Method for continuous preparation of polysiloxane by fixed-bed reactor

A fixed bed reactor and polysiloxane technology, applied in the field of organic silicon materials, can solve the problems of reduced catalytic performance, damage of ion exchange resin, etc., and achieve the effects of low reaction temperature, high mechanical strength, and avoidance of residual impurities

Active Publication Date: 2016-06-29
JIANGSU MAYSTA CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

During the reaction, the ion exchange resin is easily damaged due to

Method used

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  • Method for continuous preparation of polysiloxane by fixed-bed reactor

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Experimental program
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Effect test

Embodiment 1

[0025] Add 50.0 grams of zirconium hydroxide and 77.6 grams of ammonium paramolybdate into 200 ml of distilled water and mix evenly, stir at 80°C for 12 hours, dry at 105°C, press into tablets at 10MPa, and sieve 40-60 mesh particles , baked at 800°C for 3 hours. Take 50.0 grams of particles and immerse in 40 milliliters of boric acid aqueous solution with a concentration of 5.0 mg boron / ml for 12 hours, dry at 105°C, and roast at 400°C for 3 hours to obtain boron-modified B 2 o 3 -MoO 3 / ZrO 2 A solid acid catalyst, wherein the molar ratio of elements is B:Mo:Zr=0.28:1:5.

[0026] The reactor used is a tubular fixed bed with a length of 40 cm and an inner diameter of 20 mm. Put 50 grams of the above-mentioned solid acid catalyst into the middle section of the reaction tube, according to the mass ratio HS:D 4 : MM=0.41:6.56:1 Put the raw materials into the pre-mixer and mix them evenly, and preheat to 40°C. The mass space velocity is 40h -1 , after the product flows thr...

Embodiment 2

[0029] Add 100.0 grams of zirconium hydroxide and 77.6 grams of ammonium paramolybdate into 200 ml of distilled water and mix evenly, stir at 80°C for 12 hours, dry at 105°C, press into tablets at 10MPa, and sieve 40-60 mesh particles , Baked at 800°C for 3 hours, cooled and taken out. Get 50.0 grams of granules and soak in 40 milliliters of boric acid aqueous solution with a concentration of 5.0 mg boron / ml for 12 hours, dry at 105°C, and roast at 400°C for 3 hours to obtain B 2 o 3 -MoO 3 / ZrO 2 The catalyst, wherein the molar ratio of elements is B:Mo:Zr=0.51:1:10.

[0030] The preparation conditions of polysiloxane were the same as in Example 1. Target product MD for one-way reaction 7 D, 3 M yield was 38%.

[0031] Pass the mixture of low boiling matter and bottom liquor into the reactor again to prepare the target product MD 7 D, 3 M, calculate the target product MD after reaction 7 D, 3 M overall yield was 81%.

Embodiment 3

[0033] Add 100.0 grams of zirconium hydroxide and 51.7 grams of ammonium paramolybdate into 200 ml of distilled water and mix evenly, stir at 80°C for 12 hours, dry at 105°C, press into tablets at 10MPa, and sieve 40-60 mesh particles , Baked at 800°C for 3 hours, cooled and taken out. Get 50.0 grams of granules and soak in 40 milliliters of boric acid aqueous solution with a concentration of 5.0 mg boron / ml for 12 hours, dry at 105°C, and roast at 400°C for 3 hours to obtain B 2 o 3 -MoO 3 / ZrO 2 The catalyst, wherein the molar ratio of elements is B:Mo:Zr=0.74:1:15.

[0034]The preparation conditions of polysiloxane were the same as in Example 1. The target product yield for a single pass reaction was 36%.

[0035] Pass the mixture of low boiling matter and bottom liquor into the reactor again to prepare the target product MD 7 D, 3 M, calculate the target product MD after reaction 7 D, 3 M overall yield was 76%.

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Abstract

The invention belongs to the technical field of organic silicon materials and relates to a method for continuous preparation of polysiloxane by a fixed-bed reactor. The method includes: taking B2O3-MoO3/ZrO2 solid super acid as a catalyst and taking polymethylhydrosiloxane (HS), octamethylcyclotetrasiloxane (D4) and hexamethyldisiloxane (MM) as raw materials, well mixing the raw materials in a premixer and heating to a certain temperature, continuously feeding raw material mixed liquor through the upper end of the fixed-bed reactor to realize reaction, delivering filtered products into a distiller, removing low-boiling-point substances, evaporating a target product out, and feeding mixed liquid of the low-boiling-point substances and kettle residual liquor into the reactor to prepare the target product. The method is low in reaction temperature, raw material utilization rate and target product yield are high, operation process is simple and easy to realize continuous production, the solid acid is low in corrosion effect on equipment and destructive effect on environment, and energy saving and environment friendliness are realized.

Description

technical field [0001] The invention relates to a method for continuously preparing polysiloxane in a fixed-bed reactor, belonging to the technical field of organic silicon materials. Background technique [0002] Low molecular weight polysiloxane has stable chemical properties, low surface tension, excellent lubricity and heat and acid resistance. Based on the above excellent physical and chemical properties, polysiloxane has good properties in polyurethane foam, daily chemical products, construction and textiles. application prospects. At present, domestic enterprises mainly use stirred reactors to produce various polysiloxanes, H 2 SO 4 、CF 3 SO 3 H, KOH and (CH 3 ) 4 NOH is a traditional catalyst. This type of catalyst is highly corrosive. After the reaction, it must go through processes such as neutralization, water washing, filtration or heating to decompose the catalyst to obtain the final product. The production efficiency and raw material utilization rate of t...

Claims

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Application Information

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IPC IPC(8): C08G77/08C08G77/12
CPCC08G77/08C08G77/12
Inventor 孙宇李丰富何运伟尹迎阳
Owner JIANGSU MAYSTA CHEM
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