Catalyst used for alcoholysis of urea for synthesizing propylene carbonate and preparation and application methods thereof

A propylene carbonate and catalyst technology, applied in chemical instruments and methods, physical/chemical process catalysts, organic chemistry, etc., can solve the problems of poor catalyst stability, low catalytic activity, and complicated preparation, and achieve simple preparation and high catalytic activity. , the effect of simple process

Inactive Publication Date: 2011-02-23
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Looking at the existing catalysts for the synthesis of PC by alcoholysis of urea, there are mainly the following problems: (1) catalyst stability is poor, separation is difficult, and preparation is more loaded down with trivial details
(2) The catalytic acti

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Catalyst preparation: at room temperature, a mixed solution of 150ml zinc nitrate (0.1mol / L) and lead nitrate (0.05mol / L), and excess sodium carbonate solution (0.2mol / L) were slowly added dropwise to 500ml in a three-necked flask with constant vigorous stirring. During the dropwise addition, control the rate of addition of sodium carbonate to keep the precipitation pH constant at about 8.0. After the dropwise addition, continue to stir for 30 minutes, then filter with suction and wash repeatedly with distilled water until there is no Na+, and then dry at 110°C for 12 hours to obtain the Pb-Zn mixed carbonate catalyst.

[0015] Synthesis of PC: Add 24.0 g of urea, 45.60 g of 1,2-propanediol and 0.635 g of catalyst into a four-neck round bottom flask. Under stirring, the four-necked flask was placed in an oil bath and reacted at 180°C for 4h. During the reaction process, nitrogen gas was continuously fed into the reaction solution to take away the ammonia gas produced ...

Embodiment 2

[0017] Catalyst preparation: at room temperature, a mixed solution of 150ml lead nitrate (0.1mol / L) and chromium nitrate (0.033mol / L) and excess sodium carbonate solution (0.1mol / L) were slowly added dropwise to 500ml in a three-necked flask with constant vigorous stirring. During the dropwise addition, the rate of addition of sodium carbonate was controlled to keep the precipitation pH value constant at about 9.0. After the dropwise addition, continue to stir for 60 minutes, then filter with suction and wash repeatedly with distilled water until there is no Na+, and then dry at 90°C for 12 hours to obtain the Pb-Cr mixed carbonate catalyst.

[0018] Synthesis of PC: Add 6.0 g of urea, 22.80 g of 1,2-propanediol and 0.518 g of catalyst into a four-neck round bottom flask. Under stirring, the four-necked flask was placed in an oil bath and reacted at 170°C for 6h. During the reaction process, nitrogen gas was continuously fed into the reaction solution to take away the ammoni...

Embodiment 3

[0020] Catalyst preparation: at room temperature, a mixed solution of 200ml magnesium nitrate (0.3mol / L) and chromium nitrate (0.2mol / L), and excess sodium carbonate solution (0.3mol / L) were slowly added dropwise to 500ml in a three-necked flask with constant vigorous stirring. During the dropping process, the dropping rate of sodium carbonate was controlled to keep the precipitation pH value constant at about 10.0. After the dropwise addition, continue to stir for 30 minutes, then filter with suction and wash repeatedly with distilled water until there is no Na+, and then dry at 100°C for 12 hours to obtain the Mg-Cr mixed carbonate catalyst.

[0021] Synthesis of PC: Add 27.36 g of urea, 58.94 g of 1,2-propanediol and 3.452 g of catalyst into a four-neck round bottom flask. Under stirring, the four-necked flask was placed in an oil bath and reacted at 160°C for 5h. During the reaction process, nitrogen gas was continuously fed into the reaction solution to take away the am...

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PUM

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Abstract

The invention discloses a catalyst used for alcoholysis of urea for synthesizing propylene carbonate and preparation and application methods thereof. The catalyst consists of mixed metal carbonate of Pb-Zn, Pb-Mg, Pb-Cr, Zn-Mg, Zn-Cr or Mg-Cr, and is prepared by performing coprecipitation reaction on corresponding metal nitrate mixed solution and excessive sodium carbonate solution. The application method of the catalyst is that: the reaction pressure is the natural pressure, the reaction temperature is between 140 and 180 DEG C, the reaction time is 2 to 8 h, a molar ratio of a reactant urea and 1,2-propylene glycol is 1:1-1:20, and the adding amount of the catalyst is 0.5 to 6 weight percent. The catalyst has the advantages of high catalytic activity, low cost, long service life, simple process in the application process, environmental friendliness, mild reaction condition, small using amount of the 1,2-propylene glycol, high yield of the propylene carbonate and cheap and readily available raw materials, is easy to prepare and reaction can be performed at normal temperature and the like.

Description

technical field [0001] The invention relates to a urea alcoholysis catalyst and its application, in particular to a mixed metal carbonate catalyst for synthesizing propylene carbonate by urea alcoholysis and its application. Background technique [0002] Propylene carbonate (PC) belongs to cyclic carbonate, is a high boiling point and high polarity organic solvent and fine chemical synthesis intermediate with excellent performance, widely used in petrochemical, electrochemical and textile printing and dyeing industries. At the same time, it is also the raw material for the production of dimethyl carbonate by transesterification. Compared with the traditional process, the synthesis of PC by alcoholysis of urea and 1,2-propanediol has the advantages of mild reaction conditions, environmental friendliness, safe operation, safe raw materials and low cost. The ammonia gas generated by the reaction can be recycled to the urea production unit to improve the utilization rate of raw...

Claims

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Application Information

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IPC IPC(8): C07D317/36B01J27/232
Inventor 吴东方张碧蓉郭亚莉周建成
Owner SOUTHEAST UNIV
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