A process system and method for hydrolysis of dimethyldichlorosilane

Abstract

The application relates to the field of chemical engineering technology, and discloses a process system and method for hydrolysis of dimethyldichlorosilane, which comprises washing degassing, two-stage hydrolysis and phase separation, and two-stage countercurrent water washing. A new type of supergravity equipment is adopted, on one hand, small equipment volume and high-efficiency reaction separation greatly save the investment cost; on the other hand, concentrated acid and dilute acid are separately introduced into a reactor, and a pre-reaction of the dilute acid and raw material dimethyldichlorosilane effectively improves the ring proportion of the product, reduces the product viscosity, and makes the product more competitive.

Description

Technical Field

[0001] The present invention relates to the field of chemical technology and chemical engineering technology, and in particular to a process system and method for hydrolyzing dimethyldichlorosilane. Background Art

[0002] Dimethyldichlorosilane is the most widely produced monomer in the silicone industry. The linear or cyclic oligomeric dimethylsiloxanes produced by its hydrolysis are essential intermediates for the preparation of downstream products such as coatings and functional materials. Dimethyldichlorosilane hydrolysis processes are primarily divided into azeotropic acid hydrolysis and saturated acid hydrolysis. The azeotropic acid hydrolysis process involves excess water, using an unsaturated azeotropic acid to react. The hydrochloric acid concentration is brought to saturation through the hydrolysis of dimethyldichlorosilane, and then vaporized hydrogen chloride is obtained through distillation. Advantages include a simple process, easy operation, and a high proportion of cyclic compounds. However, since the resulting hydrogen chloride releases a large amount of heat when dissolved in water, this process consumes a lot of energy to maintain a stable reaction temperature between 20 and 40°C. Furthermore, the small molecular weight hydrolyzates in the recovered vaporized hydrochloric acid are difficult to remove, which can easily clog pipelines and equipment. The saturated acid hydrolysis process is an aqua-depleted hydrolysis process. It uses saturated hydrochloric acid at a concentration greater than 37% to hydrolyze dimethyldichlorosilane. The reaction directly produces gaseous hydrogen chloride, which, after cooling and washing, is often used to synthesize chloromethane. Compared with the azeotropic acid hydrolysis process, this process is simpler, reduces energy consumption and losses, and produces less wastewater. However, the lack of water during the saturated acid hydrolysis process results in incomplete hydrolysis, which can easily lead to an increase in the amount of chlorine-capped linear bodies, a higher proportion of linear bodies in the product, and slightly higher product viscosity. Currently, the dimethyl hydrolysis units of domestic methylchlorosilane manufacturers have largely completed the transition from azeotropic acid hydrolysis to saturated acid hydrolysis.

[0003] Dimethyldichlorosilane undergoes hydrolysis and condensation reaction to generate polydimethylsiloxane and hydrogen chloride. The specific process is as follows:

[0004]

[0005] In actual production, due to the difference in water consumption in different processes, dimethyl hydrolysis has different reaction pathways. Its hydrolysis reaction formula under excess water conditions is as follows:

[0006]

[0007] The hydrolysis reaction under water-deficient conditions is as follows:

[0008]

[0009] Indicators for measuring the quality of hydrolyzate products include acid value, kinematic viscosity, molecular weight, chloride ion content, and appearance. Molecular weight and kinematic viscosity are significantly affected by the reaction loop temperature and acid concentration; while the control of chloride ion content, acid value, and appearance is primarily determined by the post-processing loop. In actual production, to improve product quality, multi-stage hydrolysis and water washing devices are often used. For example, the dimethyldichlorosilane hydrolyzate dechlorination method described in patent CN114682197A includes a four-stage washing unit to ensure thorough reaction while reducing the presence of free chlorine in the system. However, as the number of stages in the process increases, the condensation reaction also proceeds, increasing the viscosity of the hydrolyzate, which will affect the mass transfer efficiency of subsequent processing steps and cause problems such as water sedimentation difficulties. How to balance these two aspects (controllable viscosity of the hydrolyzate and low chlorine content in the hydrolyzate) and overcome the problem of oil-containing hydrogen chloride recovery are the main technical difficulties of the current dimethyl hydrolysis process. Summary of the Invention

[0010] (1) Technical problems solved

[0011] In view of the deficiencies in the prior art, the present invention provides a process system and method for hydrolyzing dimethyldichlorosilane, which has the advantages of reduced product viscosity and chloride ion content, improved purity of recovered hydrogen chloride, short reaction time and low cost.

[0012] (2) Technical solution

[0013] A process system for hydrolyzing dimethyldichlorosilane, comprising:

[0014] Concentrated acid feed pump (1), dimethyldichlorosilane feed pump (2), desalted water feed pump (3), novel two-stage reaction separation coupled supergravity equipment (4), connecting pipe (7), fine phase tank (8), concentrated acid circulation pump (9), washing tower (10), first crude hydrolyzate delivery pump (11), supergravity hydrolysis reaction phase separator (12), dilute acid cooler (15), first dilute acid circulation pump (16), second crude hydrolyzate delivery pump (17), water washing rotary disk tower (18), second dilute acid circulation pump (19), third crude hydrolyzate delivery pump (20), supergravity water washing reaction phase separator (21), third dilute acid circulation pump (24);

[0015] In order to meet the phase separation requirements, the novel two-stage reaction separation coupling supergravity device (4) is provided with an inner cylinder wall (5) and an outer cylinder wall (6) in the lower middle part of the device, and three-phase coarse phase separation is completed between the inner and outer cylinder walls;

[0016] The high gravity hydrolysis reaction phase separator (12) is provided with an inner cylinder wall (13) and an outer cylinder wall (14) to meet the phase separation requirements, and two-phase phase separation is completed between the inner and outer cylinder walls;

[0017] The ultra-gravity water washing reaction phase separator (21) is provided with an inner cylinder wall (22) and an outer cylinder wall (23) to meet the phase separation requirements, and two-phase phase separation is completed between the inner and outer cylinder walls;

[0018] The system connection sequence is:

[0019] A novel two-stage reaction separation coupled supergravity equipment, wherein the first liquid inlet at the top is connected to the concentrated acid inlet and the coarse and fine phase heavy phase liquid outlets respectively through a concentrated acid feed pump and a concentrated acid circulation pump, the second liquid inlet at the top is connected to the liquid outlet of the scrubber, the gas outlet is connected to the gas inlet of the scrubber, the middle liquid inlet is connected to the dimethyldichlorosilane inlet through a dimethyldichlorosilane feed pump, and is connected to the heavy phase liquid outlet of the supergravity hydrolysis reaction phase separator through a dilute acid cooler and a first dilute acid circulation pump, the middle light phase liquid outlet is connected to the fine phase tank through a connecting pipe, and the bottom heavy phase liquid outlet is connected to the first liquid inlet at the top and the liquid inlet of the scrubber through a concentrated acid circulation pump;

[0020] The washing tower has a liquid inlet connected to the concentrated acid inlet and the coarse and fine phase heavy phase liquid outlets through a concentrated acid feed pump and a concentrated acid circulation pump, respectively; its liquid outlet is connected to the second liquid inlet at the top of the novel two-stage reaction separation coupling supergravity equipment; its gas inlet is connected to the coarse and fine phase gas outlets; and its gas outlet is the hydrogen chloride gas outlet;

[0021] A fine phase separation tank, whose material inlet is connected to the light phase liquid outlet in the middle of the novel two-stage reaction separation coupling high gravity equipment through a connecting pipe, whose gas outlet is connected to the gas inlet of the washing tower, whose light phase liquid outlet is connected to the liquid inlet of the high gravity hydrolysis reaction phase separator through a first crude hydrolyzate delivery pump, and whose heavy phase liquid outlet is connected to the first liquid inlet at the top of the novel two-stage reaction separation coupling high gravity equipment and the liquid inlet of the washing tower through a concentrated acid circulation pump;

[0022] The liquid inlet of the high-gravity hydrolysis reaction phase separator is connected to the light phase liquid outlet of the fine phase separation tank and the heavy phase liquid outlet of the water washing turntable tower respectively through the first crude hydrolyzate delivery pump and the second dilute acid circulation pump. The light phase liquid outlet is connected to the light phase liquid inlet of the water washing turntable tower through the second crude hydrolyzate delivery pump, and the heavy phase liquid outlet is connected to the liquid inlet of the middle part of the novel two-stage reaction separation coupling high-gravity equipment through the dilute acid cooler and the first dilute acid circulation pump.

[0023] a water washing turntable tower, wherein the light phase liquid inlet is connected to the light phase liquid outlet of the supergravity hydrolysis reaction phase separator via a second crude hydrolyzate delivery pump, the heavy phase liquid inlet is connected to the heavy phase liquid outlet of the supergravity water washing reaction phase separator via a third dilute acid circulation pump, the light phase liquid outlet is connected to the liquid inlet of the supergravity water washing reaction phase separator via the third crude hydrolyzate delivery pump, and the heavy phase liquid outlet is connected to the liquid inlet of the supergravity hydrolysis reaction phase separator via a second dilute acid circulation pump;

[0024] The liquid inlet of the ultra-gravity water washing reaction phase separator is connected to the desalted water inlet and the light phase liquid outlet of the water washing turntable tower through the desalted water feed pump and the third crude hydrolyzate delivery pump respectively. The light phase liquid outlet is the hydrolyzate outlet, and the heavy phase liquid outlet is connected to the heavy phase liquid inlet of the water washing turntable tower through the third dilute acid circulation pump.

[0025] A production method for hydrolyzing dimethyldichlorosilane comprises the following steps:

[0026] (1) The concentrated acid of the fresh feed for washing and degassing is mixed with the concentrated acid obtained from the first-stage hydrolysis phase separation and introduced into the top of the washing tower. In the tower, the mixed acid is countercurrently and partially cross-currently contacted with the impure hydrogen chloride gas from the coarse and fine phases of the first-stage hydrolysis to complete the washing and degassing work; the hydrogen chloride gas from which the impurity small molecular siloxane oil substances are removed passes through the demister and leaves the washing tower from the gas outlet at the top of the tower. The concentrated acid is extracted from the bottom of the tower and sent to the outer ring packing of the new double-stage reaction separation coupled supergravity equipment for the second stage of concentrated acid hydrolysis reaction;

[0027] (2) The first stage supergravity double-stage hydrolysis reaction phase separation freshly fed dimethyldichlorosilane and the dilute acid obtained from the second stage hydrolysis phase separation are mixed and fed into the new double-stage reaction separation coupled supergravity equipment. The two-phase material entering through the central jet is quickly broken and renewed on the surface of the oil-water two phases under the high-speed shear of the inner ring rotating filling rotor, and the dimethyldichlorosilane and the dilute acid are quickly and fully mixed to carry out the first stage dilute acid hydrolysis reaction; the freshly fed concentrated acid and the concentrated acid obtained from the coarse and fine phases of the first stage hydrolysis are mixed and fed into the new double-stage reaction separation coupled supergravity equipment. The material enters the annular gap and is jetted toward the outer ring rotating filling rotor, and is quickly and fully mixed with the material that has completed the first stage dilute acid hydrolysis reaction to carry out the second stage The concentrated acid hydrolysis reaction is carried out in the first stage; subsequently, the mixed liquid that has completed the two-stage reaction through the packing layer carries the hydrogen chloride gas generated by the reaction and is thrown onto the funnel-shaped inner wall under the action of centrifugal force. The swirling liquid flows downward, and the impure hydrogen chloride gas is discharged from the gas outlet set on the side of the outer cylinder wall through the gap between the inner and outer cylinders, thereby achieving gas-liquid separation; at the bottom of the equipment shell, the oil and water phases are roughly separated, and the crude oil phase flows into the fine phase tank through the connecting pipe for fine phase separation. The concentrated acid of the aqueous phase is extracted from the bottom and mixed with the concentrated acid from the fine phase tank and sent to the washing tower and the outer ring packing of the new double-stage reaction separation coupling high-gravity equipment; the light phase first crude hydrolyzate obtained by phase separation in the fine phase tank is sent to the high-gravity hydrolysis reaction phase separator for second-stage hydrolysis and phase separation;

[0028] (3) Second-stage supergravity hydrolysis reaction phase separation The light phase first crude hydrolyzate obtained by the above phase separation is mixed with the dilute acid from the first-stage water washing and fed into the supergravity hydrolysis reaction phase separator. The two-phase materials entering through the central jet are quickly and fully mixed, and a dilute acid hydrolysis reaction is carried out to generate hydrogen chloride dissolved in the liquid phase. No gas escapes during the process. The mixed liquid that completes the hydrolysis reaction through the packing layer is thrown onto the funnel-shaped inner wall under the action of centrifugal force, and the swirling liquid flows downward, and the oil and water phases are quickly separated. At the bottom of the rotating filling rotor shell, the oil and water phases are separated, wherein the second crude hydrolyzate is discharged as the light component of the oil phase at the light phase liquid outlet on the side of the outer cylinder wall, and the dilute acid is discharged as the heavy component of the water phase at the heavy phase liquid outlet at the bottom.

[0029] (4) Phase separation of the first-stage rotary disc tower water washing reaction: The light phase second crude hydrolyzate obtained by the above phase separation and the dilute acid from the second-stage water washing are respectively introduced into the bottom and top of the water washing rotary disc tower as the light and heavy phases, and are contacted with each other in countercurrent in the tower for water washing and separation. Under the agitation of the fixed rotary disc, the dispersed phase forms small droplets, which increases the mass transfer area. After the process is completed, the light phase third crude hydrolyzate and the heavy phase dilute acid are discharged from the liquid outlets at the top and bottom of the tower, respectively;

[0030] (5) Second-stage supergravity water washing reaction phase separation The light phase third crude hydrolyzate obtained by the above phase separation is mixed with the fresh desalted water and fed into the supergravity water washing reaction phase separator, wherein the reaction and separation process are similar to those in the supergravity hydrolysis reaction phase separator. The hydrolyzate is discharged as the light component of the oil phase at the light phase liquid outlet on the side of the outer cylinder wall, and the dilute acid is discharged as the heavy component of the water phase at the heavy phase liquid outlet at the bottom. However, the pH value in the supergravity water washing reaction phase separator is significantly different from that in the supergravity hydrolysis reaction phase separator. The step-by-step decrease in acidity effectively reduces the chlorine content in the product hydrolyzate, increases the loop ratio of the product, and reduces the product viscosity.

[0031] Specifically, the novel double-stage reaction separation coupling supergravity device (4) comprises: a motor (25), which drives the rotating filling rotor to rotate; an inner and outer double-ring rotating filling rotor (26), wherein the double-ring structure satisfies the staged hydrolysis reaction, wherein the raw material dimethyldichlorosilane and the dilute acid mixture and the concentrated acid enter from the center of the inner ring rotor and the annular gap between the inner and outer rotors respectively, wherein the inner ring of the filler performs the first stage of dilute acid hydrolysis reaction, and the outer ring performs the second stage of concentrated acid hydrolysis reaction; a central jet tube (27), which is located at the center of the inner ring rotor and has a plurality of orifices thereon, wherein the oil-water two-phase mixed liquid composed of the raw material dimethyldichlorosilane and the dilute acid is jetted from the orifices to the surrounding inner ring filler layer; a single-side jet tube (28), which is located in the inner and outer ring gaps of the rotating filling rotor and has a plurality of orifices thereon, wherein the concentrated acid is jetted from the orifice to the outer ring filler. The invention discloses a funnel-shaped inner cylinder wall (5), wherein the mixed liquid carries the hydrogen chloride gas generated by the reaction and is thrown onto the funnel-shaped inner wall under the action of centrifugal force, and the swirling liquid flows downward; the outer cylinder wall (6), which is fixed on the outer kettle body, has a phase separation cavity between it and the inner cylinder wall, and is provided with a gas outlet (34) at the upper part of the side, a middle liquid inlet (35) and a light phase liquid outlet (36) at the middle part of the side, and a heavy phase liquid outlet (37) at the bottom; a concentrated acid guide pipe (29), which is a 90° elbow pipe, connecting the first liquid inlet (32) and the second liquid inlet (33) at the top with the single-side jet pipe (28); a raw material guide pipe (30), which is a 90° elbow pipe, connecting the middle liquid inlet (35) and the center jet pipe (27); and an outer kettle body (31), which can pass a heating or cooling medium.

[0032] Specifically, the ultra-gravity hydrolysis reaction phase separator (12) and the ultra-gravity water washing reaction phase separator (21) include: a rotating filling rotor and a motor; a central jet pipe located at the center of the rotor, with a plurality of orifices opened thereon, from which the oil-water mixed liquid is ejected toward the packing layer; funnel-shaped inner cylinder walls (13) and (22), on which the mixed liquid is thrown onto the funnel-shaped inner walls under the action of centrifugal force, and the swirling liquid flows downward, and the oil-water two phases are quickly separated; outer cylinder walls (14) and (23), which are fixed on the outer kettle body, and a phase separation cavity is formed between the outer cylinder walls and the inner cylinder walls, wherein a light phase liquid outlet and a liquid inlet are provided in the middle of the side thereof, and a heavy phase liquid outlet is provided at the bottom; a liquid guide pipe, which is a 90° elbow pipe, connecting the liquid inlet and the central jet pipe; and the outer kettle body, which can pass a heating or cooling medium.

[0033] Specifically, the hydrolysis includes but is not limited to hydrolysis of chloroorganosilicon such as dimethyldichlorosilane hydrolysis, trimethylchlorosilane hydrolysis, and methylchlorosilane hydrolysis.

[0034] Specifically, the concentration of the fresh feed concentrated hydrochloric acid solution is 40% to 45%, preferably 42% to 45%, the volume ratio of the fresh feed dimethyldichlorosilane to concentrated hydrochloric acid is 1:10 to 1:20, preferably 1:15 to 1:20, the concentration of the circulating dilute hydrochloric acid solution obtained by the secondary hydrolysis phase separation is 20% to 30%, and the volume ratio of the fresh feed dimethyldichlorosilane to dilute hydrochloric acid is 1:0.5 to 1:2, preferably 1:0.5 to 1:1.5.

[0035] Specifically, the concentration of the circulating concentrated hydrochloric acid solution obtained by the primary hydrolysis phase separation is 40% to 45%, the concentration of the circulating dilute hydrochloric acid solution obtained by the secondary hydrolysis phase separation is 20% to 30%, the concentration of the circulating dilute hydrochloric acid solution obtained by the primary water washing phase separation is 2% to 6%, and the concentration of the circulating dilute hydrochloric acid solution obtained by the secondary water washing phase separation is 0.01% to 0.1%.

[0036] Specifically, the washing and degassing pressure is controlled at 0.08 MPa to 0.1 MPa, and the concentration of the obtained concentrated hydrochloric acid solution is 42% to 47%.

[0037] Specifically, the reaction temperature in the novel first-stage hydrolysis phase separation two-stage reaction separation coupled supergravity equipment is controlled at 30° C. to 40° C., and the pressure is controlled at 0.15 MPa to 0.30 MPa.

[0038] Specifically, the temperature in the secondary hydrolysis phase separation high gravity hydrolysis reaction phase separator is controlled at 35°C to 50°C, the temperature in the primary water washing phase separation water washing turntable tower is controlled at 60°C to 90°C, and the temperature in the secondary water washing phase separation high gravity water washing reaction phase separator is controlled at 60°C to 90°C.

[0039] (3) Beneficial technical effects

[0040] (1) Product viscosity and chloride ion content are reduced. In the present invention, the hydrolysis part adopts a new type of double-stage reaction separation coupled with supergravity equipment. Concentrated acid and dilute acid enter the reactor separately. The pre-reaction of dilute acid with raw material dimethyldichlorosilane effectively improves the loop ratio of the product, reduces the product viscosity, and makes the product more competitive. The water washing part adopts a water washing turntable tower and a supergravity water washing reaction phase separator to perform two-stage countercurrent water washing. The multi-stage tower plate balance in the turntable tower effectively reduces the chloride ion content in the hydrolyzate; in the supergravity water washing reaction phase separator, the two-phase material entering from the center jet is sheared at high speed by the rotating filling rotor, and the oil and water phase surfaces are quickly broken and renewed. The crude hydrolyzate is quickly and fully contacted with the desalted water, making the water washing more thorough, ensuring a lower chloride ion content in the final product hydrolyzate.

[0041] (2) The purity of hydrogen chloride recovery is improved. Before the hydrolysis reaction is complete, organochlorosilane molecules will diffuse into the hydrogen chloride gas and be carried out, affecting the gas phase recovery of hydrogen chloride. The present invention uses a new type of supergravity equipment to increase the mass transfer rate at the two-phase interface, accelerate the reaction of dimethylformamide and water, make the hydrolysis more complete, and effectively reduce the entrainment of small molecular siloxane oil substances into the hydrogen chloride recovery gas. At the same time, concentrated acid is used for washing and degassing to further ensure the purity of the recovered gas, so that it can be directly used for chloromethane synthesis, reducing production costs.

[0042] (3) Shortened reaction time and reduced investment costs. The present invention uses high-gravity equipment. On the one hand, compared with conventional reactors, the liquid residence time is drastically shortened, making it more suitable for rapid reactions and improving production efficiency. On the other hand, the smaller equipment volume and efficient reaction separation significantly save investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0044] Figure 1 A schematic diagram of a process system for hydrolyzing dimethyldichlorosilane in an embodiment of the present invention is shown.

[0045] Figure 2 A schematic diagram of a novel dual-stage reaction separation coupling supergravity device in an embodiment of the present invention is shown.

[0046] Figure numerals: 1-concentrated acid feed pump, 2-dimethyldichlorosilane feed pump, 3-desalted water feed pump, 4-new type two-stage reaction separation coupling supergravity equipment, 5-new type two-stage reaction separation coupling supergravity equipment inner cylinder wall, 6-new type two-stage reaction separation coupling supergravity equipment outer cylinder wall, 7-connecting pipe, 8-fine phase tank, 9-concentrated acid circulation pump, 10-washing tower, 11-first crude hydrolyzate delivery pump, 12-supergravity hydrolysis reaction phase separator, 13-supergravity hydrolysis reaction phase separator inner cylinder wall, 14-supergravity hydrolysis reaction phase separator outer cylinder wall, 15-diluted acid cooler, 16-first dilute acid circulation pump, 17-second crude hydrolyzate delivery pump, 18-water washing turntable tower, 19-second dilute acid circulation pump, 20-third crude hydrolyzate delivery pump, 21-supergravity water washing reaction phase separator, 22-inner cylinder wall of supergravity water washing reaction phase separator, 23-outer cylinder wall of supergravity water washing reaction phase separator, 24-third dilute acid circulation pump, 25-motor, 26-inner and outer double-ring rotating filling rotor, 27-central jet tube, 28-single-side jet tube, 29-concentrated acid guide tube, 30-raw material guide tube, 31-outer kettle body, 32-first liquid inlet at the top, 33-second liquid inlet at the top, 34-gas outlet, 35-middle liquid inlet, 36-light phase liquid outlet, 37-heavy phase liquid outlet. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and do not limit the present invention in any way. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0048] The present invention is illustrated below with specific scenario cases.

[0049] Example 1

[0050] The system and method of the present invention are used to hydrolyze dimethyldichlorosilane, pass the desalted water into a supergravity water washing reaction phase separator, pass the raw dimethyldichlorosilane and fresh concentrated hydrochloric acid solution into a novel two-stage reaction separation coupling supergravity device, and after the system is stable, adopt the following operating conditions: the concentration of the fresh feed concentrated hydrochloric acid solution is 42%, and the volume ratio of the fresh feed dimethyldichlorosilane to the concentrated hydrochloric acid is 1:15; the concentration of the circulating dilute hydrochloric acid solution obtained by the secondary hydrolysis phase separation is 28%, and the volume ratio of the fresh feed dimethyldichlorosilane to the dilute hydrochloric acid is 1:0.8; the concentration of the circulating concentrated hydrochloric acid solution obtained by the primary hydrolysis phase separation is 42% to 45%, and the circulating dilute hydrochloric acid obtained by the primary water washing phase separation is 1:15. The solution concentration is 2% to 6%, and the concentration of the circulating dilute hydrochloric acid solution obtained by the secondary water washing phase separation is 0.01% to 0.1%; the washing degassing pressure is controlled at 0.08Mpa to 0.1Mpa, and the concentration of the obtained concentrated hydrochloric acid solution is 42% to 47%; the reaction temperature in the new double-stage reaction separation coupled supergravity equipment for the first-stage hydrolysis phase separation is controlled at 30°C to 40°C, and the pressure is controlled at 0.15Mpa to 0.30Mpa; the temperature in the supergravity hydrolysis reaction phase separator of the second-stage hydrolysis phase separation is controlled at 35°C to 50°C, the temperature in the water washing rotary disk tower of the first-stage water washing phase separation is controlled at 60°C to 90°C, and the temperature in the supergravity water washing reaction phase separator of the second-stage water washing phase separation is controlled at 60°C to 90°C.

[0051] After the system was in steady-state operation, a continuous output of hydrolyzed polydimethylsiloxane was obtained. Analysis showed that its viscosity ν was 18 cp, the chlorine content α was 4 ppm, and the residual polysiloxane concentration β in the recovered hydrogen chloride gas was 45 ppm.

[0052] Examples 2 to 10: The process flow and steps are the same as those in Example 1, and the parameters of the relevant process are adjusted, as follows.

[0053] Table 1 Process conditions and experimental results of Examples 2 to 10

[0054] Example A(％) B C ν(cp) α(ppm) β(ppm) 2 45 1:18 1:0.8 21 5 44 3 42 1:15 1:0.5 19 6 46 4 42 1:15 1:1.5 17 4 47 5 40 1:12 1:0.8 15 4 48 6 42 1:15 1:2 17 3 47 7 47 1:20 1:0.8 28 8 44 8 42 1:15 1:5 25 3 50

[0055] A-concentration of fresh feed concentrated hydrochloric acid solution; B-volume ratio of fresh feed dimethyldichlorosilane to concentrated hydrochloric acid; C-volume ratio of fresh feed dimethyldichlorosilane to dilute hydrochloric acid; ν-viscosity of hydrolyzed polydimethylsiloxane; α-chlorine content of hydrolyzed polydimethylsiloxane; β-concentration of residual polysiloxane in the recovered hydrogen chloride gas.

[0056] Among all the examples, Examples 1 to 4 are within the process parameter range claimed by the present invention. From the results of the examples, it can be concluded that the viscosity and chloride ion content of the dimethyldichlorosilane hydrolysis product are low, the purity of the recovered hydrogen chloride gas is high, and the overall effect is excellent.

[0057] In all the examples, the process operation parameters of Examples 5 and 6 are not within the optimal range. It can be seen from the results of the examples that the increase in the pH value of the hydrolysis reaction further reduces the chlorine content of the product and improves the product quality. However, considering that more hydrogen chloride dissolves and releases heat, in order to maintain a lower reaction temperature for hydrolysis, this solution causes more material and energy consumption.

[0058] In all embodiments, the process operating parameters of Examples 7 to 8 are outside the process parameter range claimed by the present invention. It can be concluded from the results of the embodiments that deviation from the process operating parameter range claimed by the present invention will significantly affect at least one technical indicator or cause more energy consumption.

[0059] The various embodiments in this specification are described in a progressive manner. Similar portions between the various embodiments can be referenced to each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiment is generally similar to the method embodiment, so the description is relatively simple. For relevant portions, refer to the description of the method embodiment.

[0060] In the description of this specification, reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example.

[0061] In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, unless they are mutually inconsistent. The above description is merely an embodiment of the embodiment of this specification and is not intended to limit the embodiment of this specification. For those skilled in the art, various changes and modifications may be made to the embodiment of this specification. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiment of this specification shall be included within the scope of the claims of the embodiment of this specification.

Claims

1. A system for hydrolyzing dimethyldichlorosilane, which is an equipment system for realizing the hydrolysis process of dimethyldichlorosilane, characterized in that: Includes the following devices and connections: Concentrated acid feed pump (1), dimethyldichlorosilane feed pump (2), desalted water feed pump (3), two-stage reaction separation coupling supergravity equipment (4), connecting pipe (7), fine phase tank (8), concentrated acid circulation pump (9), washing tower (10), first crude hydrolyzate delivery pump (11), supergravity hydrolysis reaction phase separator (12), dilute acid cooler (15), first dilute acid circulation pump (16), second crude hydrolyzate delivery pump (17), water washing rotary tower (18), second dilute acid circulation pump (19), third crude hydrolyzate delivery pump (20), supergravity water washing reaction phase separator (21), third dilute acid circulation pump (24); In order to meet the phase separation requirements, the two-stage reaction separation coupling supergravity device (4) is provided with a two-stage reaction separation coupling supergravity device inner cylinder wall (5) and a two-stage reaction separation coupling supergravity device outer cylinder wall (6) at the lower middle part of the device, and three-phase coarse phase separation is completed between the inner and outer cylinder walls; In order to meet the phase separation requirements, the high-gravity hydrolysis reaction phase separator (12) is provided with an inner cylinder wall (13) of the high-gravity hydrolysis reaction phase separator and an outer cylinder wall (14) of the high-gravity hydrolysis reaction phase separator, so as to complete two-phase phase separation between the inner and outer cylinder walls; In order to meet the phase separation requirements, the high-gravity water washing reaction phase separator (21) is provided with an inner cylinder wall (22) of the high-gravity water washing reaction phase separator and an outer cylinder wall (23) of the high-gravity water washing reaction phase separator, and two-phase separation is completed between the inner and outer cylinder walls; The system connection sequence is: A two-stage reaction separation coupled high-gravity device, wherein the first liquid inlet at the top is connected to the concentrated acid inlet and the coarse and fine phase heavy phase liquid outlets respectively through a concentrated acid feed pump and a concentrated acid circulation pump, the second liquid inlet at the top is connected to the liquid outlet of the washing tower, the gas outlet is connected to the gas inlet of the washing tower, the middle liquid inlet is connected to the dimethyldichlorosilane inlet through a dimethyldichlorosilane feed pump, and is connected to the heavy phase liquid outlet of the high-gravity hydrolysis reaction phase separator through a dilute acid cooler and a first dilute acid circulation pump, the middle light phase liquid outlet is connected to the fine phase tank through a connecting pipe, and the bottom heavy phase liquid outlet is connected to the first liquid inlet at the top and the liquid inlet of the washing tower through a concentrated acid circulation pump; The washing tower has a liquid inlet connected to the concentrated acid inlet and the coarse and fine phase heavy phase liquid outlets through a concentrated acid feed pump and a concentrated acid circulation pump, respectively; its liquid outlet is connected to the second liquid inlet at the top of the two-stage reaction separation coupling high gravity equipment; its gas inlet is connected to the coarse and fine phase gas outlets; and its gas outlet is the hydrogen chloride gas outlet; A fine phase separation tank, wherein the material inlet of the fine phase separation tank is connected to the light phase liquid outlet in the middle of the two-stage reaction separation coupling high gravity device through a connecting pipe, the gas outlet of the fine phase separation tank is connected to the gas inlet of the washing tower, the light phase liquid outlet of the fine phase separation tank is connected to the liquid inlet of the high gravity hydrolysis reaction phase separator through a first crude hydrolyzate delivery pump, and the heavy phase liquid outlet of the fine phase separation tank is connected to the first liquid inlet at the top of the two-stage reaction separation coupling high gravity device and the liquid inlet of the washing tower through a concentrated acid circulation pump; The liquid inlet of the high-gravity hydrolysis reaction phase separator is connected to the light phase liquid outlet of the fine phase separation tank and the heavy phase liquid outlet of the water washing turntable tower respectively through the first crude hydrolyzate delivery pump and the second dilute acid circulation pump; the light phase liquid outlet is connected to the light phase liquid inlet of the water washing turntable tower through the second crude hydrolyzate delivery pump, and the heavy phase liquid outlet is connected to the liquid inlet of the middle part of the two-stage reaction separation coupling high-gravity equipment through the dilute acid cooler and the first dilute acid circulation pump; a water washing turntable tower, wherein the light phase liquid inlet is connected to the light phase liquid outlet of the supergravity hydrolysis reaction phase separator via a second crude hydrolyzate delivery pump, the heavy phase liquid inlet is connected to the heavy phase liquid outlet of the supergravity water washing reaction phase separator via a third dilute acid circulation pump, the light phase liquid outlet is connected to the liquid inlet of the supergravity water washing reaction phase separator via the third crude hydrolyzate delivery pump, and the heavy phase liquid outlet is connected to the liquid inlet of the supergravity hydrolysis reaction phase separator via a second dilute acid circulation pump; The liquid inlet of the ultra-gravity water washing reaction phase separator is connected to the desalted water inlet and the light phase liquid outlet of the water washing turntable tower through the desalted water feed pump and the third crude hydrolyzate delivery pump respectively. The light phase liquid outlet is the hydrolyzate outlet, and the heavy phase liquid outlet is connected to the heavy phase liquid inlet of the water washing turntable tower through the third dilute acid circulation pump.

2. A method for producing dimethyldichlorosilane hydrolysis, for realizing a system for hydrolyzing dimethyldichlorosilane according to claim 1, characterized in that: The following steps are involved: (1) The concentrated acid of the fresh feed for washing and degassing is mixed with the concentrated acid obtained from the primary hydrolysis of the coarse and fine phases and introduced into the top of the washing tower. In the tower, it contacts with the impure hydrogen chloride gas from the primary hydrolysis of the coarse and fine phases in the overall countercurrent and partial crosscurrent to complete the washing and degassing work; the hydrogen chloride gas with impurities of small molecular siloxane oil substances removed passes through the demister and leaves the washing tower from the gas outlet at the top of the tower, and the concentrated acid is extracted from the bottom of the tower and sent to the outer ring packing of the double-stage reaction separation coupling supergravity equipment for the second stage of concentrated acid hydrolysis reaction; (2) The first stage super gravity double-stage hydrolysis reaction phase separation fresh feed of dimethyldichlorosilane and the dilute acid obtained from the second stage hydrolysis phase separation mixed feed are introduced into the double-stage reaction separation coupled super gravity equipment. The two-phase material entering through the central jet is rapidly sheared by the inner ring rotating filling rotor. The oil-water two-phase surface is quickly broken and renewed. The dimethyldichlorosilane and the dilute acid are quickly and fully mixed to carry out the first stage dilute acid hydrolysis reaction. The fresh feed of concentrated acid and the concentrated acid obtained from the coarse and fine phases of the first stage hydrolysis are mixed into the double-stage reaction separation coupled super gravity equipment. The material enters the annular gap and is jetted to the outer ring rotating filling rotor. It is quickly and fully mixed with the material that has completed the first stage dilute acid hydrolysis reaction to carry out the second stage concentrated acid hydrolysis reaction. Subsequently, the mixed liquid that has completed the two-stage reaction through the packing layer carries the hydrogen chloride gas generated by the reaction and is thrown onto the inner cylinder wall of the two-stage reaction separation coupling high-gravity equipment under the action of centrifugal force. The swirling liquid flows downward, and the impure hydrogen chloride gas is discharged from the gas outlet set on the side of the outer cylinder wall through the gap between the inner and outer cylinders, thereby achieving gas-liquid separation; at the bottom of the equipment shell, the oil and water phases are roughly separated, and the crude oil phase flows into the fine phase tank through a connecting pipe for fine phase separation. The concentrated acid of the aqueous phase is extracted from the bottom and mixed with the concentrated acid from the fine phase tank and sent to the washing tower and the outer ring packing of the two-stage reaction separation coupling high-gravity equipment; the light phase first crude hydrolyzate obtained by phase separation in the fine phase tank is sent to the high-gravity hydrolysis reaction phase separator for second-stage hydrolysis and phase separation; (3) Second stage super gravity hydrolysis reaction phase separation The light phase first crude hydrolyzate obtained by the above phase separation and the dilute acid mixed feed from the first stage water washing are introduced into the super gravity hydrolysis reaction phase separator. The two phases of materials entering through the central jet are quickly and fully mixed, and a dilute acid hydrolysis reaction is carried out to generate hydrogen chloride dissolved in the liquid phase. No gas escapes during the process. The mixed liquid that completes the hydrolysis reaction after passing through the packing layer is thrown onto the inner wall of the super gravity hydrolysis reaction phase separator under the action of centrifugal force, and the swirling liquid flows downward, and the oil and water phases are quickly separated. At the bottom of the rotating filling rotor housing, the oil and water phases are separated, wherein the second crude hydrolyzate is discharged as the light component of the oil phase from the light phase liquid outlet on the side of the outer cylinder wall, and the dilute acid is discharged as the heavy component of the water phase from the heavy phase liquid outlet at the bottom; (4) Phase separation of the water washing reaction in the first-stage water washing rotary disc tower: The light phase second crude hydrolyzate obtained by the above phase separation and the dilute acid from the second-stage water washing are respectively introduced into the bottom and top of the water washing rotary disc tower as the light and heavy phases, and are contacted with each other in countercurrent in the tower for water washing and separation. Under the agitation of the fixed rotary disc, the dispersed phase forms small droplets, which increases the mass transfer area. After the process is completed, the light phase third crude hydrolyzate and the heavy phase dilute acid are discharged from the liquid outlets at the top and bottom of the tower respectively; (5) Second-stage supergravity water washing reaction phase separation The light phase third crude hydrolyzate obtained by the above phase separation is mixed with the fresh desalted water and fed into the supergravity water washing reaction phase separator. The reaction and separation process are similar to those in the supergravity hydrolysis reaction phase separator. The hydrolyzate is discharged as the light component of the oil phase at the light phase liquid outlet on the side of the outer cylinder wall, and the dilute acid is discharged as the heavy component of the water phase at the heavy phase liquid outlet at the bottom. However, the pH value in the supergravity water washing reaction phase separator is significantly different from that in the supergravity hydrolysis reaction phase separator. The step-by-step decrease in acidity effectively reduces the chlorine content in the product hydrolyzate, increases the product loop ratio, and reduces the product viscosity.

3. The hydrolysis system according to claim 1, characterized in that The dual-stage reaction separation coupled supergravity device (4) comprises: a motor (25) for driving a rotating filling rotor to rotate; an inner and outer double-ring rotating filling rotor (26), wherein the double-ring structure satisfies a staged hydrolysis reaction, wherein the raw material dimethyldichlorosilane and the dilute acid mixture and the concentrated acid enter from the center of the inner ring rotor and the annular gap between the inner and outer rotors respectively, wherein the inner ring of the filler performs a first stage of dilute acid hydrolysis reaction, and the outer ring performs a second stage of concentrated acid hydrolysis reaction; a central jet pipe (27) located at the center of the inner ring rotor, wherein a plurality of orifices are opened on the central jet pipe, wherein the oil-water two-phase mixed liquid consisting of the raw material dimethyldichlorosilane and the dilute acid is ejected from the orifice to the surrounding inner ring filler layer; a single-side jet pipe (28) located in the inner and outer ring gaps of the rotating filling rotor, wherein a plurality of orifices are opened on the central jet pipe, wherein the concentrated acid is ejected from the orifice to the outer ring filler layer; an inner cylinder of the dual-stage reaction separation coupled supergravity device The mixed liquid carries the hydrogen chloride gas generated by the reaction and is thrown onto the inner cylinder wall of the double-stage reaction separation coupling supergravity device under the action of centrifugal force, and the swirling liquid flows downward; the outer cylinder wall (6) of the double-stage reaction separation coupling supergravity device is fixed on the outer kettle body, and a phase separation cavity exists between the outer cylinder wall and the inner cylinder wall, and a gas outlet (34) is provided on the upper part of the side, a middle liquid inlet (35) and a light phase liquid outlet (36) are provided on the middle part of the side, and a heavy phase liquid outlet (37) is provided on the bottom; the concentrated acid guide pipe (29) is a 90° elbow pipe, which is connected to the first liquid inlet (32) and the second liquid inlet (33) at the top and the single-side jet pipe (28); the raw material guide pipe (30) is a 90° elbow pipe, which is connected to the middle liquid inlet (35) and the center jet pipe (27); the outer kettle body (31) can pass a heating or cooling medium.

4. The hydrolysis system according to claim 1, characterized in that The supergravity hydrolysis reaction phase separator (12) and the supergravity water washing reaction phase separator (21) comprise: a rotating filling rotor and a motor; a central jet pipe located at the center of the rotor, with a plurality of orifices formed thereon, through which the oil-water mixed liquid is jetted toward the packing layer; an inner cylinder wall (13) of the supergravity hydrolysis reaction phase separator and an inner cylinder wall (22) of the supergravity water washing reaction phase separator, through which the mixed liquid is thrown onto the funnel-shaped inner cylinder wall under the action of centrifugal force, and the swirling liquid flows downward, and the oil-water two phases are quickly separated; an outer cylinder wall (14) of the supergravity hydrolysis reaction phase separator and an outer cylinder wall (23) of the supergravity water washing reaction phase separator are fixed on the outer kettle body, with a phase separation cavity formed between the outer cylinder wall and the inner cylinder wall, a light phase liquid outlet and a liquid inlet being provided in the middle of the side thereof, and a heavy phase liquid outlet being provided at the bottom; a liquid guide pipe having a 90° elbow structure, connecting the liquid inlet and the central jet pipe; and an outer kettle body capable of passing a heating or cooling medium.

5. The hydrolysis system according to claim 1, characterized in that The hydrolysis includes hydrolysis of dimethyldichlorosilane, hydrolysis of trimethylchlorosilane, hydrolysis of methylchlorosilane or hydrolysis of chloroorganosilicon.

6. The production method of dimethyldichlorosilane hydrolysis according to claim 2, characterized in that: The concentration of the freshly fed concentrated acid solution is 40% to 45%, the volume ratio of the freshly fed dimethyldichlorosilane to the concentrated acid is 1:10 to 1:20, the concentration of the circulating dilute acid solution obtained by the secondary hydrolysis phase separation is 20% to 30%, and the volume ratio of the freshly fed dimethyldichlorosilane to the dilute acid is 1:0.5 to 1:

2.

7. The production method of dimethyldichlorosilane hydrolysis according to claim 2, characterized in that: The concentration of the circulating concentrated acid solution obtained by the primary hydrolysis of the coarse and fine phases is 40% to 45%, the concentration of the circulating dilute acid solution obtained by the secondary hydrolysis phase separation is 20% to 30%, the concentration of the circulating dilute acid solution obtained by the primary water washing phase separation is 2% to 6%, and the concentration of the circulating dilute acid solution obtained by the secondary water washing phase separation is 0.01% to 0.1%.

8. The production method of hydrolyzing dimethyldichlorosilane according to claim 2, characterized in that: The washing and degassing pressure is controlled at 0.08 MPa to 0.1 MPa, and the concentration of the obtained concentrated acid solution is 42% to 47%.

9. The production method of dimethyldichlorosilane hydrolysis according to claim 2, characterized in that: The reaction temperature in the primary hydrolysis coarse and fine phase two-stage reaction separation coupled high gravity equipment is controlled at 30° C. to 40° C., and the pressure is controlled at 0.15 MPa to 0.30 MPa.

10. The production method of dimethyldichlorosilane hydrolysis according to claim 2, characterized in that: The temperature in the secondary hydrolysis phase separation high gravity hydrolysis reaction phase separator is controlled at 35°C-50°C, the temperature in the primary water washing phase separation water washing turntable tower is controlled at 60°C-90°C, and the temperature in the secondary water washing phase separation high gravity water washing reaction phase separator is controlled at 60°C-90°C.

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