RU2451662C1 - Method of producing tertiary butyl alcohol - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: proposed method relates to production of tertiary butyl alcohol used as semi-product in organic synthesis for production of isobutylene and isoprene. Proposed method consists in liquid-phase reaction of isobutylene or isobutylene-containing hydrocarbon mix with water at increased temperatures and pressure in presence of tertiary butyl alcohol as solvent with initial stock straight flow feed into column reactor filled with layers of sulfonic cation(-exchange) resin catalyst with subsequent extraction of target product from produced reaction mix. Note here that mixed catalyst is used consisting of fresh catalyst and catalyst used, at least, 800 hours in this process at ratio of (1-5): 1, respectively. Normally, process temperature makes 60-100°C at pressure of 14-25 atm.

EFFECT: reduced yield of byproducts, longer life of catalyst.

2 cl, 5 ex

Description

The invention relates to the field of petrochemistry, and more specifically to methods for producing tertiary butyl alcohol (TBS), which is used as an intermediate in organic synthesis, in particular for the production of isobutylene and isoprene, used in the production of butyl rubber and isoprene rubber.

A known method of producing TBS by the liquid-phase reaction of isobutylene in the form of an isobutylene-containing hydrocarbon fraction with water at a temperature of 80-90 ° C with a countercurrent flow of feeds of the initial reagents into a column reactor filled with a sulfocationite catalyst. Water and the isobutylene-containing fraction are supplied at a volume ratio of (7-10): 1, which corresponds to a molar ratio of water: isobutylene (80-110): 1. The resulting TBS is removed from the reactor as part of two reaction streams, which are a dilute solution of TBS in hydrocarbons and a dilute solution of TBS in water. The productivity of the process is 100 g of isobutylene per 1 liter of catalyst per hour. From the obtained TBS solutions are isolated by distillation [S.Yu. Pavlov. Isolation and purification of monomers for synthetic rubber. L .: Chemistry, 1987, p.133-136].

The disadvantage of this method is the low rate of hydration reaction due to the mutual insolubility of the starting reagents, as well as the complexity of the technology and increased energy costs associated with the allocation of TBS from two diluted solutions.

A known method for producing TBS by the liquid-phase reaction of isobutylene in the form of an isobutylene-containing hydrocarbon fraction with water at a temperature of 70-110 ° C with a direct-flow feed of the feed of the reactants into a vertical reactor filled with a sulfocationite catalyst. Water and isobutylene are supplied at a molar ratio of (5-20): 1. To increase the mutual solubility of the reagents, the hydration reaction is carried out in the presence of a homogenizer - a polar solvent of ethyl cellosolve in an amount of 10-70% of the mass. to water and a nonionic emulsifier. The productivity of the isobutylene process is 150-170 g / l · h. TBS is isolated by distillation from the obtained reaction mixture [SU 512622, 01/30/1983].

The disadvantage of this method is the formation of undesirable by-products from the solvent with the participation of TBS, the complexity of the technology and the increased energy costs associated with the allocation of TBS from a dilute mixture with water and ethyl cellosolve.

Closest to the claimed is a known method for producing TBS by a liquid-phase reaction of isobutylene or an isobutylene-containing hydrocarbon mixture with water at a temperature of 30-110 ° C, preferably 50-90 ° C, with a direct-flow feed of the starting reagents into a reactor filled with a sulfocationic catalyst. Preferably, 2-5 series reactors are used. Reactors with a fixed catalyst bed are used with uniform loading of the amount of catalyst in each reactor / bed. To increase the mutual solubility of the reagents, the hydration reaction is carried out in the presence of TBS as a solvent in an amount of 21.6-78% of the mass. in the reaction zone. The productivity of the isobutylene process is 160-200 g / l · h. From the obtained reaction mixture TBS is isolated by distillation [US 4307257, 12/22/1981 - prototype].

The disadvantage of this method is the conversion of about 1% of isobutylene into by-products - isobutylene dimers and oligomers, which complicate the isolation of TBS and impair its quality. Another disadvantage is the decrease in catalyst activity and isobutylene productivity below 130 g / l · h after 6-8 thousand hours of operation of the process. After this period, the entire catalyst is discharged from the reactor and replaced with a fresh portion, which complicates the technology and increases production costs.

The objective of the proposed method is to reduce the yield of by-products and increase the life of the catalyst in the reactor while maintaining the performance of the process for producing TBS.

This problem is solved by the method of obtaining TBS by a liquid-phase reaction of isobutylene or isobutylene-containing hydrocarbon mixture with water at elevated temperature in the presence of TBS as a solvent with direct-flow feed of the starting reagents into a column reactor filled with layers of sulfation cation catalyst, followed by isolation by rectification of the target product from the obtained reaction mixture. In each catalyst layer there is a mixture of fresh catalyst and a catalyst that has spent at least 8 thousand hours in the same process, with a volume ratio of (1-5): 1, respectively.

As isobutylene feedstock, concentrated isobutylene containing 90.0-99.9% of isobutylene or isobutylene-containing hydrocarbon fractions with different isobutylene contents, in particular industrial butylene-isobutylene or isobutane-isobutylene fractions containing 10-60% isobutylene, are used.

The catalyst used is cation exchange resins in the H-form, in particular cation exchangers based on sulfonated copolymers of styrene and divinylbenzene. Macroporous sulfocathionites, in particular KU-23, Duolite C26, Amberlyst 15, Lewatit K2629, Dowex 50, Purolite CT275, are preferably used.

The process is carried out using one or more series-parallel or parallel-connected column reactors (vertical cylindrical apparatus) filled with a catalyst. The catalyst in the reactor is arranged in the form of layers, the number of which is at least 2, preferably 3-5. The catalyst is loaded quantitatively into each layer uniformly and / or unevenly. In each catalyst layer, the volume ratio of the portions of fresh catalyst and the catalyst that spent at least 8 thousand hours in the same process is (1-5): 1.

Water and isobutylene feed are fed into the reactor by direct flow from top to bottom or from bottom to top with a molar ratio of (1-4): 1, respectively. The flow of water for the reaction is carried out on one or separately several layers of catalyst.

The hydration reaction is carried out at a temperature of 60-100 ° C and a pressure of 14-25 atm, sufficient to maintain the products of the reaction mixture in the liquid phase. To control the temperature in the reactor, it is possible to cool the reaction stream between the catalyst layers in external heat exchangers.

The reaction is carried out in the presence of TBS as a solvent with its content in the reaction zone of 20-60% of the mass. The indicated TBS content is provided by recycle of a portion of the obtained TBS and / or by recycle of a portion of the reaction mixture containing TBS coming out of the reactor to the reactor inlet, as well as feeding TBS obtained in another process to the reactor. The supply of TBS to the reactor is carried out as part of a water stream for the reaction and / or a stream of isobutylene feed, as well as in a separate stream.

Salient features of the proposed method is the process using a mixed catalyst consisting of fresh catalyst and a catalyst that has spent at least 8 thousand hours in the same process, with a volume ratio of (1-5): 1, respectively.

The proposed method allows to reduce the yield of by-products to below 0.3%, to increase the life of the catalyst in the reactor to 13-15 thousand hours while maintaining the performance of the process.

The industrial applicability of the proposed method is confirmed by the following examples.

Example 1

In the reactor, which is a vertical metal pipe made of 12X18H10T steel with an inner diameter of 10 mm and a length of 1400 mm, 72 ml of mixed sulfocationic catalyst are loaded, which are arranged in the form of three layers of 24 ml.

Each catalyst layer contains 18 ml of fresh Purolite CT275 catalyst (particle size 0.3-1.2 mm, static exchange capacity of 5.2 mEq H ⁺ per 1 g of dry catalyst) and 6 ml of a catalyst of the same brand, which is already was used in the same process for 10 thousand hours. The volume ratio of portions of fresh and spent catalyst in the layer is 3: 1.

At the top of the reactor serves as isobutylene feedstock hydrocarbon mixture containing 45.0% of the mass. isobutylene (the rest isobutane, n-butane and n-butenes up to 100), with a speed of 36.3 g / h. Together with isobutylene feed water is supplied at a speed of 6.6 g / h and a recycle stream containing 90.61% of the mass. TBS, 9.22% water and 0.17% isobutylene dimers, at a rate of 24.5 g / h.

The process is carried out at a temperature of 60-65 ° C, a pressure of 14-15 atm.

From the bottom of the reactor, the reaction mixture is withdrawn at a rate of 67.4 g / h and fed to a distillation column to isolate TBS. Unconverted hydrocarbons are distilled off at the top of the column at a rate of 21.8 g / h. The content of isobutylene in the distillate is 8.4% of the mass.

VAT liquid distillation column in the amount of 45.6 g / h contains 90.61% of the mass. TBS, 9.22% water and 0.17% isobutylene dimers. A portion of this bottoms liquid in an amount of 24.5 g / h is returned to the reactor. The rest of the amount of 21.1 g / h is removed from the process and then used, in particular, as a raw material for the production of isoprene.

The conversion of isobutylene in the process is 88.8%, the isobutylene productivity is 201 g / l · h, the yield of isobutylene dimers is 0.25%. During 14.5 thousand hours of continuous operation, process indicators do not change.

Example 2

The process is carried out analogously to example 1, however, there are the following differences.

Each catalyst layer contains 20 ml of fresh catalyst and 4 ml of catalyst spent over 11 thousand hours. The volume ratio of portions of fresh and spent catalyst is 5: 1. In the reactor, the temperature is 65-70 ° C, the pressure is 15-16 atm.

The conversion of isobutylene in the process is 86.7%, the productivity of isobutylene is 196 g / l · h, the yield of isobutylene dimers is 0.25%. For 14 thousand hours of continuous operation, process indicators do not change.

Example 3

The process is carried out analogously to example 1, however, there are the following differences.

Each catalyst layer contains 16 ml of fresh catalyst and 8 ml of catalyst spent over 9 thousand hours. The volume ratio of portions of fresh and spent catalyst is 2: 1. In the reactor, the temperature is 75-80 ° C, pressure 16-17 atm.

The conversion of isobutylene in the process is 83.1%, the productivity of isobutylene is 188 g / l · h, the yield of isobutylene dimers is 0.2%. During 15 thousand hours of continuous operation, process indicators do not change.

Example 4

The process is carried out analogously to example 1, however, there are the following differences.

Each catalyst layer contains 12 ml of fresh catalyst and 12 ml of catalyst spent over 8 thousand hours. The volume ratio of portions of fresh and spent catalyst is 1: 1. In the reactor, the temperature is 93-100 ° C, pressure 23-25 atm.

The conversion of isobutylene in the process is 80.6%, the productivity of isobutylene is 183 g / l · h, the yield of dimers is 0.3%. During 13 thousand hours of continuous operation, process indicators do not change.

Example 5

In the reactor, which is a vertical metal pipe made of 12X18H10T steel with an inner diameter of 10 mm and a length of 1400 mm, 80 ml of mixed sulfocationic catalyst are loaded, which are arranged in four layers of 20 ml.

Each catalyst bed contains 12 ml of fresh Lewatit K2629 catalyst (particle size 0.4-1.2 mm, SOE 5.0 mEq / g) and 8 ml of the same grade of catalyst that was already used in the same process. over 9 thousand hours. The volume ratio of portions of fresh and spent catalyst in the layer is 1.5: 1.

Concentrated isobutylene containing 99.0% by weight of isobutylene (the rest isobutane, n-butane and n-butenes up to 100) is fed to the bottom of the reactor as isobutylene feedstock at a rate of 48.9 g / h. Together with isobutylene feed water is supplied at a speed of 19.6 g / h and a recycle stream containing 88.28% of the mass. TBS, 11.52% water and 0.20% isobutylene dimers, at a rate of 67.5 g / h.

The process is carried out at a temperature of 80-85 ° C, a pressure of 18-19 atm.

From the top of the reactor, the reaction mixture is withdrawn at a rate of 136.0 g / h and fed to a distillation column to isolate TBS. Unconverted hydrocarbons are distilled off at the top of this column at a rate of 9.1 g / h. The content of isobutylene in the distillate is 94.6% of the mass.

The distillation column bottoms liquid in an amount of 126.9 g / h contains 88.28% of the mass. TBS, 11.52% water and 0.20% isobutylene dimers. A portion of this bottoms liquid in an amount of 67.5 g / h is returned to the reactor. The remainder in the amount of 59.4 g / h is removed from the process and then used, in particular, as a raw material for the production of isoprene.

The conversion of isobutylene in the process is 82.2%, the productivity of isobutylene is 497 g / l · h, the yield of isobutylene dimers is 0.3%. During 13.5 thousand hours of continuous operation, process indicators do not change.

Claims (2)

1. A method of producing tertiary butyl alcohol by a liquid-phase reaction of isobutylene or an isobutylene-containing hydrocarbon mixture with water at elevated temperature and pressure in the presence of tertiary butyl alcohol as a solvent with a direct-flow feed of the starting reagents into a column reactor filled with layers of a sulfation cation catalyst, followed by isolation of the rectification of the target product from the resulting reaction mixture, characterized in that the process is carried out using a mixed catalyst, with standing of the fresh catalyst and the catalyst, the exhaust of at least 8000 hours in the same process at a volume ratio of (1-5): 1, respectively. 2. The method according to claim 1, characterized in that the process is carried out at a temperature of 60-100 ° C, a pressure of 14-25 atm.