Preparation method of sodium phosphate dibasic dodecahydrate

A technology of disodium hydrogen phosphate dodecahydrate and phosphoric acid, which is applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of energy consumption, and achieve the effects of low equipment requirements, high impurity removal rate, and easy control

Inactive Publication Date: 2014-06-04
TIANJIN KERMEL CHEM REAGENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the temperature is high, refrigeration equipment must be used to keep the crystallizatio

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Weigh 40g of sodium hydroxide in 400ml of deionized water to dissolve into a clear solution; while stirring, slowly add 57.5g of phosphoric acid solution with a concentration of 85% by mass to the solution, adjust the pH of the solution to 8.2; keep the temperature at 60 ℃, continue to stir the solution for 15 minutes; measure the pH value of the solution without significant change, filter; the filtrate is cooled to 30 ℃ under stirring, and crystals are precipitated; continue to cool to 20 ℃, and the precipitated crystals and mother liquor are separated by suction and filtration; the crystals are dispersed. Place in a dish and air dry at room temperature for 1 hour. The content of disodium hydrogen phosphate dodecahydrate in the test final product was 98.49%, the pH value was 9.11, and the product yield was 90%.

Embodiment 2

[0030] Weigh 200g of sodium hydroxide in 2000ml of deionized water to dissolve into a clear solution; while stirring, slowly add 287.5g of phosphoric acid solution with a concentration of 85% by mass to the solution, adjust the pH of the solution to 8.3; keep the temperature at 63 ℃, continue to stir the solution for 18 minutes; measure the pH value of the solution without obvious change, filter; the filtrate is cooled to 32℃ under stirring, and crystals are precipitated; continue to cool to 20℃, and the precipitated crystals and mother liquor are separated by suction and filtration; the crystals are dispersed. Place in a dish and air-dry at room temperature (15~25℃) for 3 hours. The content of disodium hydrogen phosphate dodecahydrate in the test final product was 98.37%.

Embodiment 3

[0032] Weigh 160g of sodium hydroxide in 800ml of deionized water to dissolve into a clear solution; while stirring, slowly add 230g of phosphoric acid solution with a concentration of 85% by mass to the solution, adjust the pH of the solution to 8.4; keep the temperature at 66℃ , Continue to stir the solution for 25 minutes; measure the pH value of the solution without significant change, filter; the filtrate is cooled to 35°C under stirring, and crystals are precipitated; continue to cool to 20°C, and the precipitated crystals and mother liquor are separated by suction and filtration; In a dish, air dry at room temperature for 2 hours. The content of disodium hydrogen phosphate dodecahydrate in the test final product was 99.2%, the pH value was 9.2, and the product yield was 75%.

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PUM

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Abstract

The invention discloses a preparation method of sodium phosphate dibasic dodecahydrate, and the preparation method of the sodium phosphate dibasic dodecahydrate comprises the following steps: according to the weight ratio, weighing 1 part of sodium hydroxide to put into 3.125-10 parts of deionized water to dissolve into a clear solution; under stirring, adding 1.4375 parts of a phosphoric acid solution with a concentration of 85% by mass into the clear solution, adjusting the pH of the solution to 8.2-8.6; keeping the temperature to be 60-70 DEG C, continuing stirring the solution for 15-25min; measuring the solution pH, until the solution pH has no obvious changes, filtering; cooling a filtrate under stirring to 30-35 DEG C, precipitating for crystallization; continuing cooling to 20 DEG C, filtering by suction to separate a precipitated crystal and a mother liquid; and putting the crystal flat and scatteredly in a dish, and drying in air for 1-3h at room temperature. The preparation method of the sodium phosphate dibasic dodecahydrate has the advantages of short technological process, low requirement on equipment, stable and mild process conditions, easiness in control, no need for heating, condensation and proportion adjusting, crystallization at the room temperature, and suitability for industrialized production.

Description

Technical field [0001] The invention relates to the field of chemical synthesis, in particular to a preparation method of disodium hydrogen phosphate dodecahydrate. Background technique [0002] Disodium hydrogen phosphate (Na 2 HPO 4 ) Six products of monohydrate, dihydrate, heptahydrate, octahydrate and dodecahydrate are crystallized from the solution at different temperatures. Usually only three products of heptahydrate, twelve water and anhydrous are produced. Disodium hydrogen phosphate dodecahydrate (Na 2 HPO 4 ·12H 2 O) is a colorless monoclinic crystal with a relative density of 1.52, soluble in water, and a 1% aqueous solution with a pH of 8.8. The precipitation temperature of disodium hydrogen phosphate dodecahydrate in the solution is 0~35℃, and disodium hydrogen phosphate heptahydrate (Na 2 HPO 4 ·7H 2 O), dihydrate and disodium hydrogen phosphate (Na 2 HPO 4 ·2H 2 O) Anhydrous disodium hydrogen phosphate can be obtained above 95℃, and anhydrous material is easy to a...

Claims

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Application Information

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IPC IPC(8): C01B25/30
Inventor 李刚苏学松陈曙林立成秦汉超
Owner TIANJIN KERMEL CHEM REAGENT
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