Method for removing organic chlorine and inorganic chlorine in organic silicon hydrolysate
By using reduced iron powder in the reactor for dechlorination reaction with hydrolysate, the problem of removing organic chlorine and inorganic chlorine in the silicone hydrolysate was successfully solved, efficient removal and product quality improvement were achieved, and equipment corrosion and cost increase were avoided.
Patent Information
- Application Number
- CN202411703612.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-02-28
AI Technical Summary
The prior art is difficult to effectively remove organic and inorganic chlorine present in silicone hydrolysates, resulting in a shift in viscosity of the hydrolysate, which is not conducive to storage and transportation, and the presence of organic and inorganic chlorine can corrode the equipment.
The reduced iron powder and the hydrolysate were used to dechlorinate in the reactor, and the organic and inorganic chlorine in the hydrolysate was removed by nitrogen replacement, heating and stirring and natural pressure-raising steps, and the refined oil phase was obtained by standing separation, filtration and water washing.
The efficient removal of organic and inorganic chlorine in silicone hydrolysate is achieved, the product quality of the hydrolysate is improved, the equipment corrosion is avoided, and the cost of subsequent processing steps is reduced.
Abstract
Description
Technical field:
[0001] The patent of this invention belongs to the technical field of purification of organosilicon dimethylsiloxane hydrolyzate, and specifically relates to a method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate. Background technology:
[0002] The hydrolyzate is a cyclic polysiloxane (Me2SiO) obtained by hydrolysis of dimethyldichlorosilane monomer. n (referred to as cyclic) and linear polysiloxane [HO(Me2SiO) n H] (referred to as silane), the preparation process of which is as follows: silicon powder and methyl chloride gas react in a fluidized bed reactor in the presence of a copper catalyst to produce a methylchlorosilane mixed monomer, the mixed methylchlorosilane monomer is separated by distillation to obtain dimethyldichlorosilane and other various refined monomers; dimethyldichlorosilane reacts with water or concentrated hydrochloric acid to generate a hydrolyzate and concentrated hydrochloric acid or HCl gas.
[0003] Since 100% purity cannot be reached in dimethyldichlorosilane, trace trimethylchlorosilane and methyltrichlorosilane will be brought into dimethyldichlorosilane, and more trace saturated alkanes are mainly olefins and chloroalkanes. After the hydrolysis of the above-mentioned dimethyldichlorosilane, HCl, chloroalkanes (including raw materials brought in and generated by reaction, which is a kind of structural chlorine), saturated alkanes, olefins, and Si-Cl (hereinafter referred to as Si structural chlorine) without complete reaction are present in the hydrolyzate. Si structural chlorine is easier to be removed by further hydrolysis, but chloroalkanes are difficult to be removed by simple washing and alkali washing, and chloroalkanes are not stable in the product, even at normal temperatures, they will gradually decompose and release HCl, and the temperature rise will accelerate the reaction, causing the hydrolyzate to be acidic (i.e., acid reversal), and the olefins and alcohols generated by the reaction will also have an impact on the product quality.
[0004] Therefore, the presence of organic chlorine and inorganic chlorine in the hydrolyzate can cause the hydrolyzate viscosity to shift, which is unfavorable for the storage and transportation of the hydrolyzate, affects the direct or reprocessed product application of the hydrolyzate, and the presence of organic chlorine and inorganic chlorine seriously corrodes the equipment. At present, the conventional dechlorination method is to wash the hydrolyzate with multi-stage water and then carry out liquid alkali washing. The shortcoming of this method is that only the HCl and Si-Cl structural chlorine in the hydrolyzate can be removed, and the chlorine removal efficiency in the chloroalkane is very low. Liquid alkali washing can also cause a small amount of sodium silicate to enter the hydrolyzate product because the hydrolyzate is not allowed to stand for a long time, and inorganic salts increase in the hydrolyzate product, which finally affects the quality of the hydrolyzate product. Summary of the invention:
[0005] The purpose of the present invention is to provide a method for removing organic chlorine and inorganic chlorine from organosilicon hydrolysate; the method of the present invention is simple, has mild reaction conditions and is easy to operate.
[0006] The technical solution of the present invention discloses a method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate, which comprises the following steps:
[0007] (1) Dechlorination reaction: Reduced iron powder and hydrolyzate are mixed and placed in a reactor. After nitrogen displacement at normal pressure, the reactor is sealed and heated and stirred for 0.5-2.5 hours, and the pressure is naturally increased;
[0008] The basic reaction equation is as follows:
[0009] 2HCL+Fe→FeCl2+H2↑
[0010] Fe+2RCl+H2→FeCl2+2RH(saturated alkane)
[0011] The reduced iron powder acts as a reducing agent to undergo oxidation reaction and loses electrons, while the chlorinated alkane gains electrons, converting the chlorine in the chlorinated alkane and chlorinated olefin into Cl - The chloroalkanes react to form saturated alkanes.
[0012] (2) Standing separation: Stop stirring, cool naturally to 85-95°C, and stand for separation for 10 min-1 h. Then, release the pressure in the reactor to normal pressure, pour the reaction materials into a separatory funnel, discharge the water phase, and obtain the oil phase.
[0013] (3) Oil phase filtration: filtering the oil phase in step (2) to remove solids and suspended matter in the oil phase;
[0014] (4) Washing the oil phase with water: Add deionized water to the oil phase filtered in step (3) and keep the temperature at 85-95°C. Wash with water 2-3 times to finally obtain a refined oil phase.
[0015] Furthermore, the reduced iron powder in step (1) is 40-500 mesh.
[0016] Furthermore, in step (1), the mass ratio of reduced iron powder to hydrolyzate is 0.01-0.1:1.
[0017] Furthermore, deionized water is added in step (1), and the mass ratio of deionized water to hydrolyzate is 0.1-1:1.
[0018] Furthermore, in step (1), the reaction temperature in the reactor is 110-130°C.
[0019] Furthermore, in step (1), the reactor is closed and naturally pressurized during the heating process, and the reaction pressure is 0.1-0.2 MPaG.
[0020] Furthermore, the stirring speed in step (1) is 100-400 r / min.
[0021] Advantages of the present invention:
[0022] 1. The present invention discloses a method for removing organic chlorine and inorganic chlorine from organosilicon hydrolysate, which is simple and easy to operate. Reduced iron powder, deionized water and hydrolysate are mixed, and the organic chlorine and inorganic chlorine in the hydrolysate are removed by reaction in a reactor, thereby achieving the removal of organic chlorine and inorganic chlorine in the hydrolysate and avoiding adding new salt impurities to the organosilicon hydrolysate, thereby effectively improving the quality of 107 silicone rubber.
[0023] 2. The quality of hydrolyzate products has been improved. Hydrolyzate can be directly used as raw material for the production of 107 silicone rubber, avoiding the consumption of a large amount of alkaline catalyst by residual chlorine when DMC synthesizes 107 silicone rubber, thus reducing costs. It can also be used as vacuum cracking raw material to produce dimethylcyclosiloxane. Removing organic and inorganic chlorine from hydrolyzate can also avoid corrosion of the next production equipment. Specific implementation method:
[0024] The present invention is further described in detail below by way of examples.
[0025] Embodiment 1: A method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate, comprising the following steps:
[0026] (1) Dechlorination reaction: 6 g of reduced iron powder, 100 g of deionized water and 200 g of hydrolyzate were mixed and placed in a reactor. After nitrogen displacement at normal pressure, the reactor was sealed and heated to 120° C. and stirred for 2 h. The reaction pressure in the reactor was 0.18 MPaG and the stirring speed was 300 r / min.
[0027] (2) Standing and stratifying: Stop stirring, cool naturally to 85°C, stand and separate for 10 min-1 h, then release the pressure in the reactor to normal pressure, pour the reaction materials into a separatory funnel, discharge the water phase to obtain the oil phase, and separate the Cl in the water phase. - The content was tested and Cl - The content is 205.42ppm.
[0028] (3) Oil phase filtration: Filter the oil phase in step (2) to remove unreacted reduced iron powder solids and suspended matter in the oil phase.
[0029] (4) Washing the oil phase with water: Add deionized water to the oil phase filtered in step (3) at a temperature of 85-95°C, and repeat the washing twice to obtain a refined oil phase.
[0030] Example 2: A method for removing organic chlorine and inorganic chlorine from organosilicon hydrolysate, comprising the following steps:
[0031] (1) Dechlorination reaction: 10 g of reduced iron powder, 100 g of deionized water and 200 g of hydrolyzate were mixed and placed in a reactor. After nitrogen displacement at normal pressure, the reactor was sealed and heated to 110° C. and stirred for 2.5 h. The reaction pressure in the reactor was 0.2 MPaG and the stirring speed was 200 r / min.
[0032] (2) Standing and stratifying: Stop stirring, cool naturally to 90°C, stand and separate for 10 min-1 h, then release the pressure in the reactor to normal pressure, pour the reaction materials into a separatory funnel, discharge the water phase to obtain the oil phase, and separate the Cl in the water phase. - The content was tested and Cl - The content is 212.42ppm.
[0033] (3) Oil phase filtration: Filter the oil phase in step (2) to remove unreacted reduced iron powder solids and suspended matter in the oil phase.
[0034] (4) Washing the oil phase with water: Add deionized water to the oil phase in step (3) at a temperature of 85-95°C and repeat the washing three times to obtain a refined oil phase.
[0035] Example 3: A method for removing organic chlorine and inorganic chlorine from organosilicon hydrolysate, comprising the following steps:
[0036] (1) Dechlorination reaction: 20 g of reduced iron powder, 100 g of deionized water and 200 g of hydrolyzate were mixed and placed in a reactor. After nitrogen displacement at normal pressure, the reactor was sealed and heated to 130° C. and stirred for 1.5 h. The reaction pressure in the reactor was 0.15 MPaG and the stirring speed was 400 r / min.
[0037] (2) Standing and stratifying: Stop stirring, cool naturally to 95°C, stand and separate for 10 min-1 h, then release the pressure in the reactor to normal pressure, pour the reaction materials into a separatory funnel, discharge the water phase to obtain the oil phase, and separate the Cl in the water phase. - The content was tested and Cl - The content is 213.14ppm.
[0038] (3) Filtration: Filter the oil phase in step (2) to remove unreacted reduced iron powder solids and suspended matter in the oil phase.
[0039] (4) Washing the oil phase with water: Add deionized water to the oil phase in step (3) at a temperature of 85-95°C and repeat the washing twice to obtain a refined oil phase.
[0040] Comparative Example 1: Prior Art: (1) 100 g of 5% sodium hydroxide solution and 200 g of Cl -The hydrolyzate with a content of 18.89 ppm was placed in a reactor at a temperature of 120°C, a rotation speed of 190 r / min, and a reaction time of 2 h; (2) the stirring was stopped, the temperature was naturally lowered to 90°C, the reaction material was poured into a separatory funnel, the water phase was discharged, and the oil phase was obtained. The Cl in the water phase was - The content was tested and Cl - The content is 93.82 ppm; (3) The oil phase is washed twice with deionized water and drained to obtain the oil phase.
[0041] It is obvious that the Cl contained in the aqueous phase after separation in Example 3 of the present invention - The content is the highest, and the Cl contained in the aqueous phase after separation in Comparative Example 1 - The content is the lowest, and it is obvious that the method disclosed in the present invention has the best removal effect on organic chlorine and inorganic chlorine in silicone hydrolyzate.
[0042] Experiment 1: The same amount of the oil phase after removing organic chlorine and inorganic chlorine from Examples 1-3 and Comparative Example 1 was used to prepare 107 silicone rubber, wherein the amount of alkaline catalyst required to produce 107 silicone rubber from the oil phase after removing organic chlorine and inorganic chlorine from Example 1 was 25ppm, and the turbidity was 8NTU; the amount of alkaline catalyst required to produce 107 silicone rubber from the oil phase after removing organic chlorine and inorganic chlorine from Example 2 was 22ppm, and the turbidity was 8NTU; the amount of alkaline catalyst required to produce 107 silicone rubber from the oil phase after removing organic chlorine and inorganic chlorine from Example 3 was 22ppm, and the turbidity was 8NTU. The amount of alkaline catalyst to be consumed is 20ppm, and the turbidity is 6NTU; the amount of alkaline catalyst required to produce 107 silicone rubber using the oil phase after removing organic chlorine and inorganic chlorine in Comparative Example 3 is 32ppm, and the turbidity is 11NTU; it is obvious that the method of the present invention can effectively remove organic chlorine and inorganic chlorine in the hydrolyzate, avoid adding new salt impurities to the hydrolyzate, reduce the turbidity of 107 silicone rubber, and effectively improve the quality of 107 silicone rubber; at the same time, the consumption of the alkaline catalyst is reduced, and the rate of synthesizing 107 silicone rubber is increased.
[0043] The above are preferred embodiments of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A method for removing organic chlorine and inorganic chlorine from organosilicon hydrolysate, characterized in that: It includes the following steps: (1) Dechlorination reaction: Reduced iron powder and hydrolyzate are mixed and placed in a reactor. After nitrogen displacement at normal pressure, the reactor is sealed and heated and stirred for 0.5-2.5 hours, and the pressure is naturally increased; (2) Standing separation: stop stirring, cool naturally to 85-95°C, stand for separation for 10 min-1 h, then release the pressure in the reactor to normal pressure, pour the reaction materials into a separatory funnel, discharge the water phase, and obtain the oil phase; (3) Oil phase filtration: filtering the oil phase in step (2) to remove solids and suspended matter in the oil phase; (4) Washing the oil phase with water: Add deionized water to the oil phase filtered in step (3) at a temperature of 85-95° C. and wash it 2-3 times to finally obtain a refined oil phase.
2. The method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate according to claim 1, characterized in that: The reduced iron powder in step (1) is 40-500 mesh.
3. The method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate according to claim 1, characterized in that: In step (1), the mass ratio of reduced iron powder to hydrolyzate is 0.01-0.1:
1.
4. The method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate according to claim 1, characterized in that: Deionized water is also added in step (1), and the mass ratio of deionized water to hydrolyzate is 0.1-1:
1.
5. The method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate according to claim 1, characterized in that: In step (1), the reaction temperature in the reactor is 110-130°C.
6. The method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate according to claim 1, characterized in that: In step (1), the reactor is closed and naturally pressurized during the heating process, and the reaction pressure is 0.1-0.2 MPaG.
7. The method for removing organic chlorine and inorganic chlorine from organosilicon hydrolyzate according to claim 1, characterized in that: The stirring speed in step (1) is 100-400 r / min.