CN118459494A - A process for hydrolysis of organosilicon monomer - Google Patents

Abstract

The invention discloses an organosilicon monomer hydrolysis process, which belongs to the technical field of preparation of organic high molecular compounds, and comprises the steps of feeding organosilicon and water into a mixing module for mixing, wherein the molar ratio of the water to the organosilicon is 1:1.5-30, wherein the total flow range of the mixed materials is 20-800kg/h; carrying out hydrolysis reaction on the materials in the mixing module through a reaction module, wherein the reaction module is provided with at least two micro-channel reactors; the materials in the reaction module are sent into a continuous layering tower for layering; mixing the upper layer material in the continuous layering tower with 2-10% concentration sodium hydroxide water solution in the flow ratio of 2-8:1, feeding the materials subjected to alkaline washing in the micro-channel alkaline washing module into a continuous separation tower, and overflowing the crude organosilicon product of the materials into a rectification procedure from the upper layer of the continuous separation tower. The method is suitable for hydrolyzing various organic silicon, and can greatly reduce the occupied area of equipment under the same productivity and conversion rate compared with the hydrolysis process in the prior art.

Description

A process for hydrolysis of organosilicon monomer

Technical Field

The invention relates to the field of preparation of organic polymer compounds, in particular to a process for hydrolyzing an organosilicon monomer.

Background Art

The hydrolysis of organosilicon monomer refers to the process in which an organosilicon compound undergoes a hydrolysis reaction in water. It is widely used in chemical production. In the prior art, a tower continuous reaction process or a kettle process is often used to hydrolyze organosilicon. Its products are usually used to prepare specific silicon-based products, such as polysiloxanes, silicone oils and other products. Its products are widely used in the fields of coatings, sealants, adhesives, lubricants, silicone rubber, etc. In the process of realizing the embodiments of the present application, the inventors found that the tower continuous reaction process or kettle process in the prior art has the problems of large footprint, low output and low production efficiency.

The following is an analysis of the organosilicon hydrolysis process in the prior art, taking the equipment required for the hydrolysis of trimethylchlorosilane with an annual production capacity of 2,000 tons as an example;

The tower continuous reaction process requires a jacketed reaction tower in addition to conventional storage tanks. The inner diameter of the reaction tower is 20-35cm. With the jacket size, the outer diameter of the entire reaction tower is about 45-60cm, and the tower height is 10-25m. The required heat exchange medium and heat exchange energy consumption are both high, so in addition to the reaction tower, other auxiliary facilities also occupy a large area.

As for the kettle type, whether it is an intermittent kettle type or a series continuous kettle type, the volume requirement for the reactor is fixed. Taking 2,000 tons of production capacity as an example, assuming that the product density is 1, plus the water raw material water is assumed to be 1.5 times the amount of the product, the annual flux of the reactor reaction material is about 5,000 tons. With an annual production of 300 days, the daily flux is 25 tons. The volume utilization of the reactor is controlled at 70%. If a reactor completes the production capacity, the volume of the reactor needs to be 36 cubic meters (24,000L). Due to the exothermic characteristics of the reaction described in this patent, from the perspective of safe production, for industrial production, a single reactor should be controlled at about 5,000L. Even if other ancillary equipment is not considered, at least 5 reactors are required to meet the 2,000-ton production capacity requirement.

It can be seen that although the organosilicon hydrolysis process in the existing technology is relatively mature and its conversion rate can reach more than 99%, no matter which method is used in the existing technology, there will be problems such as large floor space, high energy consumption and low production efficiency.

Summary of the invention

In order to overcome the above-mentioned shortcomings of the prior art, increase the yield of the hydrolysis of the organosilicon monomer and reduce the floor space of the equipment, the present invention is achieved through the following technical solutions:

A process for hydrolyzing an organosilicon monomer comprises the following steps:

Material mixing: organic silicon and water are sent to a mixing module for mixing, the molar ratio of water to organic silicon is 1:1.5-30, the total flow rate of the mixed materials ranges from 20-800 kg/h, and the mixing module is a microchannel reactor;

Organic silicon hydrolysis: the material in the mixing module is subjected to a hydrolysis reaction through a reaction module, wherein the reaction module is a microchannel reactor, and the microchannel reactor is a heart-shaped microstructure module, and the material is a microchannel reactor made of silicon carbide or Hastelloy, and the number of the microchannel reactors is at least two;

Layering: The materials in the reaction module are fed into a continuous layering tower to layer the materials in the reaction module;

Alkali washing: the upper organic layer in the continuous layering tower and a sodium hydroxide aqueous solution with a concentration of 2-10% are sent to a microchannel alkali washing module, which is composed of a microchannel reactor, and the flow ratio of the sodium hydroxide aqueous solution to the upper organic layer is 1:2-8;

Separation: The alkali-washed material in the microchannel alkali-washing module is sent to a continuous separation tower, and the crude organosilicon product overflows from the upper layer of the continuous separation tower into the distillation process.

Furthermore, the organosilicon is an organosilicon monomer containing halogen, methoxy, phenyl, or ethoxy groups and capable of undergoing hydrolysis reaction. The inventors initially conducted research to explore the industrialization of hydrolysis of trimethylchlorosilane. After the process research of trimethylchlorosilane was successful, the inventors conducted experiments with straight-chain chlorosilanes with similar properties, as well as organosilicones using one of methoxy, phenyl, or ethoxy groups to replace the halogen elements in the straight-chain chlorosilanes, and also achieved success.

Furthermore, the organosilicon molecular structure contains straight-chain alkyl and chloro groups, that is, straight-chain chlorosilane-type organosilicon compounds, whose molecular structure contains straight-chain alkyl and chloro groups, as well as silicon atoms. Such compounds usually have the general formula RnSiCl _4-n , where R represents an alkyl group, n is 1 to 3, and straight-chain alkyl refers to a hydrocarbon group in which carbon atoms are arranged in a straight chain. In organic compounds, straight-chain alkyl groups are formed by a straight-line arrangement of carbon atoms, with a sufficient number of hydrogen atoms attached to each carbon atom so that the bonds between carbon atoms form a straight-line structure. The naming of straight-chain alkyl groups usually ends with "alkane", such as methyl (CH ₃ ), ethyl (C ₂ H ₅ ), propyl (C ₃ H ₇ ), etc.

Furthermore, the molecular structure of the organosilicon is an organosilicon in which the chlorine group of the linear chlorosilane is replaced by a group of methoxy, phenyl, or ethoxy, and the larger the group replacing the chlorine group of the linear chlorosilane, the higher the reaction temperature.

Furthermore, the total flow rate of the materials during the reaction is in the range of 20-800 kg/h, and the molar ratio of water to silicone is 1:1.5~30. This is an effective range obtained by the inventors after multiple experiments. Those skilled in the art can adjust within the above range according to the production requirements and the properties of the silicone itself.

Furthermore, the microchannel reactor is a heart-shaped microstructure module, and the material of the microchannel reactor is silicon carbide or Hastelloy. When studying how to reduce the footprint of the hydrolysis equipment, the inventor first improved the reaction module with the largest footprint. However, through multiple experimental analyses, it was confirmed that the microchannel reactor was used instead of the original reaction module for the experiment. However, it was found that the use of a microchannel reactor for organic silicon hydrolysis reaction would lead to poor reaction mass transfer effect, resulting in reduced reaction rate, incomplete reaction, easy to cause side reactions and increased by-product generation, and difficulty in controlling reaction conditions. Although the above situation has been improved through multiple parameter conditions, its effect still cannot enable it to be industrialized through a microchannel reactor. However, after further research by the inventor, it was found that if the alkali washing module is replaced with a microchannel reactor, and its process parameters are adjusted, and the microchannel reactor of the alkali washing module adopts a heart-shaped microstructure module, it can cooperate with other parameters and process steps of the present application to achieve the technical effect of the present application, so that it can fully meet the needs of industrialization.

Furthermore, the number of microchannel reactors in the reaction module is 2-20.

Preferably, the number of microchannel reactors of the linear chlorosilane organic silicon compound in the reaction module is 2-15.

Preferably, the organosilicon molecular structure is an organosilicon in which the chlorine group of the linear chlorosilane is replaced by a methoxy group or an ethoxy group, and the number of microchannel reactors in the reaction module is 5-20.

Preferably, the molecular structure of the organosilicon is an organosilicon in which the chlorine group of the linear chlorosilane is replaced by a phenyl group, and the number of microchannel reactors in the reaction module is 10-15.

Preferably, the liquid holding capacity of one microchannel reactor is 100 ml.

Furthermore, the residence time of the material in the reaction module is at least 4 seconds.

Preferably, the residence time of the linear chlorosilane organic silicon compound in the reaction module is 5-12 s.

Preferably, the organic silicon molecular structure is an organic silicon in which the chlorine group of the linear chlorosilane is replaced by a methoxy group or an ethoxy group, and its residence time in the reaction module is 8-20s.

Preferably, the organic silicon molecular structure is an organic silicon in which the chlorine group of the linear chlorosilane is replaced by a phenyl group, and its residence time in the reaction module is 15-30s.

Furthermore, the residence time of the material in the reaction module is 6-20s.

Furthermore, the microchannel alkali washing module is composed of a microchannel reactor, and the specifications of the microchannel reactor of the microchannel alkali washing module are consistent with those of the microchannel reactor of the reaction module.

Preferably, the number of the microchannel reactors is one half to one third of the microchannel reactors in the reaction module.

Furthermore, the reaction temperature range of the reaction module is 5-120° C., and the reaction pressure range is 0.1 MPa-1.5 MPa.

Preferably, the reaction temperature of the linear chlorosilane organic silicon compound in the reaction module is in the range of 10-30°C.

Preferably, the molecular structure of the organosilicon is an organosilicon in which the chlorine group of the linear chlorosilane is replaced by a methoxy group or an ethoxy group, and the reaction temperature range in the reaction module is 5-40°C.

Preferably, the molecular structure of the organosilicon is an organosilicon in which the chlorine group of the linear chlorosilane is replaced by a phenyl group, and the reaction temperature range in the reaction module is 60-120°C.

Furthermore, the reaction temperature range of the reaction module is 25-85°C.

Furthermore, the flow rate range of the organic silicon monomer is: 0.15-550kg/h.

Furthermore, the sodium hydroxide solution is a 3-7% sodium hydroxide aqueous solution.

Beneficial Effects

Taking the hydrolysis of trimethylchlorosilane as an example, we selected 10 reaction modules and 3 alkaline washing modules, and the total flux range can reach 300-600kg/h, of which about 55% of the product, that is, the product flux can reach 165-330kg/h, and the daily production capacity is 4-7.92 tons/day. According to the normal production of 300 days per year, the annual production capacity is 1200-2376 tons/year. The conventional high-throughput microchannel reactor module size is (15*30~30*50cm) and the reactor plus jacket accessories will not occupy more than 10 square meters.

From this we can see that:

The present application uses the small size and high surface area to volume ratio of the microchannel reactor to make the reaction materials and reaction conditions more uniform, thereby increasing the reaction rate. Compared with the traditional tower reactor, it is easier to accurately control the reaction conditions, including temperature, pressure, reaction material flow rate, etc. This precise controllability can improve the selectivity and yield of the reaction, so that it can achieve a faster reaction speed and save reaction time.

The modular design of the microchannel reactor in this application makes the system easier to expand and integrate, and can be used in combination with other processing units (such as separation units). The microchannel reactor can realize continuous flow reaction. Compared with batch reaction, this continuous flow method can achieve higher reaction efficiency and product purity. Continuous flow reaction can effectively control the parameters such as the feed rate, temperature and pressure of the reactants, thereby achieving higher process efficiency and overall production performance.

And because microchannel reactors are usually microscopic in size, this means that the heat and mass transfer inside the reactor is more uniform and efficient, that is, less energy is used to maintain the reaction temperature, which can reduce the possibility of local overheating, save energy consumption, and reduce the risk of explosion or accidental accidents. In addition, microchannel reactors can usually better control the mixing and separation of reactants, reduce unstable or unsafe operations, and produce less waste liquid and by-products. This helps reduce the burden of waste treatment and reduces production costs.

The process of this application can greatly reduce the floor space of the equipment while maintaining the conversion rate at the existing technical level. In terms of the floor space and size of the main reaction equipment of the same level of production capacity, the floor space of the equipment used in our method is only about 1/10 of that of other traditional processes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a process flow chart of the present application;

In the figure: 1. Mixing module, 2. Reaction module, 3. Continuous layering tower, 4. Microchannel alkaline washing module, 5. Continuous separation tower, A. Pump one, B. Pump two, C. Pump three, D. Pump four.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

DETAILED DESCRIPTION

Example 1: Taking trimethylchlorosilane as an example;

Material mixing: water and organosilicon (trimethylchlorosilane) are respectively sent to the mixing module 1 through pump 1 A and pump 2 B for mixing, wherein the mass flow rate of pump 1 A (water) is 97.2 kg/h, and the mass flow rate of pump 2 B (trimethylchlorosilane) is 388.8 kg/h. The mixing module 1 is a microchannel reactor;

Silicone hydrolysis: The material in the mixing module 1 is subjected to a hydrolysis reaction through the reaction module 2. The reaction module 2 is a microchannel reactor. The material of the microchannel reactor is silicon carbide and a heart-shaped microstructure module is selected. The number of the microchannel reactors is 7. The liquid holding capacity of the reaction module 2 is 700 ml. The temperature of the microchannel reactor is set at 15°C so that the microchannel reactor can react the mixed material through the microchannel reactor. The residence time of the mixed material in the reaction module 2 is 5.14S. At this point, the material outlet temperature is about 16°C.

Layering: The materials in the reaction module 2 are fed into the continuous layering tower 3 to layer the materials in the reaction module 2;

Alkali washing: The upper organic layer in the continuous layering tower 3 enters the microchannel alkali washing module 4 through pump 3C, with a flow rate of 297kg/h, and 5% sodium hydroxide solution is sent to the microchannel alkali washing module 4 through pump 4D, with a flow rate of 100kg/h. The microchannel alkali washing module 4 is a 2-piece silicon carbide module, and the material residence time is 1.4S.

Separation: The alkali-washed material in the microchannel alkali-washing module 4 is sent to the continuous separation tower 5, and the crude organosilicon overflows from the upper layer of the continuous separation tower 5 into the distillation, and the organosilicon conversion rate is 99.8%.

The reaction equation is as follows:

Example 2. This example is based on the scheme in Example 1, and the organosilicon monomer in Example 1 is replaced by dichlorodimethylsilane (DCDMS). The reaction parameters are as follows: reaction temperature: 20-50°C, number of microchannel modules: 5-20, monomer flow range: 0.15-550 kg/h, residence time: 5-15 s;

The reaction equation is as follows:

Hydrolysis reaction: DCDMS reacts with water to generate dimethyldihydroxysilane (DMDMS) and hydrogen chloride (HCl).

DCDMS+4H ₂ O→(CH ₃ ) ₂ Si(OH) ₂ +2HCl

Condensation reaction: Through the condensation reaction, dimethyldihydroxysilane is polymerized into methylsiloxane chains to produce methyl silicone oil.

(CH ₃ ) ₂ Si(OH) ₂ →(CH ₃ ) ₃ SiO(CH ₃ ) ₂ Si(OH)

(CH ₃ ) ₃ SiO(CH ₃ ) ₂ Si(OH)→(CH ₃ ) ₃ SiO(CH ₃ ) ₂ SiO(CH ₃ ) ₃ SiO….

Example 3: This example is based on the solution in Example 1, and the organosilicon monomer in Example 1 is replaced by ethylene dimethyl organosilicon monomer, and its structural formula is:

Wherein R, R1 = Cl, and the reaction parameters are as follows: reaction temperature: 20-60°C, number of microchannel modules: 5-20, monomer flow range: 0.15-550 kg/h, residence time: 4-15 s.

Example 4: This example is based on the solution in Example 1, and the organosilicon monomer in Example 1 is replaced by a methylethyl organosilicon monomer, and the structural formula is:

Wherein R, R1 = Cl, and the reaction parameters are as follows: reaction temperature: 10-40°C, number of microchannel modules: 5-20, monomer flow range: 0.15-550 kg/h, residence time: 8-20 s.

Example 5. This example is based on the scheme in Example 1, and the organosilicon monomer in Example 1 is replaced by a hydrogenated ethyl organosilicon monomer, and the structural formula is:

Wherein R, R1 = Cl, and the reaction parameters are as follows: reaction temperature: 10-40°C, number of microchannel modules: 5-20, monomer flow range: 0.15-550 kg/h, residence time: 8-20 s.

Example 6: This example is based on the scheme in Example 1, and the organosilicon monomer in Example 1 is replaced by a hydrogen-containing methyl organosilicon monomer, and the structural formula is:

Wherein R, R1 = Cl, and the reaction parameters are as follows: reaction temperature: 10-40°C, number of microchannel modules: 5-20, monomer flow range: 0.15-550 kg/h, residence time: 8-20 s.

Example 7. This example is based on the scheme in Example 1, and the organosilicon monomer in Example 1 is replaced by a hydrogenated vinyl organosilicon monomer, and the structural formula is:

Wherein R, R1 = Cl, and the reaction parameters are as follows: reaction temperature: 10-40°C, number of microchannel modules: 5-20, monomer flow range: 0.15-550 kg/h, residence time: 8-20 s.

Example 8: This example is based on the scheme in Example 1, and the organosilicon monomer in Example 1 is replaced by a hydrogen-containing phenyl organosilicon monomer, and the structural formula is:

Wherein R, R1 = Cl, and the reaction parameters are as follows: reaction temperature: 60-120°C, number of microchannel modules: 10-15, monomer flow range: 0.15-550 kg/h, residence time (s): 15-30.

Example 9. This example is based on the scheme in Example 1, and the organosilicon monomer in Example 1 is replaced by a hydrogen-containing benzyl organosilicon monomer, and the structural formula is:

Wherein R, R1 = Cl, and the reaction parameters are as follows: reaction temperature: 60-120°C, number of microchannel modules: 10-15, monomer flow range: 0.15-550 kg/h, residence time: 15-30 s.

The conversion rates in the above embodiments can reach more than 99%.

The specific benefits are as follows: taking the hydrolysis of trimethylchlorosilane as an example, we select 10 reaction modules, 2 alkaline washing modules, and 2 water washing modules. The total flux range can reach 300-600kg/h, of which about 55% of the products, that is, the product flux can reach 165-330kg/h, and the daily production capacity is 4-7.92 tons/day. According to the normal production of 300 days per year, the annual production capacity is 1200-2376 tons/year. The conventional high-throughput microchannel reactor module size is (15*30~30*50cm) reactor plus jacket accessory facilities, and the land area will not exceed 10 square meters. It can be seen that the process of this application can increase the yield of its organic silicon monomer hydrolysis while reducing the floor area of its equipment, so that in terms of the floor area and size of the main reaction equipment of the same level of production capacity, our method may be less than 1/10 of other traditional processes, that is, the same production space using the production capacity of this application can be about 10 times higher than the capacity of the prior art.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1. The organic silicon monomer hydrolysis process is characterized by comprising the following steps of:

Mixing materials: feeding the organic silicon and water into a mixing module for mixing, wherein the molar ratio of the water to the organic silicon is 1:1.5-30, wherein the total flow range of the mixed materials is 20-800kg/h, and the mixing module is a micro-channel reactor;

Organosilicon hydrolysis: carrying out hydrolysis reaction on materials in the mixing module through a reaction module, wherein the reaction module is a micro-channel reactor, the micro-channel reactor is a heart-shaped micro-structure module, the materials are silicon carbide or hastelloy micro-channel reactors, and the number of the micro-channel reactors is at least two;

Layering: feeding the materials in the reaction module into a continuous layering tower, and layering the materials in the reaction module;

Alkali washing: the method comprises the steps of feeding an upper organic layer and a sodium hydroxide aqueous solution with the concentration of 2-10% in a continuous layering tower into a micro-channel alkaline washing module, wherein the micro-channel alkaline washing module consists of a micro-channel reactor, and the flow ratio of the sodium hydroxide aqueous solution to the upper organic layer is 1:2-8;

Separating: and (3) conveying the alkaline washed materials in the micro-channel alkaline washing module into a continuous separation tower, and overflowing the crude organosilicon products of the alkaline washed materials from the upper layer of the continuous separation tower into a rectification process.

2. A process for the hydrolysis of a silicone monomer according to claim 1, wherein the silicone is a hydrolysis-producing silicone monomer containing one of halogen, methoxy, phenyl, ethoxy.

3. A process for the hydrolysis of silicone monomers as recited in claim 2, wherein said silicone molecular structure comprises linear alkyl groups and chloro groups.

4. A silicone monomer hydrolysis process according to any one of claims 1-3, wherein the number of microchannel reactors in the reaction module is 2-20.

5. A process for the hydrolysis of silicone monomers as recited in claim 1, wherein said material has a residence time in said reaction module of at least 4s.

6. A process for the hydrolysis of silicone monomers as set forth in claim 5 wherein said material has a residence time in the reaction module of from 8 to 20 seconds.

7. The process of claim 1, wherein the mixing module is a microchannel reactor, and the number of microchannel reactors in the microchannel caustic wash module is one half to one third of the number of microchannel reactors in the reaction module.

8. A process for the hydrolysis of silicone monomers as set forth in claim 1, wherein said reaction module has a reaction temperature in the range of: 5-120 ℃, and the reaction pressure ranges from: 0.1Mpa-1.5Mpa.

9. The process for hydrolyzing an organosilicon monomer according to claim 8, wherein the flow rate of the organosilicon monomer ranges from: 0.15-550kg/h.

10. A process for the hydrolysis of organosilicon monomers as set forth in claim 1, characterized in that said sodium hydroxide solution is 3-7% aqueous sodium hydroxide solution.