom residue (47.5 g): APS 96.5 wt.%, Resin 2.7 wt.%, Water 0.8 wt.%. The degree of resinification, considering the loaded APS 1.2%. Losses are 1%. The aqueous layer is separated from azeotope dihydrosilvan — water, and the organic layer is dried and subsequently fractionated. The highlighted 4,5-dihydrosilvan has: the following indicators: so Kip, 79.3-80 ° C / / 746 mm Hg cZ 0.9018;

1.4351.

PRI me R 2. The experiment is carried out in a flow system on the device described in example 1. The reaction mass is taken from the bottom of the cube, cooled in the refrigerator (refrigerant - water) and collected in the receiver. The feed rate equals the sum of the sampling rates of the heteroazeotrope and the bottoms product. The output of the system to stationary mode is carried out within 3-3.5 hours

89 g of technical APS containing 65.9 g (74.1%) of the basic substance, 1.8 g (2 0 0%) of water and

21.3 g (23.9%) of resinous impurities. The feed is fed evenly at a rate of 5 mol / h. The duration of contact between the vapor of TPA and water 12 with the ratio of the surface of reflux and the evaporation surface of 1.57. The duration of the experiment is 15 hours. At a cube temperature of 19 5 ° C and a vapor temperature of 7 5 ° C, nitrogen speed / 30 ml / min, a DHS-water azeotrope is taken in an amount of 7 0.6 g.

In addition, 29.2 cubic meters of product containing »14.3 g (49.3 wt.%) APS, 1.0 g (3.2 wt.%) Water and 13.9 g (47, 5 wt.%) Impurities, and in the cube remains 64.2 g of a product of the same composition (i.e. 31.7 g of APS,

30.5 g of resin and 2.0 g of water). If necessary, the bottoms product is used in recycling. After separation of the azeotrope, 53.6 g of DHA, I / ²⁰ , are isolated in drying

I, 4,350. The purity of the product is confirmed by IR spectra, 5

The yield of dihydrosilvan, counting on the converted APS, is 89.5%, the degree of resinification of raw materials 2.2%,

Example Z. The experiment is carried out on the device described in example 2 in continuous ¹⁰ mode.

g technical APS containing 13 g (24%) APS, 34.2 g (63.2%)

-butyrolactone, 2.0 g (3.8%) of acetoproyl acetate, 0.3 g (0.6%) of water, and 4.5 ¹⁵ (8.4%) of the resin are loaded into a cube.

Feed with raw materials of the same composition is carried out uniformly at a rate of 10.8 ml / h. Duration, experience

II, 5 hours. The feed rate of nitrogen is 155 ml / h, ^{20 the} volume of the reflux zone is 24.5 cm ⁵ , the temperature of the cube is 190 ° C, the temperature in pairs is 7 O'C. The contact duration of DHA vapor and water is 18 s, the ratio of reflux and evaporation surfaces is 2: 1. ²⁵

During the experiment, 36 g of a heteroazeotropic, 142 g of a cubic product (including a residue of 53 g in a cube) of the composition are collected: APS 3.8 wt.%, Butyrolactone and acetopropyl acetate 8 3.2 wt.%, Water ³⁰

1.7 wt.% And resin. Resinification of raw materials is 2.6%.

After treatment of the heteroazeotrope, 1 27.2 g of 4,5-dihydrosilvanum and a _{part of} 0.9023 are obtained; n4 ° 1.4352. Purity produh- ³⁵ confirmed that the IR spectra.

The output of DHA, counting on the reacted DHA, is 86.5%. ₄₀

The technology of the proposed method is much simpler than the known technology. way. DGS are produced in one device both in a periodic and in a continuous manner, the bottom residue can be used for reloading (i.e., recycling) in order to extract dihydrosilvane to the fullest extent possible without any additional processing. Operations to neutralize acidic impurities, in contrast to the known method, are absent, which eliminates the corrosion of technological equipment and the neutralization of production waste. The proposed method makes it possible to reduce the number of process steps, reduce equipment costs.

Claims (1)

An improved method for the preparation of 4,5-dihydrosilbana (DHS), which is used in the production of vitamin Bj, is proposed. A known method for producing 4,5-dihydrosylvana by dehydrating -f-acetopropyl alcohol at 16O-24OC in the presence of a mineral acid, followed by separating 4,5-dihydroscopane vapor and water, cooling and separating the target product from averoprop I. The disadvantage of this method is the use of acid, which leads to the formation of resinous products, the number of which reaches 30%. In addition, the use of mineral acid leads to corrosion of the apparatus and requires the neutralization of wastewater. The aim of the invention is to simplify the process. This goal is achieved by subjecting f "ethopropyl alcohol (AG1C) to heating at 190--203 ° C in a stream of inert gas, the rate of which is 1-5 volumes per minute per volume - acetopropyl alcohol , at continuation of the contact of the vapor of 4,5-dihydrosylvana and 1O-ZO water. The difference from the known method from the known method is that the process is conducted in a stream of inert gas, the rate of which is 1-5 volumes per minute per volume Jf® topill sprint when the duration of contacts PA s 4,5-digidrosilvana water and 1O-30c To mind | n Sheni GVD vapor contact time with the surface of the apparatus l ate removed from its pomszschyu heating with an inert gas current such as nitrogen. Thus, in order to carry out a non-catalytic reaction, the principle of minimum dwell time of TDSs of DGS in the reflux zone must be observed, for which it is necessary to use equipment with a minimum surface of the reflux area. Otherwise, under the B03 / iertcivia, the elevated temperature in the reflux distillation of the DHS can react with water formed as a result of the dehydration of the APS and turn into AG1C. At the same time, the system will work as a reflux condenser and a significant part of the DHS (due to the reverse reaction with water) will return to the cube as an APS, and the distilled portion of the DHS will contain significant impurities of the APS. The minimum residence time of DGS vapors and water in the heating zone is provided by using conventional distillation apparatus in which the vapor separation efficiency is minimized, T1P.1e 1 is a unit of single-phase evaporation. DGS formed is easily removed from the peaj cyy zone due to the large difference in the boiling rates of the APS and DGS, Opt the brain separation speed and the yield of the system: (OKOLOO0%) reached fiiggs at a ratio of) aer.hhnsk; : 1 respectively. An increase in the reflux zone and, consequently, an increase in the duration of contact between the DHS vapor and water lead to their interaction with the formation of APS and the cessation of distillate release. That increase in the ratio of the surface of the reflux and the evaporation surface to 5: 1 while maintaining all other synthesis conditions leads to a 2-fold decrease in the rate of release of DHS (from 14.9 g / h to 7.4 g / h) .. DGS azeotrope — water boils at 72, C APS is charged to the distillation cube (at least of M of Ma) and then, as the distillate is distilled off, APS is added in order to maintain a constant level of liquid in the cube. The rate of nitrogen is maintained at 2–4 volumes of gas per unit volume of the bottom of the bottom of the tank per minute. The DHS with water is collected in a cooled collector. After the separation of the water layer, the optic layer is additionally subjected to azootropic re-1X) Nke for skisushki and a large, clean, dry DU. For example, a glass 4 burnt cube for the distillation of nodes with an atmospheric pressure of 9 O ml, equipped with a thermometer, a capillary for nitrogen supply, a dropping funnel and a glass reflux condenser with a working volume of 11 cm, load 48 g of APS (contain 96 , 9% of the main substance, and 3% of water. Surface reflux to the surface. Evaporation 1.7: 1. When the temperature increases in cubed to 19 ° C and nitrogen flow at a rate of 195. ml / min, the distillation of the diaze thermozeotrope van - water at a rate of 15 ml / h at a temperature in the vapor of 68-74 ° C. One The reaction mass is temporarily replenished with fresh APS at a rate equal to the heteroazeotrop selection speed, Experiment duration 4 hours. The contact time of dihydrosylvana and water in the vapor phase is 18 sec. The result is 59.5 g of heteroazetrop composition: DGS 75.6 weight,% water 24.4 wt.%, The yield of dihydrosylvana, calculated on the reacted APS, 93.5 wt.% Composition of the vat residue (47.5 g): APS 96.5 wt.%, Resin 2.7 wt. 9s., Water 0.8 wt.%. The degree of tar, considering the loaded APS 1.2%. The loss is 1%. From azeot -. The dihydrosylvan-water ropa separates the aqueous layer, and the organic layer is dried and then fractionated. Dedicated 4.5 dihydrSiwine iiNieeT: the following users: boilers, 79.3-80Х: / / 746 mm, Hg, Art., From 0.9018; q | ° 1.4351. EXAMPLE 2 The test was carried out in a flow system using the apparatus described in Example 1. The reaction mass was taken from the bottom of the cube, cooled in a refrigerator (refrigerant — water) and collected in a receiver. The speed, -feeding with raw materials is equal to the sum of the rates of selection of the heteroazeotrop and bottom product. The system is brought to a stationary mode within 3-3.5 hours. In a cube, 89 g of the technical APS containing 65.9 g (74.1%) of the main water, 1.8 g (2 г0%) of water and 21.3 g (23.9%) of resinous impurities. Feed raw materials evenly at a speed of 5 mol / h. The duration of the contact of DTS vapor and water 12 with the ratio of the reflux surface and the evaporation surface is 1.57. The duration of the experiment is 15 hours. At a cube temperature and a vapor temperature, nitrogen velocity O ml / min, an altropic DGS-water is taken in an amount of 70.6 g. In addition, during the synthesis process, 29.2 cubic meters of product containing 14.3 g (49 , 3 wt.%) APS, 1.0 g (3.2 wt.%) Of water and 13.9 g (47.5 wt.%) Of impurities, and in a cube there remains 64.2 g of a product of the same composition (t Ie 31.7 g APS, AOR, 5 g of resin and 2.0 g of water). If necessary, a cubed product is used in recycling. After separation of the azeotro, 53.6 g of DGS,, 435 O are separated in drying. The purity of the product is confirmed; (gives with IR spectra; The yield of dihydrosylvana, calculated on converted APS, is 89.5%; the degree of tarring of the raw material is 2.2%; Example 3. The test is carried out on the board described in example 2, in continuous nomime. 54 g of technical APS containing 13 g (24%) of APS, 34.2 g (63.2%) -butyrolactone, 2.0 g (3.8%) of acetone (0), 3g (0.6%) of water and 4.5 (8.4%) of the resin are loaded into cubic water. The feed with the same composition is applied evenly at a rate of 1 O, 8 ml / h. Duration 11.5 hours. The rate of nitrogen supply is 155 ml / h, the volume of the deflagration zone is 24.5 cm, the pace The cube structure is 190 ° C, the temperature in the vapor, the contact duration of the DHS vapor and water is 18 s, the ratio of the surfaces of deflamation and evaporation is 2: 1. During the experiment, 36 g of the heteroazeotrope and 142 g of the bottom product are collected (53 g in the cube residue) composition: APS 3.8 wt.%, butyrolactone and acetopropyl acetate 83.2 wt.%, water 1.7 wt.% and resin. Pitch tar of the raw material is 2.6%. After processing the heteroazeotrope, 27.2 g are obtained 4 5-dihydrosylvana 0.9023; Pl ° 1.4352. The purity of the product is confirmed by IR spectra. The output of DGS, counting on the reacted DGS, 86.5%. The technical methods of the proposed method are very simpler than the technology of the known, method. DGS obtained from in one apparatus both in a periodic and in a continuous pattern, use the vat residue for repeated downloads (i.e., recycle) in order to extract the dihydrosum completely as completely as possible without any additional processing. Operations to neutralize acidic impurities, in contrast to the known method, are absent, which excludes co-operation of technological equipment and the neutralization of production wastes. The proposed method gives the opportunity to reduce the number of stages of the process, reduce equipment costs. Claims The method of obtaining 4,5-dip1-drosilvana by dehydrating tG-acetopropyl alcohol at 190-2O3 ° C with subsequent separation of 4,5-digesive vapors and water, distilling, cooling "and separating the OO o product from the azeotrope, characterized by The goal is to optimize the process, the latter being conducted in a stream of inert gas, the rate of which is 1-5 volumes per minute per 1 volume of U-acetopropyl alcohol, with a duration of 4,5-dihydroshane vapor and water 10-ZO c. Sources of information accepted by all attention during the examination 1. USSR author's certificate 9 405856, cl. C O7 C 49/17, 1973 prototype).