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Process for preparing calcium magnesium acetate by vacuum distillation method

A technology of calcium magnesium acetate and distillation method, which is applied in the preparation of carboxylate, organic chemistry, etc., can solve the problems of large volatilization loss of acetic acid, decrease of product purity, high temperature requirements, etc., and achieve product purity improvement, simple dehydration, and reaction The effect of low temperature

Inactive Publication Date: 2002-11-13
TSINGHUA UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main defect of the above process has two points, the one, because the granulation drying equipment is complicated, the temperature requirement in the whole reaction process is very high (not lower than 90 ℃), causes the volatilization loss of acetic acid to be bigger, causes product purity to decline; The amount of water required in the reaction process must be continuously adjusted as the fluid enters the drying equipment for granulation and drying. The flow rate and drying effect are constantly adjusted, resulting in high energy consumption in the dehydration process

Method used

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  • Process for preparing calcium magnesium acetate by vacuum distillation method
  • Process for preparing calcium magnesium acetate by vacuum distillation method

Examples

Experimental program
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Effect test

Embodiment 1

[0013] Take 500ml of deionized water at room temperature, slowly add 2.878mol of glacial acetic acid, then add 0.483mol of CaO and 1.100mol of MgO at one time, and stir to make it react for 1.5hr, the solution is slightly yellow, and the reaction temperature is 45±5℃. Adjust the pH value with a calcium-magnesium mixture with a molar ratio of Ca:Mg=3:7 until the solution shows weak alkaline pH=7.4, centrifuge and filter to separate excess calcium and magnesium oxide after resting. The pH of the mother liquor was measured to be 9.11.

[0014] Put the mother liquor into a rotary evaporator and carry out vacuum distillation at a pressure of -0.096 to -0.098MPa and a temperature of 50±5°C. After vacuum distillation for 1.5 hours, a large amount of white crystals precipitated, and the volume of the distillate was measured. The distillate was measured by high pressure liquid chromatography, and the concentration of acetate ion was 2.475×10 -3 mol / L, pH=4.60, the loss rate of acetic ...

Embodiment 2

[0016] Take 500ml of deionized water at room temperature, slowly add 4.029mol of glacial acetic acid, then add 0.672mol of CaO and 1.34mol of MgO at one time, and stir to make it react for 2 hours. The solution is slightly yellow, and the reaction temperature is 70±5℃. The calcium and magnesium mixture with a molar ratio of Ca:Mg=3:6 is used to adjust the pH value until the solution shows a weakly alkaline pH=8.5. After resting, centrifuge and filter to separate excess calcium and magnesium oxide. The pH of the mother liquor was measured to be 9.56.

[0017] Put the mother liquor into a rotary evaporator and carry out vacuum distillation at a pressure of -0.095 to -0.098 MPa and a temperature of 75±5°C. After 3.5 hours of vacuum distillation, a large amount of white crystals precipitated, and the volume of the distillate was measured. The distillate was measured by high pressure liquid chromatography, and the concentration of acetate ion was 3.755×10 -3 mol / L, pH=4.16, the lo...

Embodiment 3

[0019] Take 500ml of deionized water at room temperature, add 0.483mol of CaO and 1.100mol of MgO to form a mixed emulsion of calcium oxide and magnesium oxide, slowly add 2.878mol of glacial acetic acid, and stir to make it happen. Control the temperature at 85±5 Between ℃, the required time of complete reaction is about 3 hours, and the obtained mother liquor is similar to Example 1.

[0020] Put the mother liquor into a rotary evaporator and carry out vacuum distillation. The control pressure is -0.083~-0.086Mpa, and the other conditions are the same. The required temperature for vacuum distillation is 85±5°C and the required time is 5hr. The concentration of acetate ion in the distillate is 6.635×10 -3 mol / L, pH=3.62, acetic acid loss rate is 0.015%.

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Abstract

A process for preparing calcium magnesium acetate includes such steps as mixing Ca and Mg compound (the mole ratio of Ca:Mg is 3-4:6-7) with solution of acetic acid, to form a solution with concentration of (3-5) mol / L, reaction at 40-90 deg.C for 1-3 hr, filtering, vacuum distilling concentration at 45-90 deg.C and under -0.08-0.1 MPa for 1-5 hr, and drying. Its advantages are simple process, low reaction temp. and high purity of product.

Description

technical field [0001] The invention relates to a method for preparing calcium magnesium acetate salt by vacuum distillation, which belongs to the technical field of fine chemical preparation. Background technique [0002] Calcium Magnesium Acetate (CMA) is a calcium-magnesium acetate compound salt, a new environmentally friendly chemical developed in the United States in the early 1980s to replace highway deicing agents (sodium chloride). CMA has good water solubility, low melting point, and biodegradability. Compared with sodium chloride, it can reduce the corrosion of concrete and metal by chloride ions in vehicles and road infrastructure and the pollution of surface water. Studies in recent years have also found that CMA has the ability to remove NO produced by coal combustion. x , SO 2 And the HCl produced by PVC combustion to control air pollution. U.S. Patents US4699725 and US4913831 respectively reported the use of X-ray diffraction and "TGA-GC-MSD" (differential ...

Claims

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Application Information

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IPC IPC(8): C07C51/41C07C53/10
Inventor 秦炜赵音延戴猷元
Owner TSINGHUA UNIV
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