Method for preparing Dawson heteropolyphosphatotungstate

A technology of phosphotungstoheteropolysalt and tungstate, which is applied in the direction of phosphorus oxyacid, can solve problems such as waste of raw materials, unresolved use problems, and equipment corrosion, so as to reduce equipment corrosion and reduce environmental pollution and safety hazards, yield and purity improvements

Inactive Publication Date: 2014-03-05
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method also has the problems of waste of raw materials and equipment corrosion in the acidification process of using excessive concentrated acid. At the same time, it uses flammable and explosive ether as the extraction agent, which has hidden safety and environmental risks.
At present, there are very few patent reports on the synthesis of Dawson type phosphotungstic heteropoly salt at home and abroad. CN1231943A discloses a synthesis method of Dawson type phosphotungstic heteropoly salt. , to obtain the product, avoiding ether extraction, but the problem of acidification with excess concentrated phosphoric acid has not been solved
EP1113877A1 and WO2007080067A1 have introduced methods for synthesizing Dawson-type phosphotungstic heteropoly salts. This method uses a small amount of concentrated phosphoric acid and a large amount of concentrated hydrochloric acid for acidification, refluxing and salting out, and finally extracts with ether to obtain the product. The use of strong acid acidification and ether is still a problem. did not get a good solution

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  • Method for preparing Dawson heteropolyphosphatotungstate
  • Method for preparing Dawson heteropolyphosphatotungstate

Examples

Experimental program
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Effect test

Embodiment 1

[0040] Weigh 30 grams of sodium tungstate dihydrate, add 50ml of deionized water, and stir until the sodium tungstate is completely dissolved; adjust the pH of the solution to 7.0 with 1mol / L hydrochloric acid; continue to adjust the solution to pH 1.0 with 1.5mol / L phosphoric acid After stirring for 1 hour, transfer to a 100ml autoclave with PTFE lining and heat at 100°C for 10 hours; after natural cooling, transfer the solution to a beaker, add potassium chloride to nearly saturation, and stir for 1 hour; Purify, filter and dry to constant weight to obtain 23.1 g of light yellow product, press K 6 [P 2 W 18 O 62 ]·14H 2 Based on O, the yield is about 94.3%. See the FT-IR spectrum of the product figure 1 , It can be seen that the product is at 1090cm -1 , 963cm -1 918cm -1 783cm -1 There is an obvious absorption peak, which is completely consistent with the FT-IR spectrum of the Dawson-type potassium phosphotungstate standard; 31 P-NMR nuclear magnetic resonance spectrum see f...

Embodiment 2

[0042] Weigh 30 grams of sodium tungstate dihydrate, add 25ml of deionized water, and stir until the sodium tungstate is completely dissolved; adjust the pH of the solution to 6.5 with 1mol / L hydrochloric acid; continue to adjust the solution to pH 1.0 with 5mol / L of phosphoric acid; After stirring for 1 hour, transfer to a 100ml autoclave with PTFE lining and heat at 120°C for 10 hours; after natural cooling, transfer the solution to a beaker, add potassium chloride to nearly saturation, and stir for 1 hour; purification , Filter and dry to constant weight to obtain 22.6 grams of light yellow product, press K 6 [P 2 W 18 O 62 ]·14H 2 Based on O, the yield is about 92.2%. The FT-IR spectrum of the sample phosphotungstic acid and 31 P-NMR nuclear magnetic resonance spectra are respectively figure 1 , figure 2 similar.

Embodiment 3

[0044] Weigh 30 grams of sodium tungstate dihydrate, add 50ml of deionized water, and stir until the sodium tungstate is completely dissolved; adjust the pH of the solution to 7.0 with 1mol / L hydrochloric acid; continue to adjust the solution to pH 0.5 with 10mol / L phosphoric acid; After stirring for 1 hour, transfer to a 100ml autoclave lined with polytetrafluoroethylene, and heat at 120°C for 4 hours; after natural cooling, transfer the solution to a beaker, add potassium chloride to nearly saturation, and stir for 1 hour; purification , Filter and dry to constant weight to obtain 21.9 grams of light yellow product, press K 6 [P 2 W 18 O 62 ]·14H 2 Based on O, the yield is about 89.4%. The FT-IR spectrum of the sample phosphotungstic acid and 31 P-NMR nuclear magnetic resonance spectra are respectively figure 1 , figure 2 similar.

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Abstract

The invention discloses a method for preparing Dawson heteropolyphosphatotungstate. The method comprises the following steps: (1) enabling a tungstate solution to come into contact with an inorganic acid solution, so as to obtain a reactive intermediate; (2) continuously enabling the solution to come into contact with a phosphoric acid solution, so as to obtain a phosphotungstic acid solution; (3) transferring the phosphotungstic acid solution to a high-pressure reactor, and carrying out high-temperature and high-pressure reaction; (4) adding an inorganic salt precipitant to the obtained phosphotungstic acid solution, carrying out salting-out crystallization to obtain phosphotungstate, filtering, purifying and drying, so as to obtain the Dawson heteropolyphosphatotungstate. Compared with the prior art, the method is simple in technological process, short in reaction cycle, high in yield and product purity, and low in cost; meanwhile, strong acid acidification and diethyl ether extraction used in the traditional method are avoided; the safety of the preparation process is greatly improved.

Description

Technical field [0001] The invention belongs to the technical field of heteropoly acid preparation, and specifically relates to a method for preparing high-purity Dawson-type phosphotungstate heteropoly acid. Background technique [0002] The general formula of Dawson-type phosphotungstic acid salt is: [0003] X 6 [Y 2 Z 18 O 62 ]·NH 2 O [0004] among them: [0005] X is the counter ion of Dawson type phosphotungstic heteropoly acid, such as H + , K + , Na + , NH 4 + Wait; [0006] Y represents a heteroatom or central atom, such as P, Si, Ge, etc.; [0007] Z represents polyatoms or coordination atoms, such as Mo, W, V, etc.; [0008] n is the number of crystal water, generally a positive integer from 0 to 30. [0009] Dawson-type phosphotungstic heteropoly compound is one of the most typical structures in heteropoly acid, with P as heteroatom, W as coordinating atom, P and W atomic ratio 2:18, with Dawson space structure. Due to its unique structure and properties, Dawson-type tungste...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/16
Inventor 李洁陈启元高鑫
Owner CENT SOUTH UNIV
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