A kind of preparation process of phenyl polytrimethylsiloxane

Abstract

The invention discloses a phenyl polytrimethylsiloxane preparation process, and relates to the technical field of phenyl polytrimethylsiloxane preparation. The process comprises the following steps: S1. heating treatment: a flask filled with pure water is heated by an oil bath heating device; S2. dripping and mixing: a temperature detection device is used to detect the temperature of the solution in the flask, and when the temperature reaches a preset value, a mixture of trimethylchlorosilane and phenyltrichlorosilane is dripped into the flask in succession by a constant pressure dripping component; S3. hydrolysis reaction: the solution in the flask is stirred and mixed, so that the solution in the flask undergoes a hydrolysis reaction at high temperature; S4. oil-water separation; S5. oil phase distillation. Compared with the traditional phenyl polytrimethylsiloxane preparation process, the present invention optimizes the dripping and mixing steps, so that the prepared phenyl polytrimethylsiloxane has higher precision, and avoids the problem of experimental failure due to the influence of factors such as temperature.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of phenyl polytrimethylsiloxane, and in particular to a preparation process of phenyl polytrimethylsiloxane. Background Art

[0002] The preparation of phenyl polytrimethylsiloxane has been gradually developed under the background of continuous progress in the field of polymer material science. This material has shown broad application prospects in aerospace, electronics, automobiles, medical and other fields due to its excellent thermal stability, chemical stability, electrical insulation and weather resistance.

[0003] In the prior art, when preparing phenyl trimethylsiloxane, an oil bath heating device is usually used to heat a reaction bottle, and a constant pressure dropping funnel is connected above the reaction bottle to drop phenyl trichlorosilane and trimethyl chlorosilane into the reaction bottle for hydrolysis reaction. This method involves hydrolyzing phenyl trichlorosilane and trimethyl chlorosilane under appropriate conditions to form phenyl trimethylsiloxane.

[0004] However, when phenyl polytrimethylsiloxane is prepared by the above-mentioned oil bath equipment, since the oil bath heating device will generate a large amount of heat energy when heating the reaction bottle, and the reaction bottle and the constant pressure dropping funnel are sealed, the heat energy will heat the gas in the reaction bottle and the constant pressure dropping funnel, causing the gas inside to expand due to the heat. When the reaction liquid is added to the reaction bottle through the constant pressure dropping funnel, the expanding gas will push the reaction liquid to flow rapidly, resulting in the inability to accurately control the amount of reaction liquid added to the reaction bottle each time, and under continuous heating, the gas in the reaction bottle and the constant pressure dropping funnel will gradually expand, which can easily cause the reaction bottle or the constant pressure dropping funnel to break under the action of air pressure.‌

[0005] Therefore, it is necessary to invent a phenyl polytrimethylsiloxane preparation process to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a process for preparing phenyl polytrimethylsiloxane to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a process for preparing phenyl polytrimethylsiloxane, comprising the following steps:

[0008] S1. Heating treatment: The flask containing pure water was heated using an oil bath heating device;

[0009] S2. Dropping and mixing: The temperature of the solution in the flask is detected by a temperature detection device. When the temperature reaches a preset value, a mixture of trimethylchlorosilane and phenyltrichlorosilane is added dropwise to the flask using a constant pressure drip assembly;

[0010] S3 hydrolysis reaction: The solution in the flask is stirred and mixed, and the solution in the flask is hydrolyzed at high temperature;

[0011] S4. Oil-water separation: After the reaction of the solution in the flask is completed, the flask is allowed to stand and the lower aqueous phase is discharged;

[0012] S5. Oil phase distillation: The oil phase in the flask was added to the distillation reactor for distillation to obtain phenyl trimethylsiloxane;

[0013] The constant pressure drip assembly comprises a cylinder provided with a liquid inlet and a liquid outlet, a connecting piece is fixedly connected to the liquid outlet at the bottom of the cylinder, a dripping tube is fixedly connected to the bottom of the connecting piece, a constant pressure chamber is sleeved on the outside of the dripping tube, a sealing plug is sleeved on the outside of the bottom of the constant pressure chamber, and a sealing assembly is provided at the bottom of the sealing plug;

[0014] The sealing assembly includes a connecting plate, a through hole is formed in the middle of the upper end of the connecting plate, a polygonal slide groove is formed on the upper end of the connecting plate and located outside the through hole, a plurality of slide rods are movably connected in the polygonal slide groove, a sealing member is fixedly connected to the outer side of each slide rod, and the plurality of sealing members are attached to each other and can seal the through hole;

[0015] A driving disk is provided above the sealing member, and a plurality of ventilation pipes are fixedly connected to the driving disk in an annular array, and a plurality of connecting grooves adapted to the ventilation pipes are provided in an annular array on the connecting disk, and an expansion member is provided in each of the connecting grooves, and the ventilation pipe is slidably connected to the connecting groove via the expansion member, and the expansion of the expansion member pushes the ventilation pipe to slide in the connecting groove.

[0016] As a further improvement of the present application, the reaction time of the solution in the flask in S3 is 1.5-3 hours.

[0017] As a further improvement of the present application, after the reaction of the solution in the flask in S4 is completed, the solution is allowed to stand for 50-70 minutes.

[0018] As a further improvement of the present application, the oil bath heating device is provided with a clamping assembly, and the clamping assembly respectively clamps the constant pressure dripping assembly and the flask, and the flask is located below the constant pressure dripping assembly.

[0019] As a further improvement of the present application, a connecting valve is provided in the middle of the connecting piece, and the drip tube is connected with the interior of the cylinder through the connecting piece. A connecting pipe is fixedly connected to one side of the constant pressure chamber, and the constant pressure chamber is connected with the cylinder through the connecting pipe. The sealing plug includes a plug body, and a plurality of air outlet holes are opened in a circular array on the axial side of the plug body.

[0020] As a further improvement of the present application, the outer side of the connecting disk is fixedly connected to the inner wall of the plug body, and the number of the sliding rods is the same as the number of sides of the polygonal sliding groove.

[0021] As a further improvement of the present application, the driving disk is provided with limiting grooves having the same number as the sliding rods.

[0022] As a further improvement of the present application, the oil bath heating device also includes a control console, a heating assembly is provided above the control console, an oil bath pot is provided in the middle of the heating assembly, a detection assembly for detecting the water level of the heating liquid and a supply assembly for replenishing the heating liquid are provided in the oil bath pot.

[0023] As a further improvement of the present application, the clamping assembly also includes a mounting seat, which is fixed above the oil bath heating device. A mounting rod is provided on the top of the mounting seat, and a plurality of sliding seats are slidably connected to the mounting rod. A locking screw is provided on one side of each sliding seat, and the other end of each sliding seat is rotatably connected to a rotating member, and a connecting support rod is provided on the rotating member, and a claw is movably connected to the end of the connecting support rod away from the rotating member.

[0024] As a further improvement of the present application, the clamping claw includes two symmetrically arranged connecting arms, and a plurality of threaded rods for adjusting the spacing between the connecting arms are provided in a linear array between two adjacent connecting arms; one end of the connecting arm movably connected to the connecting support rod is provided with a limiting mechanism for limiting the rotation of the connecting arm; and the end of the connecting arm away from the connecting support rod is provided with a clamping plate.

[0025] Technical effects and advantages of the present invention:

[0026] 1. Compared with the traditional preparation process of phenyl trimethicone, the present invention optimizes the dripping and mixing steps, so that the prepared phenyl trimethicone has higher precision and avoids the problem of experimental failure caused by factors such as temperature.

[0027] 2. The present invention cooperates with devices such as a sealing plug and a sealing component. When the sealing plug needs to be inserted into a flask, the side wall of the sealing plug will be deformed and fit the flask due to the multiple air outlet holes, while the bottom of the sealing plug will limit the deformation of the sealing plug due to the sealing component, thereby avoiding the problem that in the subsequent heating process, the sealing component is deformed due to heat, causing the inside of the flask to contact with external gas and affecting the preparation effect.

[0028] 3. The present invention cooperates with the sealing plug and the sealing assembly and other devices. When the solution in the flask is heated and reacted, the rotating driving disk synchronously drives the multiple limit grooves to rotate, so that the sliding rod connected to the limit groove slides in the polygonal sliding groove, and the multiple sealing parts that fit each other are moved, thereby reducing the aperture of the through hole in disguise. The diameter of the liquid outlet of the dropper is changed by the movement of the sealing part, and then the flow rate of the dropper is limited, so as to avoid the problem that the expanded gas drives the reaction liquid to flow quickly, resulting in the problem that the amount of reaction liquid dripped into the reaction bottle each time cannot be accurately controlled, affecting the preparation accuracy.

[0029] 4. The present invention uses the mutual cooperation of the sealing plug and the sealing assembly and other devices to discharge the gas in the flask and the expansion member through the ventilation pipe through the expansion member, thereby reducing the air pressure in the flask and the expansion member, thereby avoiding the problem that the gas in the flask and the constant-pressure drip assembly gradually expands and causes the flask or the constant-pressure drip assembly to break under the action of air pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the process flow of phenyl polytrimethylsiloxane of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the device for preparing phenyl polytrimethylsiloxane of the present invention;

[0032] Figure 3 This is a schematic diagram of the structure of a constant pressure dripping component in the preparation device of the present invention;

[0033] Figure 4 It is a schematic diagram of the explosion structure of the constant pressure dripping assembly in the preparation device of the present invention;

[0034] Figure 5 It is a schematic diagram of the connection structure between the sealing component and the sealing plug in the constant pressure drip assembly of the present invention;

[0035] Figure 6 It is a schematic diagram of the explosion structure of the sealing component in the constant pressure dripping component of the present invention;

[0036] Figure 7 It is a schematic diagram of the structure of the clamping assembly in the preparation device of the present invention;

[0037] Figure 8 For the present invention Figure 7 Schematic diagram of the structure of the organization at A in the middle;

[0038] Fig. 9 This is a schematic diagram of the closed structure of the sealing member of the present invention;

[0039] Fig.10 This is a schematic diagram of the opening structure of the sealing member of the present invention;

[0040] Fig.11It is a schematic diagram of the connection structure between the expansion member and the connection disk of the present invention.

[0041] In the figure: 10, oil bath heating device; 11, control console; 12, heating assembly; 13, oil bath pot; 20, clamping assembly; 21, mounting seat; 22, mounting rod; 23, sliding seat; 24, locking screw; 25, rotating member; 26, connecting support rod; 27, claw; 271, connecting arm; 272, threaded rod; 273, clamping sheet; 30, constant pressure drip assembly; 31, cylinder; 32, connecting piece ; 33. Connecting valve; 34. Dropping tube; 35. Constant pressure chamber; 36. Connecting pipe; 37. Sealing plug; 371. Plug body; 372. Air vent; 38. Sealing assembly; 381. Connecting disk; 382. Polygonal slide groove; 383. Slide rod; 384. Sealing element; 385. Driving disk; 386. Limiting groove; 387. Ventilation pipe; 388. Connecting groove; 389. Expansion element; 40. Flask. DETAILED DESCRIPTION

[0042] 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Embodiment 1

[0044] Reference Figure 1 In order to prepare phenyl trimethicone, this embodiment provides a process for preparing phenyl trimethicone, comprising the following steps:

[0045] S1. Heating treatment: The flask 40 filled with pure water is heated using an oil bath heating device 10 .

[0046] S2. Dropping and mixing: The temperature of the solution in the flask 40 is detected by a temperature detection device. When the temperature reaches a preset value, a mixture of trimethylchlorosilane and phenyltrichlorosilane is dripped into the flask 40 in batches by a constant pressure dripping assembly 30 .

[0047] S3. Hydrolysis reaction: The solution in the flask 40 is stirred and mixed to allow the solution in the flask 40 to undergo a hydrolysis reaction at a high temperature, wherein the reaction time of the solution in the flask 40 is 1.5-3 hours.

[0048] S4. Oil-water separation: After the reaction of the solution in the flask 40 is completed, the flask 40 is allowed to stand and the lower aqueous phase is discharged. The standing time of the solution in the flask 40 after the reaction is completed is 50-70 minutes.

[0049] S5. Oil phase distillation: The oil phase in the flask 40 is added to the distillation tower kettle for distillation to obtain phenyl polytrimethylsiloxane.

[0050] Compared with the traditional preparation process of phenyl trimethicone, this embodiment optimizes the dripping and mixing steps, controls the heating temperature and controls the flow rate of the dripping tube, so that the prepared phenyl trimethicone has higher accuracy, and avoids the problem of experimental failure due to factors such as temperature and flow rate.

[0051] Embodiment 2

[0052] In order to further realize the excellence of the preparation process of phenyl polytrimethylsiloxane of the present invention, the heating temperature-related components and the flow rate control components of the dropper are optimized and improved. Specifically, the oil bath heating device 10 is used to heat the reaction liquid in the flask 40; the oil bath heating device 10 is provided with a clamping assembly 20 for clamping the flask 40 and the constant pressure drip assembly 30; the clamping assembly 20 clamps the constant pressure drip assembly 30 and the flask 40 respectively, and the flask 40 is located below the constant pressure drip assembly 30, wherein the constant pressure drip assembly 30 is filled with a mixed solution of trimethylchlorosilane and phenyltrichlorosilane, and the flask 40 is filled with pure water required for the reaction.

[0053] Reference Figure 2-Figure 11 The oil bath heating device 10 also includes a control console 11, a heating component 12 is provided above the control console 11, an oil bath pot 13 is provided in the middle of the heating component 12, and a detection component for detecting the water level of the heating liquid and a supply component for replenishing the heating liquid are provided in the oil bath pot 13. Through the setting of the control console 11 and the heating component 12, the heating medium in the oil bath pot 13 is heated, so that the heating medium always maintains the required temperature and continuously provides heat energy to the reaction liquid in the flask 40. When the detection component detects that the heating medium is volatilizing, the heating medium in the oil bath pot 13 is replenished in small amounts and multiple times through the supply component, thereby avoiding the problem of temperature fluctuation caused by excessive single replenishment of the medium.

[0054] The clamping assembly 20 also includes a mounting seat 21, which is fixed above the oil bath heating device 10. A mounting rod 22 is provided on the top of the mounting seat 21, and a plurality of sliding seats 23 are slidably connected to the mounting rod 22. A locking screw 24 is provided on one side of each sliding seat 23, and a rotating member 25 is rotatably connected to the other end of each sliding seat 23. A connecting support rod 26 is provided on the rotating member 25, and a claw 27 is movably connected to the end of the connecting support rod 26 away from the rotating member 25. By threading the locking screw 24 and the sliding seat 23, and making the locking screw 24 pass through the sliding seat 23 and contact the mounting rod 22 at one end close to the mounting rod 22, when the sliding seat 23 needs to be fixed at a certain position on the mounting rod 22, the locking screw 24 is rotated to make the locking screw 24 fit tightly with the mounting rod 22, thereby limiting the sliding seat 23, further improving the convenience of the clamping assembly 20.

[0055] The claw 27 includes two symmetrically arranged connecting arms 271, and a plurality of threaded rods 272 for adjusting the spacing between the connecting arms 271 are arranged in a linear array between two adjacent connecting arms 271. One end of the connecting arm 271 that is movably connected to the connecting support rod 26 is provided with a limiting mechanism for limiting the rotation of the connecting arm 271, and one end of the connecting arm 271 away from the connecting support rod 26 is provided with a clamping piece 273. By arranging a plurality of threaded rods 272 between two adjacent connecting arms 271, when it is necessary to increase the distance between the two adjacent connecting arms 271, the threaded rod 272 is rotated in the reverse direction. At this time, since the threaded rod 272 and the connecting arm 271 are threadedly connected, the two connecting arms 271 will move away from each other, thereby increasing the distance between the two adjacent connecting arms 271. Conversely, rotating the threaded rod 272 forward will reduce the distance between the two adjacent connecting arms 271.

[0056] It should be noted that the limiting mechanism for limiting the rotation of the connecting arm 271 includes but is not limited to electromagnetic latches, card slots, card blocks and other mechanical structures that can achieve limiting in the prior art.

[0057] The constant pressure drip assembly 30 includes a cylinder 31 provided with a liquid inlet and a liquid outlet, a connecting piece 32 is fixedly connected to the liquid outlet at the bottom of the cylinder 31, a connecting valve 33 is provided in the middle of the connecting piece 32, a drip tube 34 is fixedly connected to the bottom of the connecting piece 32, and the drip tube 34 is connected to the inside of the cylinder 31 through the connecting piece 32, a constant pressure bin 35 is sleeved on the outside of the drip tube 34, a connecting pipe 36 is fixedly connected to one side of the constant pressure bin 35, the constant pressure bin 35 is connected to the cylinder 31 through the connecting pipe 36, a sealing plug 37 is sleeved on the outside of the bottom of the constant pressure bin 35, the sealing plug 37 includes a plug body 371, and a plurality of air outlet holes 372 are opened in a circular array on the axial side of the plug body 371.

[0058] When in use, the flask 40 and the constant pressure drip assembly 30 are clamped by the clamping assembly 20, and the positions of the flask 40 and the constant pressure drip assembly 30 are adjusted to move the flask 40 and the constant pressure drip assembly 30 to the top of the oil bath pot 13, so that the flask 40 is in contact with the heating medium in the oil bath pot 13, and the solution in the flask 40 is heated by the oil bath heating device 10. When the temperature reaches the preset temperature, the connecting valve 33 is rotated to connect the cylinder 31 with the drip tube 34 through the connecting piece 32, and the mixed solution of trimethylchlorosilane and phenyltrichlorosilane in the cylinder 31 is dripped into the flask 40 through the drip tube 34 for reaction.

[0059] Embodiment 3

[0060] On the basis of Example 2, in order to further improve the stability of the preparation of phenyl polytrimethylsiloxane, and at the same time avoid the expanding gas pushing the reaction liquid to flow rapidly, resulting in the inability to accurately control the amount of reaction liquid added to the reaction bottle each time, and taking into account that under continuous heating, the gas in the reaction bottle and the constant pressure dropping funnel will gradually expand, which may easily cause the reaction bottle or the constant pressure dropping funnel to break under the action of air pressure, this embodiment further improves the constant pressure dropping component 30.

[0061] The constant pressure drip assembly 30 also includes a sealing assembly 38, which is arranged at the bottom of the sealing plug 37. The sealing assembly 38 includes a connecting disk 381, and the outer side of the connecting disk 381 is fixedly connected to the inner wall of the plug body 371. A through hole is opened in the middle of the upper end of the connecting disk 381, and a polygonal slide groove 382 is opened at the upper end of the connecting disk 381 and located on the outer side of the through hole. A plurality of slide rods 383 are movably connected in the polygonal slide groove 382, ​​and the number of the slide rods 383 is the same as the number of sides of the polygonal slide groove 382. A sealing member 384 is fixedly connected to the outer side of each slide rod 383, and the plurality of seals 384 are attached to each other and can seal the through hole. By designing the sealing assembly 38 at the bottom of the sealing plug 37, the connection strength of the sealing plug 37 is improved, thereby avoiding the sealing plug 37 from being deformed and losing its sealing ability under the action of a large amount of hot gas during the reaction process.

[0062] A driving disk 385 is provided above the sealing member 384, and the driving disk 385 is provided with limiting grooves 386 of the same number as the sliding rod 383. A plurality of ventilation pipes 387 are fixedly connected to the driving disk 385 in an annular array, and a plurality of connecting grooves 388 matching the ventilation pipes 387 are provided in an annular array on the connecting disk 381. An expansion member 389 is provided in each connecting groove 388, and the ventilation pipe 387 is slidably connected to the connecting groove 388 via the expansion member 389. The expansion of the expansion member 389 pushes the ventilation pipe 387 to slide in the connecting groove 388.

[0063] First, when the constant pressure drip assembly 30 is sealed and connected to the flask 40, the opening of the flask 40 is sealed by the sealing plug 37, so as to prevent the outside gas from entering the flask and affecting the reaction result during the reaction. At the same time, a sealing assembly 38 is arranged on the inner side of the bottom of the sealing plug 37, and a plurality of air outlet holes 372 are arranged on the sealing plug 37. The rigidity of the side of the sealing plug 37 is reduced by the arrangement of the plurality of air outlet holes 372. When the sealing plug 37 needs to be inserted into the flask 40, in order to improve the sealing effect, a diameter larger than the opening diameter of the flask 40 is usually selected. The sealing plug 37 is used to seal the flask 40. At this time, the inner wall of the flask 40 squeezes the sealing plug 37 to deform the sealing plug 37, so that the sealing plug 37 is tightly fitted with the flask 40. In this state, the side wall of the sealing plug 37 will be deformed and fit with the flask 40 due to the provision of multiple air outlet holes 372, and the bottom of the sealing plug 37 is limited by the deformation of the sealing plug 37 due to the provision of the sealing component 38, thereby avoiding the problem that in the subsequent heating process, the sealing component 38 is deformed due to heat, causing the inside of the flask 40 to contact with external gas and affect the preparation effect.

[0064] Secondly, when the solution in the flask 40 is heated to react, the gas in the flask 40 will absorb heat and expand. At this time, the expansion member 389 arranged in the connecting groove 388 will also absorb heat and expand. In this state, the expansion member 389 is heated to expand and push the ventilation pipe 387 to slide in the connecting groove 388. As the ventilation pipe 387 slides, the driving disk 385 connected to the ventilation pipe 387 will be synchronously driven to rotate. In this state, the rotating driving disk 385 will synchronously drive the multiple limit grooves 386 to rotate, so that the sliding rod connected to the limit grooves 386 383 slides in the polygonal slide groove 382, ​​so that the multiple seals 384 that fit each other move, thereby increasing the blocking range of the seal 384 on the through hole on the connecting plate 381 and reducing the aperture of the through hole. Since the top of the seal 384 fits with the liquid outlet of the dropper 34, the diameter of the liquid outlet of the dropper 34 is changed by the movement of the seal 384, and then the flow rate of the dropper 34 is restricted, so as to avoid the expanding gas pushing the reaction liquid to flow quickly, resulting in the problem that the amount of reaction liquid dripped into the reaction bottle each time cannot be accurately controlled, affecting the preparation accuracy.

[0065] It should be noted that Fig. 9 The state shown is that the expansion member 389 is fully expanded, so that the adjacent sides of the sealing member 384 are completely fitted and the through hole of the connecting plate 381 is completely blocked; Fig.10The state shown is that the expansion member 389 has not expanded under normal temperature and condition, and the adjacent sealing member 384 has opened the through hole; and the expansion member 389 can be a bellows structure, and a spring is arranged inside the bellows so that the bellows can reciprocately extend and contract, that is, when the air pressure inside the bellows is greater than the elastic force of the spring, the bellows extends under the action of the air pressure, and vice versa; at the same time, a pressure relief valve is provided at the connection between the expansion member 389 and the ventilation pipe 387. When the air pressure inside the expansion member 389 is greater than a preset value, the pressure relief valve opens to connect the expansion member 389 with the inside of the ventilation pipe 387.

[0066] Finally, as the oil bath heating device 10 continues to heat the flask 40, the temperature in the flask 40 will gradually increase, and the expansion of the gas therein will gradually increase with the increase in temperature. In order to prevent the flask 40 from being broken due to excessive pressure in the flask 40, the device continues to expand through the expansion member 389 when heated. When the gas in the expansion member 389 expands to the maximum state under the action of temperature, the expansion member 389 will first push the vent pipe 387 from one end of the connecting groove 388 to the other end during this process, so that the sealing member 384 completely blocks the through hole, preventing the solution in the cylinder 31 from moving into the flask 40 under the action of air pressure. At this time, due to the expansion member 389, the vent pipe 387 is pushed to move from one end of the connecting groove 388 to the other end. When the air pressure in the expansion piece 389 exceeds the preset value, the gas in the expansion piece 389 will be connected to the ventilation pipe 387 through the pressure relief valve. Since the ventilation pipe 387 moves to the other end of the connecting groove 388, the top of the ventilation pipe 387 will be connected to the air outlet 372, and the bottom of the ventilation pipe 387 will be connected to the inside of the flask 40, so that the gas in the flask 40 and the expansion piece 389 will be discharged to the outside through the ventilation pipe 387, reducing the air pressure value in the flask 40 and the expansion piece 389, thereby avoiding the problem that the gas in the flask 40 and the constant-pressure drip assembly 30 gradually expands, causing the flask 40 or the constant-pressure drip assembly 30 to break under the action of air pressure.

[0067] When the gas in the expansion piece 389 is discharged outward under the action of pressure, the force generated by the air pressure in the expansion piece 389 will be smaller than the elastic force of the spring. The elastic force of the spring will restore the expansion piece 389 to its initial state, and the connection between the dropper 34 and the flask 40 will be opened, so that the solution in the cylinder 31 can be dripped into the flask 40 normally, and the normal reaction will continue, thereby ensuring the stability of the production process.

[0068] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for preparing phenyl polytrimethylsiloxane, characterized in that: The following steps are involved: S1. Heating treatment: heating the flask (40) containing pure water using an oil bath heating device (10); S2. Dropping and mixing: using a temperature detection device to detect the temperature of the solution in the flask (40), when the temperature reaches a preset value, using a constant pressure drop assembly (30) to drop a mixture of trimethylchlorosilane and phenyltrichlorosilane into the flask (40); S3 hydrolysis reaction: The solution in the flask (40) is stirred and mixed, so that the solution in the flask (40) is hydrolyzed at a high temperature; S4. Oil-water separation: After the reaction of the solution in the flask (40) is completed, the flask (40) is allowed to stand and the lower aqueous phase is discharged; S5. Oil phase distillation: The oil phase in the flask (40) is added to the distillation reactor for distillation to obtain phenyl polytrimethylsiloxane; The constant pressure drip assembly (30) comprises a cylinder (31) provided with a liquid inlet and a liquid outlet, a connecting piece (32) fixedly connected to the liquid outlet at the bottom of the cylinder (31), a drip tube (34) fixedly connected to the bottom of the connecting piece (32), a constant pressure chamber (35) sheathed on the outside of the drip tube (34), a sealing plug (37) sheathed on the outside of the bottom of the constant pressure chamber (35), and a sealing assembly (38) provided at the bottom of the sealing plug (37); The sealing assembly (38) comprises a connecting plate (381), a through hole is formed in the middle of the upper end of the connecting plate (381), a polygonal slide groove (382) is formed at the upper end of the connecting plate (381) and located outside the through hole, a plurality of slide rods (383) are movably connected in the polygonal slide groove (382), a sealing member (384) is fixedly connected to the outer side of each slide rod (383), and the plurality of sealing members (384) are mutually attached and can seal the through hole; A driving disk (385) is provided above the sealing member (384), and a plurality of ventilation pipes (387) are fixedly connected to the driving disk (385) in an annular array, and a plurality of connecting grooves (388) adapted to the ventilation pipes (387) are provided in an annular array on the connecting disk (381), and an expansion member (389) is provided in each of the connecting grooves (388), and the ventilation pipe (387) is slidably connected to the connecting groove (388) via the expansion member (389), and the expansion of the expansion member (389) pushes the ventilation pipe (387) to slide in the connecting groove (388); When the solution in the flask (40) is heated and reacted, the gas in the flask (40) absorbs heat and expands. At this time, the expansion member (389) also absorbs heat and expands. The expansion member (389) pushes the vent pipe (387) to slide in the connecting groove (388) and drives the driving disk (385) connected to the vent pipe (387) to rotate. The driving disk (385) will synchronously drive the plurality of limit grooves (386) to rotate, so that the slide rod (387) 83) slides in the polygonal slide groove (382), thereby moving the multiple seals (384) that fit together, increasing the shielding range of the seals (384) on the through holes on the connecting plate (381), and reducing the diameter of the through holes. Since the top of the seal (384) fits together with the liquid outlet of the drip tube (34), the diameter of the liquid outlet of the drip tube (34) is changed by the movement of the seal (384), thereby limiting the flow rate of the drip tube (34).

2. The process for preparing phenyl polytrimethylsiloxane according to claim 1, characterized in that: The reaction time of the solution in the flask (40) in S3 is 1.5-3 hours.

3. The process for preparing phenyl trimethylsiloxane according to claim 1, characterized in that: After the reaction of the solution in the flask (40) in S4 is completed, the solution is allowed to stand for 50-70 minutes.

4. The process for preparing phenyl polytrimethylsiloxane according to claim 1, characterized in that: The oil bath heating device (10) is provided with a clamping assembly (20), and the clamping assembly (20) respectively clamps a constant pressure drip assembly (30) and a flask (40), and the flask (40) is located below the constant pressure drip assembly (30).

5. The process for preparing phenyl polytrimethylsiloxane according to claim 4, characterized in that: A connecting valve (33) is provided in the middle of the connecting piece (32), and the dripping tube (34) is connected to the interior of the cylinder (31) through the connecting piece (32). A connecting pipe (36) is fixedly connected to one side of the constant pressure chamber (35), and the constant pressure chamber (35) is connected to the cylinder (31) through the connecting pipe (36). The sealing plug (37) comprises a plug body (371), and a plurality of air outlet holes (372) are provided on the axial side of the plug body (371) in a circular array.

6. The process for preparing phenyl polytrimethylsiloxane according to claim 5, characterized in that: The outer side of the connecting plate (381) is fixedly connected to the inner wall of the plug body (371), and the number of the sliding rods (383) is the same as the number of sides of the polygonal sliding groove (382).

7. The process for preparing phenyl polytrimethylsiloxane according to claim 6, characterized in that: The driving disk (385) is provided with limiting grooves (386) having the same number as the sliding rods (383).

8. The process for preparing phenyl trimethylsiloxane according to claim 1, characterized in that: The oil bath heating device (10) further comprises a control console (11), a heating component (12) is provided above the control console (11), an oil bath pot (13) is provided in the middle of the heating component (12), and a detection component for detecting the water level of the heating liquid and a supply component for replenishing the heating liquid are provided in the oil bath pot (13).

9. The process for preparing phenyl trimethylsiloxane according to claim 4, characterized in that: The clamping assembly (20) further comprises a mounting seat (21), wherein the mounting seat (21) is fixed above the oil bath heating device (10), a mounting rod (22) is provided on the top of the mounting seat (21), a plurality of sliding seats (23) are slidably connected to the mounting rod (22), a locking screw (24) is provided on one side of each sliding seat (23), and the other end of each sliding seat (23) is rotatably connected to a rotating member (25), a connecting support rod (26) is provided on the rotating member (25), and a claw (27) is movably connected to the end of the connecting support rod (26) away from the rotating member (25).

10. The process for preparing phenyl polytrimethylsiloxane according to claim 9, characterized in that: The clamping claw (27) comprises two symmetrically arranged connecting arms (271), a plurality of threaded rods (272) for adjusting the spacing between the connecting arms (271) are arranged in a linear array between two adjacent connecting arms (271), one end of the connecting arm (271) movably connected to the connecting support rod (26) is provided with a limiting mechanism for limiting the rotation of the connecting arm (271), and one end of the connecting arm (271) away from the connecting support rod (26) is provided with a clamping piece (273).

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