CN113387978B - Method for preparing diphenyl dimethoxysilane by continuous alcoholysis method - Google Patents
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- 238000006136 alcoholysis reaction Methods 0.000 title claims abstract description 200
- AHUXYBVKTIBBJW-UHFFFAOYSA-N dimethoxy(diphenyl)silane Chemical compound C=1C=CC=CC=1[Si](OC)(OC)C1=CC=CC=C1 AHUXYBVKTIBBJW-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 title claims abstract description 65
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 580
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 80
- 239000000047 product Substances 0.000 claims abstract description 65
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims abstract description 62
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims abstract description 62
- 238000006243 chemical reaction Methods 0.000 claims abstract description 54
- OSXYHAQZDCICNX-UHFFFAOYSA-N dichloro(diphenyl)silane Chemical compound C=1C=CC=CC=1[Si](Cl)(Cl)C1=CC=CC=C1 OSXYHAQZDCICNX-UHFFFAOYSA-N 0.000 claims abstract description 48
- 238000005406 washing Methods 0.000 claims abstract description 39
- 239000012043 crude product Substances 0.000 claims abstract description 37
- 239000000460 chlorine Substances 0.000 claims abstract description 22
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 21
- 238000010992 reflux Methods 0.000 claims abstract description 11
- 230000008016 vaporization Effects 0.000 claims description 108
- 238000009834 vaporization Methods 0.000 claims description 101
- 238000010521 absorption reaction Methods 0.000 claims description 24
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- 239000012467 final product Substances 0.000 claims 1
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- 230000001276 controlling effect Effects 0.000 description 34
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- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 29
- 238000003860 storage Methods 0.000 description 29
- 238000010438 heat treatment Methods 0.000 description 14
- 238000007086 side reaction Methods 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 239000012535 impurity Substances 0.000 description 10
- 238000001514 detection method Methods 0.000 description 9
- 239000006227 byproduct Substances 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 7
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- WQDUMFSSJAZKTM-UHFFFAOYSA-N Sodium methoxide Chemical compound [Na+].[O-]C WQDUMFSSJAZKTM-UHFFFAOYSA-N 0.000 description 2
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- CZBRNBNJNICTKD-UHFFFAOYSA-N benzhydryloxy(chloro)silane Chemical compound C1(=CC=CC=C1)C(O[SiH2]Cl)C1=CC=CC=C1 CZBRNBNJNICTKD-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/18—Compounds having one or more C—Si linkages as well as one or more C—O—Si linkages
- C07F7/1804—Compounds having Si-O-C linkages
- C07F7/1872—Preparation; Treatments not provided for in C07F7/20
- C07F7/188—Preparation; Treatments not provided for in C07F7/20 by reactions involving the formation of Si-O linkages
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/20—Purification, separation
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- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
Abstract
The invention provides a method for preparing diphenyldimethoxysilane by a continuous alcoholysis method, which comprises the following steps: (1) methanol is vaporized; (2) continuous alcoholysis: the vaporized methanol and the diphenyl dichlorosilane continuously enter an alcoholysis tower, and the methanol and the diphenyl dichlorosilane are subjected to alcoholysis reaction in a counter-current manner; (3) refluxing methanol; (4) absorbing hydrogen chloride; (5) washing a crude product: washing the crude product with methanol; and (6) collecting the finished product. The methanol is vaporized to form a reactant with a heat source, and the reactant and the diphenyldichlorosilane are subjected to alcoholysis reaction, so that the reaction rate is improved, the crude product is washed by the methanol to dissolve free chlorine, and the methanol is recycled and vaporized to enter an alcoholysis tower to participate in the reaction as a raw material to form a continuous alcoholysis process. The rectification device is reduced, an acid binding agent is avoided, the production cost and the equipment energy consumption are reduced, the waste is reduced, and the method is suitable for industrial production.
Description
Technical Field
The invention belongs to the field of organic silicon production, and particularly relates to a method for preparing diphenyl dimethoxysilane by a continuous alcoholysis method.
Background
Diphenyl dimethoxysilane is an important organosilicon compound used for producing phenyl silicone oil, phenyl silicone resin, phenyl silicone rubber and the like, and also used as a cocatalyst for adjusting polypropylene in propylene polymerization.
The traditional synthesis method of the diphenyldimethoxysilane comprises a one-step method and a two-step method. The one-step method is to put two raw materials of diphenyl dichlorosilane and excessive methanol into a reactor at one time, and directly obtain a target product without taking out an intermediate. The two-step method is that diphenyl dichlorosilane and methanol are firstly subjected to equimolar reaction to obtain intermediate diphenyl methoxychlorosilane, and then the intermediate is subjected to reaction with the methanol to obtain the target product diphenyl dimethoxysilane. The hydrogen chloride gas generated by the two methods is removed by adding a large amount of acid absorbent or purging with inert gas, and the product quality is poor and the yield is low due to the complex process.
Van Min et al in the synthesis and application of diphenyldimethoxysilane (Populus oil chemical, 1997) to improve the two-step process, in the connection with a hydrogen chloride absorber, equimolar diphenyldichlorosilane and methanol reaction, then four times of reaction and delamination, get the diphenyldimethoxysilane. The generated hydrogen chloride is absorbed by the hydrogen chloride absorber to achieve the effect of reducing the occurrence of side reactions, but the method is only suitable for laboratory pilot scale tests, has complex process and is not suitable for industrial large-scale production.
Chenqing and the like in synthesis and application of diphenyldimethoxysilane (Zhejiang chemical industry, 1997) adopt a solvent with a boiling range of 60-90 ℃ to heat and boil the solvent to form a reflux and fully wet filler. Methanol and diphenyldichlorosilane are respectively added dropwise. Meanwhile, dry nitrogen is introduced into the three-neck flask, so that the byproduct hydrogen chloride gas is discharged out of the system through condensation by the rising air flow and the low-boiling-point steam and enters an absorption device. And cooling, taking out the material, neutralizing the material by using sodium methoxide to a pH value of 7-8 under stirring and cooling conditions, and rectifying to obtain the diphenyldimethoxysilane. The reaction solution is heated by a solvent to accelerate the separation speed of hydrogen chloride, so that the aim of reducing the occurrence of side reaction is fulfilled.
CN109021007 adopts diphenyldichlorosilane to dissolve in organic solvent, then alcohol-alkoxide solution is added, reaction is carried out under inert atmosphere, after part of reaction is carried out, alkoxide solution is added, reaction is continued, and after the reaction is finished, diphenyl dimethoxysilane is obtained by rectification. The method adopts alkoxide as an acid-binding agent to generate hydrogen chloride to form chloride salt.
CN109796488 has designed a special tower reactor, this tower reactor is heated by 3 heating sections, diphenyl dichlorosilane and methyl alcohol adopt the countercurrent mode to enter the tower reactor, the hydrogen chloride gas that produces after the esterification is discharged by tower top of the tower reactor, the crude product of diphenyl dimethoxysilane obtains target product diphenyl dimethoxysilane through neutralization rectification after discharging from tower reactor bottom, need further rectification after the esterification, need through complicated physics and chemical process, lead to equipment inefficiency and consume energy greatly, the local concentration of separation element is too high, cause rectification column equipment pipe blockage, corruption equipment and pipeline easily, the design requirement to the esterification column is higher.
The hydrogen chloride gas generated by the reaction of the diphenyldichlorosilane and the alcohol is easy to generate side reaction with other reactants, so how to quickly escape the generated hydrogen chloride from the reaction system is the key point for improving the yield of the diphenyldimethoxysilane. However, the existing preparation methods are complicated, some methods need to add acid-binding agents, catalysts and other auxiliaries, and some methods need to remove HCl by a solvent method or an acid absorption method. Due to the influence of byproducts, the existing reaction system mostly adopts a single or a plurality of reactors for separating products, the products are separated by rectification or distillation after alcoholysis reaction, and complex physical and chemical processes are needed, so that the equipment efficiency is low, the energy consumption is high, the production cost is high, the solvent recovery is difficult, and the large-scale industrial production is not suitable.
Disclosure of Invention
The invention provides a method for preparing diphenyl dimethoxysilane by a continuous alcoholysis method, which comprises the following steps:
(1) methanol vaporization: the methanol is vaporized by a vaporization tower.
Controlling the temperature in the vaporization tower to be 60-70 ℃, taking methanol as a gas phase reactant and having a heat source, and carrying out alcoholysis reaction with the diphenyldichlorosilane.
Preferably, staged vaporization is used.
The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is controlled to be 40-55 ℃, the first vaporization area is used for primarily heating the recovered methanol, removing other impurities, and saving energy consumption; and controlling the temperature of the second gasification zone to be 60-70 ℃ to obtain a methanol heat source reactant suitable for reaction, and feeding the methanol heat source reactant into the alcoholysis tower to participate in the alcoholysis reaction.
Or the vaporization tower is divided into three vaporization areas, the temperature of the first vaporization area is controlled to be 40-50 ℃, the temperature of the second vaporization area is controlled to be 51-60 ℃, and the temperature of the third vaporization area is controlled to be 61-70 ℃. The turbulence degree of molecular turbulence is further improved, the chemical reaction speed of the main reaction is higher than the diffusion/mass transfer speed, and the main reaction speed is improved; meanwhile, the chemical reaction speed of the side reaction is lower than the diffusion/mass transfer speed, the side reaction speed is reduced, the by-product hydrogen chloride is less, and the by-product hydrogen chloride can overflow quickly and be absorbed.
The vaporization tower enables methanol to form vaporization gradient and temperature difference through segmented temperature control, the methanol recovered by washing is effectively utilized, volatile impurities (such as free chlorine and the like) are removed through primary heating, and then the temperature is further raised to form reactants with heat sources, so that the energy consumption is greatly reduced.
(2) Continuous alcoholysis: the diphenyl dichlorosilane continuously enters an alcoholysis tower with a vacuum control system, the reaction temperature at the top of the alcoholysis tower is 50-70 ℃, and the reaction temperature at the bottom of the alcoholysis tower is 110-140 ℃; controlling the vacuum system at 50-100 mmHg; preferably, the reaction temperature at the top of the tower is controlled to be 50-66 ℃, and the reaction temperature at the bottom of the tower is controlled to be 120-130 ℃; the vacuum system was controlled at 60-70 mm Hg.
Methanol from the vaporization tower enters the alcoholysis tower as a reactant and heat source provider, and by regulating the vacuum degree and temperature of the alcoholysis tower, the methanol has gaseous and liquid balance at the same time and reacts with the diphenyldichlorosilane in a countercurrent mode, so that the reaction efficiency is high, and as the forward reaction progress rate is increased, the byproduct hydrogen chloride can be rapidly discharged under the conditions of heating and vacuum and is absorbed by an absorption device. The final diphenyldimethoxysilane has high yield and purity.
The alcoholysis tower is an enamel packed tower, and the packing is ceramic ring stacked or regular ceramic packing.
Controlling the feeding speed by a feeding valve, wherein the molar ratio of the diphenyl dichlorosilane to the methanol is 1: 2-2.5, preferably 1: 2-2.1.
The reaction temperature at the top and bottom of the alcoholysis tower is adjusted by a reboiler at the bottom of the alcoholysis tower or outside the alcoholysis tower.
The reboiler is selected from one or more of thermosyphon type, forced circulation type, kettle type reboiler and built-in reboiler.
The alcoholysis tower is provided with a vacuum control system, so that the pressure of the system can be adjusted, and the overflow and absorption of the hydrogen chloride gas at the top of the tower are facilitated.
The synthesis of the diphenyldimethoxysilane comprises the following chemical reactions:
(C6H5)2SiCl2+2CH3OH＝(C6H5)2Si(OCH3)2+HCl
but side reactions may occur in the middle:
(C6H5)2SiCl2+CH3OH＝(C6H5)2Si(OCH3)Cl+HCl
the methanol is in a gas-liquid coexisting equilibrium state after being vaporized in sections, so that the methanol is more active, the reaction rate is improved, a vaporization gradient is provided, the methanol raw material contains a plurality of temperature gradients and sources, the alcoholysis reaction is facilitated, the forward and reverse reactions are accelerated, the hydrogen chloride can be quickly discharged in an upward floating mode along with the methanol gas, and the possibility of side reactions is reduced. And acid methanol (namely methanol with a small amount of HCl dissolved) is formed by washing, so that the acid methanol is easy to separate, and the water vapor is prevented from entering to reduce the generation of byproducts.
Meanwhile, the content of HCl as a byproduct in the crude product obtained by the method is low (lower than 100ppm), so that the product can be separated only by simple alcohol washing and sedimentation, and complicated normal-temperature or high-temperature distillation and rectification processes are omitted.
The invention can avoid adding catalyst, acid-binding agent, other solvent, inert gas and other substances by adjusting the technological parameters of the methanol raw material such as feeding mode, reaction condition and the like, fully utilizing the property of the circulating material and matching with the rough vacuum reaction condition in the alcoholysis tower, thereby ensuring the product yield, greatly reducing the cost and simplifying the technological process for industrialized scale.
(3) Methanol refluxing: excessive methanol escaping from the top of the alcoholysis tower is cooled and collected, and then returns to the alcoholysis tower to participate in the alcoholysis reaction.
The methanol at the top of the tower is cooled to 30-50 ℃ by a cooler.
The collection can be performed by a methanol receiving tank, a methanol collecting tank, or the like.
At the moment, the collected methanol is in a liquid state, and flows back to the alcoholysis tower to further participate in the alcoholysis reaction process, so that the reactant efficiency is improved.
(4) Absorption of hydrogen chloride: the top of the alcoholysis tower is provided with a hydrogen chloride absorption device, so that the hydrogen chloride generated by alcoholysis reaction passes through the hydrogen chloride absorption device and is absorbed by water to prepare hydrochloric acid with the concentration of 22-31 wt%.
The hydrogen chloride rapidly escapes from the reaction device under the heating state and the vacuum condition, and hydrochloric acid is formed through water absorption, so that the side reaction is reduced. The hydrogen chloride absorption device is a falling film absorber or a water jet vacuum pump, and the falling film absorber is preferred.
(5) Washing a crude product: and (3) cooling and recovering the diphenyl dimethoxysilane which is a bottom product of the alcoholysis tower to obtain a crude diphenyl dimethoxysilane product, washing the crude diphenyl dimethoxysilane product with methanol to remove a small amount of free chlorine, and recovering the methanol and feeding the methanol into a methanol vaporization tower to vaporize again.
The washing comprises one or more of stirring, loop, countercurrent and the like; the amount of washing methanol used was 20 to 30wt% based on the crude diphenyldimethoxysilane.
Washing the crude product, dissolving a small amount of free chlorine in methanol, wherein the washed methanol contains a small amount of hydrogen chloride, the hydrogen chloride has certain solubility in the methanol, and the content of the hydrogen chloride in the washed methanol is lower than 100ppm, so that the crude product can enter a vaporization tower again.
After methanol enters the methanol vaporization tower to be vaporized, the alcoholysis tower is used as a reaction raw material to participate in alcoholysis reaction, a circulating system of washing recovery and continuous alcoholysis is formed, and the efficiency of the reaction raw material is improved. The continuous alcoholysis circulation is uninterrupted by a reactant recovery multi-circulation system, and the method is suitable for industrial application.
(6) Collecting a finished product: washing with alcohol, settling and collecting the finished product of the diphenyl dimethoxy silane.
And washing the crude product with methanol to remove free chlorine, and settling for 3-6h in a layering kettle to obtain a finished product of the diphenyl dimethoxysilane.
The invention also provides a device for preparing the diphenyldimethoxysilane by the continuous alcoholysis method, which comprises a methanol vaporization tower, an alcoholysis tower, a reboiler, a cooler, an alcohol receiving tank, a crude product condenser, a crude product receiving tank, a washing kettle, a layering kettle, an alcohol storage tank and a finished product storage tank.
Wherein the methanol vaporization tower is connected with the alcoholysis tower (1), the top of the alcoholysis tower is provided with a cooler (3) and an alcohol receiving tank (4), the bottom of the alcoholysis tower is provided with a crude product condenser (5) and a crude product receiving tank (6), and the bottom or the outside of the alcoholysis tower is provided with a reboiler (2); the outlet of the alcohol receiving tank (4) is connected with the alcoholysis tower (1); the outlet of the crude product receiving tank (3) is connected with a washing kettle (7), and the washing kettle is provided with a methanol inlet; the washing kettle (7) is connected with the layering kettle (8), after sedimentation and layering, the bottom of the layering kettle (8) is connected with a finished product storage tank (10), and the top of the layering kettle is connected with an alcohol storage tank (9).
The top of the alcoholysis tower (1) is also provided with a hydrogen chloride absorption device, preferably a falling film absorber, which is used for preparing hydrochloric acid with the concentration of 22-31 wt%.
The reboiler is selected from one or more of thermosyphon type, forced circulation type, kettle type reboiler and built-in reboiler.
The alcoholysis tower is an enamel packed tower, and the packing is ceramic ring stacked or regular ceramic packing.
The invention has the beneficial effects that:
1. the method utilizes the reaction of the vaporized methanol and the diphenyl dichlorosilane, the hydrogen chloride rapidly escapes from the reaction device under the heating state and the vacuum condition, and hydrochloric acid is formed by water absorption, so that side reaction products are reduced, and the yield and the product quality are improved.
2. According to the invention, by adopting the method of washing the crude product of the diphenyldimethoxysilane by using the methanol, the free chlorine of the diphenyldimethoxysilane is dissolved in the methanol, and the washed methanol enters the alcoholysis tower through vaporization and is used as a raw material with a heat source to participate in the reaction and react with the diphenyldichlorosilane for alcoholysis reaction, so that the reaction rate is improved, the subsequent separation difficulty is reduced, the distillation or rectification step is avoided, the process flow is greatly simplified, and the production cost is reduced.
3. The invention only adjusts the continuous alcoholysis process, the washing process and the methanol vaporization process, so that the preparation process of the diphenyldimethoxysilane becomes easier, the raw materials are fully utilized to optimize the reaction process, the hydrogen chloride overflow is reduced, the process flow is simplified, the equipment investment is reduced, the industrialized mass production is realized, and the treatment capacity can reach more than ten thousand tons.
4. The continuous alcoholysis process has mild reaction conditions, does not add other separation additives such as acid-binding agents, catalysts, alkoxides and the like, reduces the generation of waste materials, reduces the corrosion of equipment, reduces the side effect caused by the contact of the additives, avoids complicated separation steps, reduces the cost, is suitable for industrial production, has high product yield and less side reaction, and ensures that the yield of the product, namely the diphenyldimethoxysilane reaches more than 93 percent and the content of free chlorine is less than 35 ppm.
5. The invention adopts methanol vaporization, methanol recovery at the top of the tower and methanol recovery by alcohol washing as raw materials, the methanol vaporization is carried out in a segmented way, and the vacuum degree and the bottom temperature in the alcoholysis tower are regulated and controlled, so that the reactant methanol has gas-liquid balance, and the invention not only has the characteristic of self-carried heat source of a gas temperature ladder, but also utilizes the characteristic of high dynamic reaction efficiency of gas-liquid methanol, and carries out reaction under proper conditions in the alcoholysis tower, thereby promoting the alcoholysis reaction to be carried out, reducing byproducts and effectively removing other impurities; meanwhile, multiple cycles of an alcohol washing recycling system realize continuous alcoholysis reaction, so that the utilization rate and the conversion rate of raw materials are fully improved, and the energy consumption is reduced.
Drawings
FIG. 1 is a flowchart of the operation of example 1 of the present invention.
Wherein, the device comprises a 1-alcoholysis tower, a 2-reboiler, a 3-cooler, a 4-alcohol receiving tank, a 5-crude product condenser, a 6-crude product receiving tank, a 7-washing kettle, an 8-layering kettle, a 9-alcohol storage tank and a 10-finished product storage tank.
Detailed Description
The technical solution of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention. The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.
Example 1
A method for preparing diphenyldimethoxysilane by a continuous alcoholysis method specifically comprises the following steps:
(1) methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol which is taken as a reactant and has a heat source enters the alcoholysis tower to carry out alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is 55 ℃ for primary heating of recovered methanol, and the temperature of the second vaporization area is 70 ℃, so that a methanol heat source suitable for reaction is obtained, other impurities can be effectively removed, and energy consumption can be saved.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding gas-phase methanol according to a feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to a feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 66 ℃ and controlling the vacuum system to be 60 mm Hg, and carrying out alcoholysis reaction on reactant diphenyldichlorosilane and vaporized methanol.
(3) Methanol refluxing: collecting methanol collected at the top of the tower through a cooler 3 and an alcohol collector 4, then connecting the methanol to an alcoholysis tower 1, observing that the alcoholysis tower 1 reaches a certain liquid level after an alcohol receiving tank 4 of the alcoholysis tower reaches a certain liquid level, cooling a bottom product, namely a diphenyl dimethoxysilane crude product to 50 ℃ through a cooler 5, and transferring the bottom product to a crude product receiving storage tank 6. And (5) maintaining the stability of the system and making operation records.
Wherein, the liquid level ensures the retention time of the alcoholysis liquid, and the retention time is 2 hours according to the entering materials, namely the volume of 160 kilograms (liters).
(4) Absorption of hydrogen chloride: the hydrogen chloride generated by the alcoholysis reaction enters a hydrogen chloride absorption device and is absorbed by water to form dilute hydrochloric acid with the concentration of about 23 wt%.
(5) A washing system: adding 700kg of diphenyldimethoxysilane in the crude product receiving storage tank into a washing kettle 7, adding 200kg of liquid methanol, stirring for 3h, transferring the liquid into a layering kettle 8, layering after settling for 4h, feeding the methanol containing hydrogen chloride at the upper layer into an alcohol storage tank 9, feeding the methanol into a methanol vaporization tower, vaporizing the methanol, feeding the vaporized methanol into an alcoholysis tower 1, and continuing to participate in alcoholysis reaction.
(6) Collecting finished products: the lower layer of the layering kettle 8 is a finished product of diphenyl dimethoxysilane which enters a finished product storage tank 10. The detection proves that the yield of the finished product of the diphenyldimethoxysilane is 98.1 percent, the purity is 98.7 percent, and the content of free chlorine is less than 5 ppm.
Example 2
A method for preparing diphenyldimethoxysilane by a continuous alcoholysis method specifically comprises the following steps:
(1) methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol is used as a reactant and has a heat source, and enters the alcoholysis tower to perform alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is 55 ℃ and is used for primary heating of recovered methanol, the temperature of the second vaporization area is 70 ℃, a methanol heat source suitable for reaction is obtained, other impurities can be effectively removed, and energy consumption can be saved.
(2) Continuous alcoholysis: opening the alcoholysis tower 1 to feed methanol, adding vaporized methanol according to the feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to the feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 120 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 55 ℃, controlling a vacuum system to be 70 mm Hg, and carrying out alcoholysis reaction on the reactant diphenyldichlorosilane and the vaporized methanol.
(3) Methanol refluxing: collecting methanol collected at the top of the tower through a cooler 3 and an alcohol collector 4, then connecting the methanol to an alcoholysis tower 1, observing that the alcoholysis tower 1 reaches a certain liquid level (160 kg volume) after an alcohol receiving tank 4 of the alcoholysis tower reaches a certain liquid level, cooling a product diphenyl dimethoxysilane crude product at the bottom of the tower to 50 ℃ through a cooler 5, and transferring the product diphenyl dimethoxysilane crude product to a crude product receiving storage tank 6. And (5) maintaining the stability of the system and making operation records.
(4) Absorption of hydrogen chloride: the hydrogen chloride generated by alcoholysis reaction enters a hydrogen chloride absorption device and is absorbed by water to be diluted hydrochloric acid.
(5) A washing system: adding 700kg of diphenyldimethoxysilane in the crude product receiving storage tank into a washing kettle 7, adding 200kg of liquid methanol, stirring for 3 hours, transferring the liquid into a layering kettle 8, layering after settling for 4 hours, feeding the methanol containing hydrogen chloride at the upper layer into an alcohol storage tank 9, feeding into a methanol vaporization tower, feeding into an alcoholysis tower 1 after vaporization, and continuing to participate in the alcoholysis reaction.
(6) Collecting finished products: the lower layer of the layering kettle 8 is a finished product of diphenyl dimethoxysilane which enters a finished product storage tank 10. The detection proves that the yield of the finished product of the diphenyldimethoxysilane is 97.8 percent, the purity is 98.2 percent, and the content of free chlorine is less than 10 ppm.
Example 3
A method for preparing diphenyldimethoxysilane by a continuous alcoholysis method specifically comprises the following steps:
(1) methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol is used as a reactant and has a heat source, and enters the alcoholysis tower to perform alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is 55 ℃ and is used for primary heating of recovered methanol, the temperature of the second vaporization area is 70 ℃, a methanol heat source suitable for reaction is obtained, other impurities can be effectively removed, and energy consumption can be saved.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding vaporized methanol according to a feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to 80 kg/h when the temperature at the top of the alcoholysis tower 1 is 50 ℃, adjusting the vacuum degree, controlling the bottom temperature of the alcoholysis tower to be 140 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 60 ℃, controlling the vacuum system to be 68 mm Hg, and carrying out alcoholysis reaction on reactant diphenyldichlorosilane and the vaporized methanol.
(3) Methanol refluxing: collecting methanol collected at the top of the tower through a cooler 3 and an alcohol collector 4, then connecting the methanol to an alcoholysis tower 1, observing that the alcoholysis tower 1 reaches a certain liquid level after an alcohol receiving tank 4 of the alcoholysis tower reaches a certain liquid level (160 kg volume), cooling a bottom product, namely a diphenyl dimethoxysilane crude product to 50 ℃ through a cooler 5, and transferring the bottom product to a crude product receiving storage tank 6. And (5) maintaining the stability of the system and making operation records.
(4) Absorption of hydrogen chloride: the hydrogen chloride generated by alcoholysis reaction enters a hydrogen chloride absorption device and is absorbed into dilute hydrochloric acid by water.
(5) A washing system: adding 700kg of diphenyldimethoxysilane in the crude product receiving storage tank into a washing kettle 7, adding 200kg of liquid methanol, stirring for 3h, transferring the liquid into a layering kettle 8, layering after settling for 4h, feeding the methanol containing hydrogen chloride on the upper layer into an alcohol storage tank 9, then feeding the methanol into a methanol vaporization tower, vaporizing the methanol, feeding the vaporized methanol into an alcoholysis tower 1, and continuing to participate in alcoholysis reaction.
(6) Collecting finished products: the lower layer of the layering kettle 8 is a finished product of diphenyl dimethoxysilane which enters a finished product storage tank 10. The detection proves that the yield of the finished product of the diphenyldimethoxysilane is 97.0 percent, the purity is 97.9 percent, and the content of free chlorine is 15 ppm.
Example 4
A method for preparing diphenyldimethoxysilane by a continuous alcoholysis method specifically comprises the following steps:
(1) methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol is used as a reactant and has a heat source, and enters the alcoholysis tower to perform alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into three areas, wherein the temperature of the first vaporization area is 45 ℃, the temperature of the second vaporization area is 58 ℃, and the temperature of the third vaporization area is 70 ℃.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding vaporized methanol according to the feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to the feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 66 ℃, controlling the vacuum system to be 60 mm Hg, and carrying out alcoholysis reaction on the reactant diphenyldichlorosilane and the methanol.
(3) Methanol refluxing: collecting methanol collected at the top of the tower through a cooler 3 and an alcohol collector 4, then connecting the methanol to an alcoholysis tower 1, observing that the alcoholysis tower 1 reaches a certain liquid level (160 kg volume) after an alcohol receiving tank 4 of the alcoholysis tower reaches a certain liquid level, cooling a bottom product, namely a diphenyl dimethoxysilane crude product to 50 ℃ through a cooler 5, and transferring the bottom product to a crude product receiving storage tank 6. And (5) maintaining the stability of the system and making operation records.
(4) Absorption of hydrogen chloride: the hydrogen chloride generated by alcoholysis reaction enters a hydrogen chloride absorption device and is absorbed by water to be diluted hydrochloric acid.
(5) A washing system: adding 700kg of diphenyldimethoxysilane in the crude product receiving storage tank into a washing kettle 7, adding 200kg of liquid methanol, stirring for 3h, transferring the liquid into a layering kettle 8, layering after settling for 4h, feeding the methanol containing hydrogen chloride on the upper layer into an alcohol storage tank 9, then feeding the methanol into a methanol vaporization tower, vaporizing the methanol, feeding the vaporized methanol into an alcoholysis tower 1, and continuing to participate in alcoholysis reaction.
(6) Collecting finished products: the lower layer of the layering kettle 8 is a finished product of diphenyl dimethoxysilane which enters a finished product storage tank 10. The detection proves that the yield of the finished product of the diphenyldimethoxysilane is 98.7 percent, the purity is 98.8 percent, and the content of free chlorine is less than 5 ppm.
Example 5
A method for preparing diphenyldimethoxysilane by a continuous alcoholysis method specifically comprises the following steps:
(1) methanol vaporization: after being vaporized by a vaporization tower, the methanol is used as a reactant and also has a heat source, and enters an alcoholysis tower, wherein the temperature in the vaporization tower is 70 ℃.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding vaporized methanol according to the feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to the feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 66 ℃, controlling the vacuum system to be 60 mm Hg, and carrying out alcoholysis reaction on the reactant diphenyldichlorosilane and the methanol.
(3) Methanol refluxing: collecting methanol collected at the top of the tower through a cooler 3 and an alcohol collector 4, then connecting the methanol to an alcoholysis tower 1, observing that the alcoholysis tower 1 reaches a certain liquid level (160 kg volume) after an alcohol receiving tank 4 of the alcoholysis tower reaches a certain liquid level, cooling a bottom product, namely a diphenyl dimethoxysilane crude product to 50 ℃ through a cooler 5, and transferring the bottom product to a crude product receiving storage tank 6. And (5) maintaining the stability of the system and making operation records.
(4) Absorption of hydrogen chloride: the hydrogen chloride generated by alcoholysis reaction enters a hydrogen chloride absorption device and is absorbed by water to be diluted hydrochloric acid.
(5) A washing system: adding 700kg of diphenyldimethoxysilane in the crude product receiving storage tank into a washing kettle 7, adding 200kg of liquid methanol, stirring for 3h, transferring the liquid into a layering kettle 8, layering after settling for 4h, feeding the methanol containing hydrogen chloride on the upper layer into an alcohol storage tank 9, then feeding the methanol into a methanol vaporization tower, vaporizing the methanol, feeding the vaporized methanol into an alcoholysis tower 1, and continuing to participate in alcoholysis reaction.
(6) Collecting finished products: the lower layer of the layering kettle 8 is a finished product of diphenyl dimethoxysilane which enters a finished product storage tank 10. The detection proves that the yield of the finished product of the diphenyldimethoxysilane is 95.5 percent, the purity is 96.9 percent, and the content of free chlorine is 29 ppm.
Example 6
(1) Methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol is used as a reactant and has a heat source, and enters the alcoholysis tower to perform alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is 55 ℃ and is used for primary heating of recovered methanol, the temperature of the second vaporization area is 70 ℃, a methanol heat source suitable for reaction is obtained, other impurities can be effectively removed, and energy consumption can be saved.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding gas-phase methanol according to a feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to a feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 50 ℃ and controlling the vacuum system to be 60 mm Hg, and carrying out alcoholysis reaction on reactant diphenyldichlorosilane and methanol.
The other steps are the same as example 1, and the yield of the finished product of the diphenyldimethoxysilane is 93.0 percent, the purity is 97.3 percent and the content of free chlorine is about 33 ppm.
Example 7
(1) Methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol is used as a reactant and has a heat source, and enters the alcoholysis tower to perform alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is 55 ℃ and is used for primary heating of recovered methanol, the temperature of the second vaporization area is 70 ℃, a methanol heat source suitable for reaction is obtained, other impurities can be effectively removed, and energy consumption can be saved.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding gas-phase methanol according to a feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to a feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 70 ℃ and controlling the vacuum system to be 60 mm Hg, and carrying out alcoholysis reaction on reactant diphenyldichlorosilane and vaporized methanol.
The other steps are the same as the example 1, and the detection shows that the yield of the finished product of the diphenyldimethoxysilane is 94.2 percent, the purity is 97.4 percent, and the content of free chlorine is 32 ppm.
Example 8
(1) Methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol is used as a reactant and has a heat source, and enters the alcoholysis tower to perform alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is 55 ℃ and is used for primary heating of recovered methanol, the temperature of the second vaporization area is 70 ℃, a methanol heat source suitable for reaction is obtained, other impurities can be effectively removed, and energy consumption can be saved.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding gas-phase methanol according to a feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to a feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 66 ℃ and controlling the vacuum system to be 50 mm Hg, and carrying out alcoholysis reaction on reactant diphenyldichlorosilane and vaporized methanol.
The other steps are the same as the example 1, and the detection shows that the yield of the finished product of the diphenyldimethoxysilane is 95.1 percent, the purity is 95.7 percent, and the content of free chlorine is 35 ppm.
Example 9
(1) Methanol vaporization: after being vaporized by stages in the vaporization tower, the methanol is used as a reactant and has a heat source, and enters the alcoholysis tower to perform alcoholysis reaction with the diphenyldichlorosilane. The vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is 55 ℃ and is used for primary heating of recovered methanol, the temperature of the second vaporization area is 70 ℃, a methanol heat source suitable for reaction is obtained, other impurities can be effectively removed, and energy consumption can be saved.
(2) Continuous alcoholysis: checking the vacuum degree of the system, opening a methanol feeding amount of an alcoholysis tower 1, adding gas-phase methanol according to a feeding amount of 20.5 kg/h, adding diphenyldichlorosilane into the alcoholysis tower according to a feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 66 ℃ and controlling the vacuum system to be 100 mm Hg, and carrying out alcoholysis reaction on reactant diphenyldichlorosilane and vaporized methanol.
The other steps are the same as the example 1, and the detection shows that the yield of the finished product of the diphenyldimethoxysilane is 96.2 percent, the purity is 95.9 percent, and the content of free chlorine is 35 ppm.
Comparative example 1
A method for preparing diphenyldimethoxysilane comprises the following steps:
(1) alcoholysis: opening the liquid-phase methanol feeding at the lower part of the alcoholysis tower 1, adding the liquid-phase methanol according to the feeding amount of 20.5 kg/h, adding the diphenyldichlorosilane into the alcoholysis tower according to the feeding amount of 80 kg/h, controlling the bottom temperature of the alcoholysis tower to be 130 ℃ through the opening of a valve of a reboiler 2, controlling the top temperature of the alcoholysis tower to be 66 ℃, controlling the vacuum system to be 60 mm Hg, and carrying out alcoholysis reaction on the reactant diphenyldichlorosilane and the methanol.
(2) Methanol refluxing: collecting methanol collected at the top of the tower through a cooler 3 and an alcohol collector 4, then connecting the methanol to an alcoholysis tower 1, observing that the alcoholysis tower 1 reaches a certain liquid level (160 kg volume) after an alcohol receiving tank 4 of the alcoholysis tower reaches a certain liquid level, cooling a bottom product, namely a diphenyl dimethoxysilane crude product to 50 ℃ through a cooler 5, and transferring the bottom product to a crude product receiving storage tank 6. And (5) maintaining the stability of the system and making operation records.
(3) Absorption of hydrogen chloride: the hydrogen chloride generated by the alcoholysis reaction enters a hydrogen chloride absorption device and is absorbed by water to form dilute hydrochloric acid with the concentration of about 23 wt%.
(4) A washing system: adding 700kg of diphenyldimethoxysilane into a washing kettle 7, adding 200kg of liquid methanol, stirring for 3h, transferring the liquid into a layering kettle 8, layering after settling for 4h, introducing the methanol containing hydrogen chloride at the upper layer into an alcohol storage tank 9, introducing into a methanol vaporization tower, vaporizing, introducing into an alcoholysis tower 1, and continuing to participate in alcoholysis reaction.
(5) Collecting finished products: the lower layer of the layering kettle 8 is a finished product of diphenyl dimethoxysilane which enters a finished product storage tank 10. The detection proves that the yield of the finished product of the diphenyldimethoxysilane is 91.2 percent, the purity is 88.9 percent, and the content of free chlorine is about 300 ppm. See table 1 for example and comparative example data.
TABLE 1
It can be seen that the invention can effectively reduce the occurrence of hydrogen chloride side reactions by vaporizing the methanol reactant in advance, forming a vaporization gradient with a heat source by utilizing the sectional heating, then carrying out alcoholysis reaction, and utilizing the methanol reflux at the top of the tower, collecting the hydrogen chloride and absorbing the hydrogen chloride into hydrochloric acid; meanwhile, the method utilizes simple alcohol washing and precipitation processes to separate free chlorine in the diphenyldimethoxysilane, recovers the washing methanol, and circularly enters the vaporization and alcoholysis processes to form a circular process flow of continuous alcoholysis.
The yield of the diphenyldimethoxysilane prepared by the continuous alcoholysis method of the invention reaches more than 93 percent, and the content of free chlorine is less than 35 ppm; particularly, the reaction temperature at the top of the alcoholysis tower is 55-66 ℃, and the reaction temperature at the bottom of the alcoholysis tower is 120-130 ℃; under the condition of 60-70 mm Hg of a vacuum system, the gas-liquid equilibrium state is more easily formed by segmented vaporization and circulating methanol, so that the alcoholysis reaction rate and the reaction kinetics are optimized, the yield of the product, namely the diphenyldimethoxysilane, reaches more than 97 percent, and the content of free chlorine is less than 20 ppm. The methanol vaporized in the single section can have gas-liquid equilibrium under the proper conditions of the alcoholysis tower, but the turbulence degree of the raw material is slightly low, so the product yield is slightly reduced.
It will be understood by those skilled in the art that the foregoing embodiments are merely for clarity of description and are not intended to limit the scope of the invention. Other variations or modifications will occur to those skilled in the art based on the foregoing disclosure and are within the scope of the invention.
Claims (8)
1. A method for preparing diphenyl dimethoxy silane by a continuous alcoholysis method is characterized by comprising the following steps:
(1) methanol vaporization: vaporizing the methanol by a vaporization tower, wherein the temperature in the vaporization tower is 60-70 ℃; the method comprises the following steps that (1) sectional vaporization is adopted, the vaporization tower is divided into two vaporization areas, the temperature of the first vaporization area is controlled to be 40-55 ℃, and the temperature of the second vaporization area is controlled to be 60-70 ℃; or the vaporization tower is divided into three vaporization areas, the temperature of the first vaporization area is controlled to be 40-50 ℃, the temperature of the second vaporization area is controlled to be 51-60 ℃, and the temperature of the third vaporization area is controlled to be 61-70 ℃;
(2) continuous alcoholysis: the vaporized methanol and the diphenyl dichlorosilane continuously enter an alcoholysis tower, and the methanol and the diphenyl dichlorosilane perform alcoholysis reaction in a countercurrent manner, wherein the reaction temperature at the top of the alcoholysis tower is 55-66 ℃, and the reaction temperature at the bottom of the alcoholysis tower is 120-130 ℃; controlling the vacuum system at 60-70 mm Hg;
(3) methanol refluxing: cooling and collecting methanol escaped from the top of the alcoholysis tower, and returning the methanol to the alcoholysis tower to participate in alcoholysis reaction;
(4) absorbing hydrogen chloride;
(5) washing a crude product: washing the crude product of the diphenyl dimethoxysilane by using methanol to remove a small amount of free chlorine, and recovering the methanol to enter a vaporization tower;
(6) and collecting a finished product.
2. The process of claim 1, wherein the molar ratio of diphenyldichlorosilane to methanol is 1: 2-2.5.
3. The process of claim 1, wherein the molar ratio of diphenyldichlorosilane to methanol is 1: 2-2.1.
4. The method of claim 1 or 3, wherein the alcoholysis tower is an enameled packed tower, and the packing is ceramic ring packing or structured ceramic packing; the temperature of the alcoholysis tower is adjusted by a reboiler at the bottom of the alcoholysis tower or outside the alcoholysis tower.
5. The method of claim 1, wherein the methanol at the top of the column is cooled to 30-50 ℃ by a cooler in the step (3).
6. The process of claim 1, wherein the top of the alcoholysis tower is provided with a hydrogen chloride absorption unit to make 22-31wt% hydrochloric acid.
7. The process of claim 1, wherein the amount of washing methanol is 20-30wt% of the crude diphenyldimethoxysilane.
8. The method as claimed in claim 7, wherein the alcohol-washed product is settled for 3-6h to obtain the final product of diphenyl dimethoxy silane.
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