SU1759827A1 - Method of producing 3-methyl-3-buten-1-ol - Google Patents

Abstract

Essence: production of 3-methyl-3-butene-1-ol by splitting oxygen-containing products of a high-boiling fraction of by-products of dimethyl dioxane production from isobutylene and formaldehyde, obtained by distillation at 60-130 ° C 0.97. Conditions: catalyst - 0.1-0.3% of phosphoric acid on aluminum gel, temperature 160-200 ° C, feed rate of the initial reagent 0.2-0.8. 5 tab., 3 Il.

Description

The invention relates to an improved process for the production of 3-methyl-3-buten-1-ol, which is used in the synthesis of dimethylvinyl carbinol, isoamyl alcohol, in the perfume industry,

A known method for producing 3-methyl-3-butene-1-ol (isobutenyl carbinol - IBC) as a by-product in the production of isoprene at the stage of decomposition of dimethyl dioxane on a calcium phosphate catalyst at 320-350 ° C. 2-3% IBh is formed in the oil layer, which is released by multiple rectification 1.

The disadvantages of this method are the low IBC yield and the complexity of its isolation.

A known method for producing IBC by thermal condensation of isobutylene with para-form at 150–200 ° C in glacial acetic acid or in anhydrous acetic anhydride 2.

The disadvantages of this method are the use of corrosive acetic acid and acetic anhydride,

multi-stage process and its low selectivity (less than 30%).

There is also known a method for producing IBC by catalytic condensation of isobutylene with paraform in an anhydrous medium in the presence of the Friedel-Crafts catalyst (zinc, tin, silicon chlorides) 3.

The disadvantages of this method are the same as in thermal condensation, in addition, the use of highly corrosive catalysts. The output of IBK does not exceed 30%.

Closest to the invention is a method for producing IB by decomposing 4,4-dimethyl-1,3-dioxane (DMD) with acetic anhydride in the presence of concentrated sulfuric acid 4 as a catalyst.

The process includes the following stages: obtaining a mixture of acetates; the stage of isolation of acetate IB; decomposition of acetate IB; isolation and purification of IB;

The disadvantages of this method is a multistage process, as well as applied

with

4 SL U 00

Yu

as a raw material, DMD and acetic anhydride, which leads to an increase in the cost of the product; use as a catalyst for sulfuric acid and the selection in the reaction of acetic acid, which creates an increased corrosive environment; obtaining in the second stage of the process an acetate solution that is not disposed of and forms a large amount of salt effluent.

The purpose of the invention is to simplify the process and improve its economic performance.

The goal is achieved by the proposed method of obtaining IBS by splitting the Fraction obtained by vacuum distillation of high-boiling by-products (WFP) produced by DMD through isobutylene and formaldehyde on the catalyst — phosphoric acid deposited on the aluminum gel, in an amount of 0.1–0.3 wt.% With the temperature of 160-200 ° C and the flow rate of the feed fraction of 0.2-0.8,

The composition of the runway fraction, isolated by vacuum distillation of the runway of DMD synthesis in the temperature range 60-130 ° C at a pressure of 0.97 at (200-220 ° C at atm. Pressure), includes the following components, wt.%:

4,4-Dimethyl-1,3-dioxane + + 4-vinyldioxane-1.34.9-5.8

Methyl butanediol esters (MOI) 36.5-37.3

Piran alcohol 28,5-29,5

MBD21.5-22,7

Dioxane alcohol ethers (methanol and 4-methyl-4-oxyethyl-1,3-dioxane and 3-methylcarbinol and 4-methyl-4oxyethyl-1, 3-dioxane) 5,6-7,5

The fraction obtained by vacuum distillation of the runway for the synthesis of DMD at temperatures higher than that proposed (from 60 to 140 ° C and a pressure of 0.97 ata), in addition to the components of the proposed fraction, includes dioxane alcohol, the content of dioxane alcohol ethers, which decompose with release formaldehyde, and he entered into a reaction with IBK, forms pyran and secondary runways. which leads to lower output IB and faster deactivation of the catalyst.

When using the fraction obtained by vacuum distillation of runway synthesis at temperatures below the proposed (from 60 to 120 ° C, pressure 0.97 atm), the content of MBD decreases and, as a result, IBC output decreases.

The compositions of the fractions obtained by vacuum distillation of the runway of DMD synthesis are listed in Table 1. These fractions were decomposed on a catalyst — 0.2% phosphoric acid on alumina (TU 38.103190-80) at a temperature of 180 ° С and a bulk feed rate of 0 ,five . The dependence of the output of IBC is illustrated by examples 16-21.

The significance of the proposed phosphoric acid concentration on aluminum gel is related to the fact that at a phosphoric acid concentration of 0.1–0.3%, the IBC yield is maximum.

With a decrease in the concentration of phosphoric acid below 0.1%, the yield of IBC decreases as the activity of the catalyst decreases. With an increase in the concentration of phosphoric acid above 0.3%, a decrease in the IBC yield is also observed, which is due to the intensification of the IBC dehydration process to isoprene.

The dependence of IB output on the concentration of phosphoric acid is shown in Table 2, is graphically displayed in Figure 1 and is illustrated in Examples 1-5.

5 As can be seen from the graph of the dependence of KT activity and the selectivity of the process on IBC on the concentration of phosphoric acid, with an increase in the concentration of phosphoric acid on the aluminum gel, the KT activity increases and the selectivity decreases. The optimum concentration of phosphoric acid on alumina is 0.1-0.3%.

The significance of the proposed temperature range is due to the fact that when the temperature decreases below 160 ° C, the catalyst activity drops to 11.7% and, as a result, the IBC output decreases, despite the unchanged catalyst selectivity (42.6%). With the rise

0 above the proposed temperature (more than 200 ° C), a decrease in the selectivity of the IBC process (up to 15.5%) is observed, since the IBC dehydration process to isoprene is intensified.

5 The dependence of the output of IB on temperature is given in table 3. The dependence of the activity of the catalyst and the selectivity of the process on the IBD on the temperature is displayed graphically in FIG. 2, Starting from the graph of the dependence of the selectivity of the process on the IBD and the activity of the catalyst on the temperature, the optimal decomposition temperature is 160-200 ° C. This process is illustrated with examples of € -10.

5 The significance of the proposed interval of the feed rate of raw materials is due to the fact that with an increase in the flow rate above 0.8, the output of the IBC falls due to the shortening of the contact time. With a decrease in the space velocity of less than 0.2 h 1, the contact time increases so much that dehydration of the pulp and paper mill to isoprene occurs and, as a result, the selectivity of the IBC process decreases.

The dependence of the output of IB on the flow rate is given in table 4. The dependence of the activity of the catalyst and the selectivity of the process on the IBC from the volumetric feed rate of the raw material is graphically displayed in FIG. It can be seen that the optimal volumetric rate of the proposed process is 0.5. This process is illustrated by examples 11-15.

Example 1. In a flow type reactor heated by an electric furnace, 50 ml of catalyst is charged — 0.05% of NZROp on alumina prepared using the following procedure: 50 ml of aluminogel previously calcined at 250 ° C for 2 h are poured into 100 ml 0.7 % phosphoric acid solution. The aluminum gel is kept in a solution of phosphoric acid for 3 hours, after which the impregnating solution is drained. The impregnated aluminogel is pre-dried at 80-90 ° C for 2 hours. It is then calcined at 250 ° C for 2 hours.

By applying voltage to the heater, the temperature on the catalyst is raised to 180 ° C. Upon reaching this temperature, a metering pump with a bulk velocity of 0.5 serves a runway fraction of the following composition, wt.%:

DMD + VD5,8

Ethers MBD36,5

Piran alcohol28,5

MBD21.5

Ethers of dioxane alcohol 7.5 Catalysate collected in the receiver and subjected to chromatographic analysis. According to the results of chromatographic analysis, the activity of the catalyst and the selectivity of the process by IBC are determined. Data on activity and selectivity are given in table 2.

The catalytic product was isolated as follows. Boric acid is added at the rate of 0.7 mol of boric acid per 1 mol of IBC. While boiling with a Dean-Stark nozzle, water is distilled off, the residue is distilled under vacuum. 2 volumes of water are added to the residue and after a half-hour boiling the azeotrope of IBC is distilled with water. IBC output 98%.

Example 2. In the reactor of example 1 load the catalyst - 0.1% NSRM on aluminum gel, prepared according to the same method as in example 1. The temperature on the catalyst, the composition and volume rate

filing fractions are the same as in example 1 Chromatographic data are given in table 2.

Example 3. In the reactor of example 1, load the catalyst - 0.2% NSRM on aluminum gel, prepared according to the same method as in example 1. The temperature on the catalyst, the composition and volumetric feed rate of the fraction are the same. that in example 1. Chromatographic data are given in table 2.

Example 4. In the reactor of example 1 load catalyst - 0.3% NzR04 on alumina, prepared according to the same method as in example 1. The temperature on the catalyst, the composition and volumetric feed rate of the fraction are the same as in example 1. Chromatographic data are shown in table 2.

Example 5. In the reactor of example 1 load catalyst - 0.4% NzRO on alumina, prepared according to the same method as in example 1. The temperature on the catalyst, the composition and volumetric feed rate of the fraction are the same as in example 1. Chromatographic data are shown in table 2.

Example 6. A continuous type reactor is charged with 50 ml of catalyst — 0.2% HzRO on alumina. When the temperature on the catalyst reaches 150 ° C, the fraction is started to flow at a volumetric rate of 0.5 vol. The composition of the fraction is the same as in example 1. The catalyst is collected in the receiver and subjected to chromatographic analysis. Data chromatographic analysis are given in table.3.

Example 7. The volumetric rate, the composition of the raw materials and the catalyst are the same as in example 6. The temperature on the catalyst is 160 ° C. Data chromatographic analysis are given in table.3.

Example 8. The volumetric rate, the composition of the raw materials and the catalyst are the same as in example 6. The temperature on the catalyst is 180 ° C. Data chromatographic analysis are given in table.3.

Example 9. The volumetric rate, the composition of the raw materials and the catalyst are the same. that in example 6. The temperature on the catalyst 200 ° C. Data chromatographic analysis are given in table.3.

Example 10. The volumetric rate, the composition of the raw material and the catalyst are the same as in example 6. The temperature on the catalyst is 210 ° C. Data chromatographic analysis are given in table.3.

Example 11. A continuous type reactor was charged with 50 ml of catalysaurel — 0.2% HzP04 on alumina. Upon reaching a temperature of 180 ° C, the feed of the former composition with a bulk velocity of 0.1 is started. The catalyst is collected in the receiver and subjected to chromatographic analysis. These chromatographic analysis are shown in table 4,

Example 12. The temperature, the composition of the feedstock and the catalyst are the same as in example 11, the volumetric feed rate is 0.2. Data chromatographic analysis are given in table.4.

Example 13. The temperature, the composition of the raw material and the catalyst are the same as in example 11. The volumetric feed rate of 0.5 vol. Data chromatographic analysis are given in table.4.

Example 14. The temperature, the composition of the feedstock and the catalyst are the same as in Example 11. The volumetric feed rate is 0.8 vol. Data chromatographic analysis are given in table.4.

Example 15. The temperature, the composition of the feedstock and the catalyst are the same as in example 11. The volumetric feed rate is 1.0 vol. Data chromatographic analysis are given in table.4.

Example 16 Into a continuous-type reactor, 50 ml of catalyst are charged —0.2% HzP04 on alumina. Upon reaching a temperature of 180 ° C, start the flow of fraction 1 with a bulk velocity of 0.5. The composition of the fraction isolated by vacuum distillation of the runway synthesis of DMD is given in table 1. The catalyst is collected in the collection and subjected to chromatographic analysis. According to the results of chromatographic analysis, the selectivity of the process by IBC and the activity of the catalyst are determined. Data on selectivity and activity are given in table.1.

Example 17. The temperature, catalyst and feed rate are the same as in example 16. The composition of fraction 2 is shown in table 1.

Example 18. The temperature, catalyst and feed rate are the same as in example 16. The composition of fraction 3 is given in table 1.

Example 19. The temperature, catalyst and feed rate are the same as in

Example 16. The composition of fraction 4 is shown in Table 1.

Example 20. The temperature, catalyst and feed rate are the same as in

example 16, the composition of fraction 5 is given in table.1.

Example 21. The temperature, catalyst and feed rate are the same as in example 16. The composition of fraction 6 is given in

table.1.

The procedure for isolating IBs is given in Example 1.

Table 5 shows the material balance of the decomposition processes.

Thus, the optimal conditions for the proposed method of obtaining IBS are the space velocity of 0.2-0.8 decomposition process temperature of 160-200 ° C; raw material is a fraction obtained by

vacuum rectification of the runway for the synthesis of DMD in the temperature range of 60-130 ° C and at a pressure of 0.97 eta; catalyst - 0.1-0.3% NzROCH on technical alumogel.

The proposed method is one-step, in

The quality of the starting product is the use of dimethyl dioxane production, it does not require the use of acetic anhydride and sulfuric acid. The known method has four stages, as the source

product use pure DMD, method

requires the use of acetic anhydride.

Claims (2)

Invention Formula The method of obtaining 3-methyl-3-butene-1ola by splitting oxygen-containing compounds in the presence of a heterogeneous acid catalyst at elevated temperatures, characterized in that, in order to simplify the process and improve its economic performance, as oxygen-containing compounds use oxygen-containing products of a high-boiling fraction of by-products from the production of dimethyldioxane from isobutylene and formaldehyde, obtained by distillation in the range of 60-130 ° С at 0.97 eta. Phosphoric acid on an aluminum gel with a phosphoric acid content of 0.1–0.3 wt.% is used as a catalyst, and the process is carried out at a temperature of 160–200 ° C and the feed supply rate increases of 0.2–0.8. Table 1 Dependence of the activity and selectivity of the 8PP decomposition process on the composition of the fraction at the temperature and bulk flow rate of the raw material 0.5 Note. R ablits T.O. includes the components supplied to the decomposition of the ra to c yygkotyyyus talys: Dependence of catalyst composition on temperature Table The material balance of decomposition processes at a temperature of 1 ° C, a space velocity of 0.5, a catalyst — 0.2%, raw materials — fraction 2 soto thirty 20 iu 0,0, 2.O.O.CH % C on AG2Oz FigL yo ,P 60 40 go 90 # i 60 50