Catalyst for preparing dimethyl carbonate and method for preparing dimethyl carbonate

A technology of dimethyl carbonate and propylene carbonate, which is applied in the field of catalysts for the preparation of dimethyl carbonate, can solve the problems of difficult precise control of the time of propylene glycol stripping, environmental pollution, and reduction of propylene glycol yield, so as to increase the yield of dimethyl carbonate. The overall technical level of the ester industry, the effect of solving key technical problems and reducing the pressure of environmental protection

Active Publication Date: 2020-07-31
SHANDONG DEPU CHEM IND SCI & TECH
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  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0004] 1. The methanol solution of sodium methoxide is used as a catalyst in the production of dimethyl carbonate by transesterification. The core is that sodium methoxide plays a catalytic role. The process is mature and the conversion rate is high. The disadvantage is that the dosage is large, and the proportion of ingredients is propylene carbon: methanol: sodium methoxide = 100:126:7
The amount of sodium methoxide is large, accounting for a high production cost
[0005] 2. In the transesterification reaction between propylene carbonate and methanol to generate dimethyl carbonate, it is difficult to separate the propylene glycol and sodium methoxide catalyst in the reaction product system
Because sodium methoxide is strongly alkaline, it is not only easy to corrode equipment, but also causes propylene glycol and catalysts to easily form viscous aggregates. At the same time, a large number of high polymers such as dipropylene glycol and tripropylene glycol are produced by side reactions, which gradually accumulate in the production device system. In order to ensure the normal operation of the production unit, it must be discharged regularly, reducing the yield of propylene glycol and easily causing environmental pollution
[0006] 3. The propylene glycol recovery system adopts vacuum intermittent rectification or continuous rectification process. During the rectification process, it is difficult to accurately control the propylene glycol stripping period. 2% polypropylene glycol high boilers are entrained in propylene glycol, which makes the product quality difficult to stabilize. Affect the color of the product; at the same time, the water in the system causes the sodium methoxide catalyst to form sodium carbonate solid and deposit, which affects the normal operation of the equipment
[0007] 4. The process is long, the investment is large, the equipment is huge, and the occupied area is large

Method used

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  • Catalyst for preparing dimethyl carbonate and method for preparing dimethyl carbonate
  • Catalyst for preparing dimethyl carbonate and method for preparing dimethyl carbonate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Embodiment 1 prepares dimethyl carbonate

[0033] A device for preparing dimethyl carbonate, comprising a tubular methanol vaporizer (with a heat exchange area of ​​10㎡), a propylene carbonate preheater (with a heat exchange area of ​​10㎡), a tubular reactor (with a diameter of 2 meters, 6 meters high, tube diameter 32 mm) and flash tank, such as figure 1 As shown, wherein, the tubular methanol vaporizer is connected to the top of the tubular reactor; the top of the tubular reactor is provided with a mist distributor, and the propylene carbonate preheater is communicated with the tubular reactor through the mist distributor ; The bottom of the tube-and-tube reactor communicates with the flash tank.

[0034] Using the above-mentioned device to prepare dimethyl carbonate: feed methanol into the tubular methanol vaporizer, heat, control the pressure at 0.2Mpa, and the vaporized methanol enters the tubular reactor. Heat the propylene carbonate preheater to raise the tempe...

Embodiment 2

[0037] Embodiment 2 prepares dimethyl carbonate

[0038] Pass methanol to the tubular methanol vaporizer, heat up, control the pressure at 0.2Mpa, and the vaporized methanol enters the tubular reactor. Heat the propylene carbonate preheater to raise the temperature of the propylene carbonate to 110-120°C, and enter the tube-and-tube reactor through the mist distributor. The shell-and-tube reactor is filled with a catalyst, and reacts at a temperature of 115° C. and a pressure of 0.2 MPa. A sample was taken from the bottom of the reactor for analysis, and the content of propylene carbonate was 0.2%. The prepared dimethyl carbonate enters the flash tank from the bottom of the reactor for purification (the gas enters the gas phase methanol and dimethyl ester to remove the separation system, and the liquid phase enters the propylene glycol to remove the purification system). After calculation, the dimethyl carbonate yield 99.7%.

[0039] The mass ratio of methanol and propylene...

Embodiment 3

[0041] Embodiment 3 prepares dimethyl carbonate

[0042] Pass methanol to the tubular methanol vaporizer, heat up, control the pressure at 0.2Mpa, and the vaporized methanol enters the tubular reactor. Heat the propylene carbonate preheater to raise the temperature of the propylene carbonate to 110-120°C, and enter the tube-and-tube reactor through the mist distributor. The shell-and-tube reactor is filled with a catalyst and reacted at a temperature of 110° C. and a pressure of 0.2 MPa. A sample was taken from the bottom of the reactor for analysis, and the content of propylene carbonate was 0.1%. The prepared dimethyl carbonate enters the flash tank from the bottom of the reactor for purification (the gas enters the gas phase methanol and dimethyl ester to remove the separation system, and the liquid phase enters the propylene glycol to remove the purification system). After calculation, the dimethyl carbonate yield 99.8%.

[0043] The mass ratio of methanol and propylene...

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Abstract

The invention discloses a catalyst for preparing dimethyl carbonate. Porous spherical activated aluminium oxide is used as a carrier on which potassium carbonate and sodium carbonate are loaded, wherein 200-300 g of the potassium carbonate and 80-130 g of the sodium carbonate are contained per 1000 g of the catalyst. The invention further discloses a method for preparing the dimethyl carbonate. The method comprises the following steps: using vaporized methanol of which the pressure is 0.2 Mpa, and vaporous propylene carbonate of which the temperature is 110-120 DEG C; and under the conditionsof the action of the catalyst, 110+(-)10 DEG C of the temperature and 0.2 Mpa of the pressure, preparing the dimethyl carbonate. The method for preparing the dimethyl carbonate has the characteristicsof moderate reaction condition, low reaction pressure (0.2 Mpa), low reaction temperature (110 DEG C), high propylene carbonate conversion percent (99.9%), and high product yield (99.8%). It is forecasted that after the industrialization is realized, the cost is greatly saved, and environmental protection pressure is relieved.

Description

technical field [0001] The invention relates to a catalyst for preparing dimethyl carbonate and a method for preparing dimethyl carbonate. Background technique [0002] Dimethyl carbonate has a variety of reactivity characteristics and a variety of excellent performance characteristics, and is widely used in coatings, food, medicine, fuel additives, energy and other fields. According to incomplete statistics, dimethyl carbonate, as the source material of fine chemical synthesis, has accounted for 12.7% of the entire organic fine chemical industry. Dimethyl carbonate is an environmentally friendly green raw material. It has passed the registration of non-toxic chemicals in Europe. It is called "green chemical" and is recognized as the "new cornerstone" of green organic synthesis. At the same time, it can also be used as a green additive for other products. Because it is a "green chemical" product and meets the requirements of the sustainable development strategy, all countr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J27/232B01J37/02B01J37/08C07C68/065C07C69/96
CPCB01J27/232B01J37/0201B01J37/08C07C68/065C07C69/96
Inventor 卢伟张淑娟王安华刘长峰卢建行陈爱民
Owner SHANDONG DEPU CHEM IND SCI & TECH
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