阅读说明：本技术 制备卤化异丁烯-异戊二烯橡胶的工艺 (Process for preparing halogenated isobutylene-isoprene rubber ) 是由 J·P·沃拉 于 2018-04-09 设计创作，主要内容包括：本发明涉及橡胶领域。通过将异戊二烯单体和异丁烯单体聚合,然后用卤化剂进行卤化,制备卤化异丁烯-异戊二烯橡胶。本发明的工艺是简单的、节能的和经济的。(The invention relates to the field of rubber. Halogenated isobutylene-isoprene rubber is prepared by polymerizing isoprene monomers and isobutylene monomers, followed by halogenation with a halogenating agent. The process of the invention is simple, energy-saving and economical.)

1. A process for preparing a halogenated isobutylene-isoprene rubber, the process comprising:

a. Polymerizing isoprene monomer with isobutylene monomer in a first fluid medium to obtain a first product dough comprising isobutylene-isoprene rubber;

b. Adding an alcohol to the first product mass to quench the polymerization, thereby obtaining a first product mass;

c. Adding a second fluid medium to the first resultant mass, thereby obtaining a second resultant mass;

d. Adding water to a second resultant mass with continuous stirring, allowing the second resultant mass to stand, thereby obtaining a two-phase mixture comprising an organic phase and an aqueous phase, wherein the organic phase comprises isobutylene-isoprene rubber, a first fluid medium, unreacted isobutylene monomer, unreacted isoprene monomer, and a second fluid medium, and the aqueous phase comprises an alcohol;

e. Separating the organic phase from the biphasic mixture;

f. Fractionating the separated organic phase to obtain a bottom fraction comprising isobutylene-isoprene rubber and a second fluid medium;

g. Adding a halogenating agent to the bottom fraction and stirring, thereby obtaining a second product group comprising a crude mixture comprising halogenated isobutylene-isoprene rubber; and

h. The crude mixture is subjected to the steps of washing, stripping and drying, thereby obtaining a halogenated isobutylene-isoprene rubber.

2. The process of claim 1, wherein the step of polymerizing comprises:

i. Introducing isoprene monomer and at least one first fluid medium into a reactor, thereby obtaining a first mass;

Cooling the first mass to a predetermined low temperature, thereby obtaining a cooled first mass; and

introducing isobutylene monomer into the reactor and agitating the reaction mass while maintaining a predetermined low temperature, thereby obtaining a first product mass comprising isobutylene-isoprene rubber.

3. The process of claim 1, wherein step (a) is optionally carried out in the presence of a catalyst selected from the group consisting of diethylaluminum chloride and ethylaluminum dichloride.

4. the process of claim 1 or 2, wherein the first fluid medium is selected from at least one of the group consisting of ethyl chloride, isopentane, and hexane.

5. The process of claim 1, wherein the alcohol is at least one selected from the group consisting of methanol and ethanol.

6. The process according to claim 2, wherein the predetermined low temperature is in the range of-40 ℃ to-80 ℃.

7. The process of claim 1, wherein the second fluid medium is at least one selected from the group consisting of hexane and isopentane.

8. The process of claim 1, wherein the fractionating step is at a temperature in the range of 30 ℃ to 150 ℃, 3kg/cm²To 8kg/cm²Is carried out in the pressure range of (1).

9. The process of claim 1 wherein the halogenating agent is selected from the group consisting of bromine (Br)₂) And at least one of the group consisting of chlorine gas。

10. The process according to claim 1, wherein the washing step is carried out with at least one alkaline solution selected from the group consisting of sodium hydroxide, potassium hydroxide and sodium bis-salicylate.

Technical Field

The invention relates to the field of rubber.

Definition of

As used herein, the following terms generally have the following meanings, except where otherwise indicated in the context in which they are used.

Bottom fraction: in the fractionation process, a portion or portions of the mixture are distilled from the fractionation unit and collected as an overhead fraction, while another portion of the mixture is not distilled and continues to remain in the fractionation unit. The undistilled portion of these mixtures exits the lowermost end of the fractionation column and is referred to as the "bottoms fraction".

Background

Halogenated isobutylene-isoprene rubber has various curing systems, and better heat resistance. Therefore, halogenated isobutylene-isoprene rubbers are widely used in various applications, such as the preparation of tire innerliners for tubeless tires, rubber stoppers for medical use, heat-resistant conveyor belts, and the like.

The process for preparing halogenated isobutylene-isoprene rubber involves two reactions, the first reaction being the polymerization to give isobutylene-isoprene rubber and the second reaction being its halogenation. The conventional process for preparing halogenated isobutylene-isoprene rubber is complicated and involves many steps. Typically, after polymerization, the isobutylene-isoprene rubber is separated in the form of chips by stripping. The stripping step separates the isobutylene-isoprene rubber from impurities and the fluid medium used for polymerization. The separated isobutylene-isoprene rubber fragments need to be dissolved in a suitable fluid medium prior to the halogenation step. The conventional process results in higher operating and labor costs due to the stripping separation step and the step of dissolving in a suitable fluid medium. Further, the separation step of stripping requires high energy. Furthermore, stripping produces waste water, which requires sewage treatment. Furthermore, the amount of fluid medium used is also high due to the use of separate fluid media for polymerization and halogenation.

Therefore, the conventional process has drawbacks such as complicated process, high energy consumption, high cost, and high usage of the fluid medium.

Accordingly, there is a need to provide a simple process for preparing halogenated isobutylene-isoprene rubber that is energy efficient, economical and uses a relatively small amount of fluid medium.

target

Some of the objects of the present invention are met by at least one embodiment herein, as described below.

It is an object of the present invention to ameliorate one or more of the problems of the prior art, or at least to provide a useful alternative.

It is an object of the present invention to provide a simple process for preparing halogenated isobutylene-isoprene rubber.

It is another object of the present invention to provide an energy-efficient and economical process for preparing halogenated isobutylene-isoprene rubber.

it is another object of the invention to provide a process that uses less fluid medium.

Other objects and advantages of the present invention will become more apparent from the following description, which is not intended to limit the scope of the present invention.

Disclosure of Invention

The present invention relates to a process for preparing halogenated isobutylene-isoprene rubber. The process comprises the following steps.

Isoprene monomer is polymerized with isobutylene monomer in a first fluid medium to obtain a first product mass comprising isobutylene-isoprene rubber.

The polymerization is quenched by adding an alcohol to the first product mass, thereby obtaining a first product mass (residual product mass). Adding a second fluid medium to the first resultant mass, thereby obtaining a second resultant mass.

Water is added to the second resultant mass under continuous stirring, and the second resultant mass is allowed to stand, thereby obtaining a two-phase mixture comprising an organic phase and an aqueous phase. The organic phase comprises isobutylene-isoprene rubber, a first fluid medium, unreacted isobutylene monomer, unreacted isoprene monomer, and a second fluid medium, and the aqueous phase comprises an alcohol. The organic phase was separated from the biphasic mixture.

The separated organic phase is fractionated to obtain a bottom fraction comprising isobutylene-isoprene rubber and a second fluid medium.

The isobutylene-isoprene rubber present in the bottom fraction is halogenated by adding a halogenating agent and stirring, thereby obtaining a second product group containing a crude mixture comprising halogenated isobutylene-isoprene rubber.

and washing, stripping and drying the crude mixed material to obtain the halogenated isobutylene-isoprene rubber.

Detailed Description

conventional processes for preparing halogenated isobutylene-isoprene rubbers are expensive, laborious, and involve many steps. Typically, after polymerization, the isobutylene-isoprene rubber is separated in the form of chips by stripping, which is performed to separate the isobutylene-isoprene rubber from impurities and the fluid medium of polymerization. The separated isobutylene-isoprene rubber is dissolved in a fluid medium prior to the halogenation step. The present invention contemplates a simple, energy-efficient, economical process using a relatively small amount of fluid medium.

In one aspect, the present invention provides a process for preparing a halogenated isobutylene-isoprene rubber, the process comprising the steps of:

Isoprene monomer is polymerized with isobutylene monomer in a first fluid medium to obtain a first product mass comprising isobutylene-isoprene rubber. The first product mass further comprises a first fluid medium, unreacted isobutylene monomer, and unreacted isoprene monomer.

the step of polymerizing comprises introducing isoprene monomer and at least one first fluid medium into the reactor, thereby obtaining a first dough. The first dough is cooled to a predetermined low temperature, thereby obtaining a cooled first dough. Introducing isobutylene monomer into the reactor and stirring the reaction mass while maintaining a predetermined low temperature, thereby obtaining a first product mass comprising isobutylene-isoprene rubber.

According to an embodiment of the present invention, the reaction mass further comprises at least one catalyst selected from the group consisting of diethylaluminum chloride and ethylaluminum dichloride.

The first fluid medium is at least one selected from the group consisting of ethyl chloride, isopentane, and hexane.

The predetermined low temperature is in the range of-40 ℃ to-80 ℃.

The cooled reaction mixture is stirred such that the isoprene monomers and isobutylene monomers polymerize to form the isobutylene-isoprene rubber. The isobutylene-isoprene rubber remains dissolved in the first fluid medium.

The polymerization is quenched by adding an alcohol to the first product mass, thereby obtaining a first product mass. Adding a second fluid medium to the first resultant mass, thereby obtaining a second resultant mass.

According to an embodiment of the present invention, the alcohol is at least one selected from the group consisting of methanol and ethanol.

According to an embodiment of the invention, the second fluid medium is at least one selected from the group consisting of hexane and isopentane.

According to an embodiment of the invention, the first fluid medium and the second fluid medium may be identical.

The second resultant mass comprises isobutylene-isoprene rubber dissolved in the first fluid medium along with impurities such as unreacted monomers and alcohols. The amount of impurities, such as unreacted monomers and alcohols, need to be reduced prior to halogenating the isobutylene-isoprene rubber.

Typically, the stripping step is performed in order to separate impurities from the fluid medium to obtain the desired purity of the isobutylene-isoprene rubber. However, the gas step is an energy intensive step. Further, the stripping step removes the fluid medium and provides the isobutylene-isoprene rubber in the form of rubber crumbs. However, the halogenation is carried out in the solution phase. Therefore, it is necessary to dissolve the isobutylene-isoprene rubber crumb in a fluid medium prior to the halogenation step. Thus, the conventional process requires more energy and more fluid medium.

In the present invention, impurities are removed by (i) washing with water to remove water-soluble impurities, and then (ii) fractionating to remove volatile impurities. The isobutylene-isoprene rubber of the desired purity obtained by the process of the present invention is present in the second fluid medium in the form of a solution. The solution can be used directly for halogenation.

Initially, water-soluble impurities are removed from the resultant mass with the aid of water.

The separating step comprises adding water to the second resultant mass and allowing the second resultant mass to stand with continuous stirring to obtain a two-phase mixture comprising an organic phase comprising isobutylene-isoprene rubber, the first fluid medium, unreacted isobutylene monomer, unreacted isoprene monomer and the second fluid medium and an aqueous phase comprising alcohol. When the polymerization is carried out in the presence of a catalyst, the aqueous phase also contains the catalyst in the separation step. The organic phase was separated from the biphasic mixture. The aqueous phase may be separated from the organic phase using a precipitator. The resultant mass is separated into an organic phase and an aqueous phase with the aid of water.

Finally, volatile impurities are removed from the separated organic phase by employing fractional distillation. Fractionating the separated organic phase to obtain a bottom fraction comprising isobutylene-isoprene rubber and a second fluid medium. The fractionated fraction comprises unreacted isobutylene monomer, unreacted isoprene monomer and the first fluid medium. A fractionated fraction comprising unreacted monomer and first fluid medium may be recovered.

The fractionating step may be at a temperature in the range of 30 ℃ to 150 ℃ and 3kg/cm²To 8kg/cm²is carried out in the pressure range of (1).

the conventional process includes a step of dissolving isobutylene-isoprene rubber chips obtained after the stripping step in hexane. The hexane-soluble isobutylene-isoprene rubber is halogenated in the halogenation step. In contrast, the process of the present invention avoids the step of dissolving isobutylene-isoprene. Overall, the process of the invention consumes less energy and less fluid medium. The unreacted monomer and fluid medium may be recycled to the first step of the polymerization. The process of the invention is therefore simple, energy-saving and economical.

The isobutylene-isoprene rubber present in the bottom fraction is halogenated by adding a halogenating agent and stirring, thereby obtaining a second product group comprising a crude mixture comprising halogenated isobutylene-isoprene rubber and a second medium fluid.

In embodiments of the invention, the halogenating agent is selected from the group consisting of bromine (Br)₂) And chlorine gas.

The crude mixture is subjected to washing, stripping and drying steps to obtain the halogenated isobutylene-isoprene rubber.

This step comprises washing the crude mixture with an alkaline solution and water and then stripping the washed crude mixture, thereby obtaining a mixture comprising halogenated isobutylene-isoprene rubber and water. In the stripping step, the second fluid medium is vaporized. The vaporized second fluid medium may be recovered. The recovered second fluid medium and impurities may be reused.

In an embodiment of the present invention, the washing may be performed with at least one alkali solution selected from the group consisting of sodium hydroxide and potassium hydroxide.

The drying step includes drying the mixture of halogenated isobutylene-isoprene rubber and water to obtain halogenated isobutylene-isoprene rubber.

The process for preparing halogenated isobutylene-isoprene rubber further comprises compressing the halogenated isobutylene-isoprene rubber into bales. The halogenated isobutylene-isoprene rubber obtained by the process of the present invention can be molded into various other forms.

The halogenated isobutylene-isoprene rubber obtained after the stripping and drying steps may be in the form of chips.

The process of the present invention for preparing halogenated isobutylene-isoprene rubber is an integrated process in which polymerization and halogenation are carried out without the need for isolation of isobutylene-isoprene rubber. In contrast, in conventional processes, isobutylene-isoprene rubber is isolated and then halogenated.

The conventional process performs two stripping operations, the first being after polymerization for the separation of isobutylene-isoprene rubber and the second being after halogenation for the separation of halogenated isobutylene-isoprene rubber. In contrast, the process of the present invention includes a stripping step only after halogenation to isolate the halogenated isobutylene-isoprene rubber.

It is estimated that the process of the present invention for preparing halogenated isobutylene-isoprene rubber can save 5% to 6% of the total project capital expenditure (CAPEX) and 20% to 25% of the total operating cost per year in terms of energy savings.

The key properties of the isobutylene-isoprene rubber produced by the process for preparing halogenated isobutylene-isoprene rubber of the present invention (e.g., related to the viscosity of the door,% halogenation,% volatiles) are the same as the quality of isobutylene-isoprene rubber produced by a process comprising separating the isobutylene-isoprene rubber by a stripping process.

Overall, the integration process of the present invention is simple. The process also consumes less steam and therefore produces less wastewater. The fluid medium requirements are also lower compared to conventional processes. Thus, the process of the present invention is simple, energy efficient, economical and environmentally friendly.

The invention is further described in view of the following experiments, which are for illustrative purposes only and are not to be construed as limiting the scope of the invention. The following laboratory scale experiments can be scaled up to industrial/commercial scale and the results extrapolated to industrial/commercial scale.