Preparation method of toothpaste-grade tin chloride

A stannous chloride, toothpaste-grade technology, applied in the field of preparation of toothpaste-grade stannous chloride, can solve the problems of low product purity, long synthesis process time, difficult use, etc., and achieve stable process, low cost, and less three wastes Effect

Active Publication Date: 2014-01-29
RES INST OF PHYSICAL & CHEM ENG OF NUCLEAR IND
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

In this method, chlorine gas belongs to Class 2.3 poisonous and dangerous goods, which is difficult to use, and the synthesis process takes a long time. The highly toxic barium chloride is used as the anti-purifying agent for removing heavy metals. kg, cannot be used as a toothpaste additive

Method used

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  • Preparation method of toothpaste-grade tin chloride

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preparation example Construction

[0026] Such as figure 1 As shown, a method for preparing toothpaste-grade stannous chloride includes the following steps:

[0027] (I) Synthesis reaction and primary filtration

[0028] Add deionized water to reactor 1, and then add concentrated hydrochloric acid. The added amount of concentrated hydrochloric acid is 3% to 8% of the total mass of the aqueous solution. Then, add anhydrous tin tetrachloride slowly, and finally add metallic tin. The temperature is 110~120℃, and the reaction time is 1~3h. Among them, the mass of the total aqueous solution refers to the sum of the aqueous solutions contained in deionized water and concentrated hydrochloric acid; the molar ratio of deionized water, anhydrous tin tetrachloride and metallic tin is 4~8:1:1~1.2. The mass concentration is 38%. The chemical reaction formula is:

[0029] Sn+SnCl 4 +4H 2 O→2SnCl 2 ·2H 2 O

[0030] The addition of concentrated hydrochloric acid effectively avoids the hydrolysis of tin chloride; and this me...

Embodiment 1

[0039] 2.7 kg of deionized water, 0.7 kg of hydrochloric acid, 10 kg of anhydrous tin tetrachloride, and 4.5 kg of metallic tin were added to the reactor in sequence. The reaction temperature was 110°C and the reaction time was 3 hours; after the reaction was completed, the metal solid impurities were filtered out; Add 42ml of sulfuric acid (10g / 100ml) to the filtrate, and then add 42ml of strontium chloride (saturated solution) to filter out solid impurities; take the clear solution and place it in a vacuum distiller for vacuum distillation with a vacuum of 0.01MPa and a temperature of 45 ℃; The distilled solution is introduced into the crystallization kettle to stir and crystallize at a temperature of 0℃; after the white crystals are separated, the entire material system is placed in a centrifuge for solid-liquid separation, and the solid white crystals are placed in a vacuum drying oven for drying , The vacuum degree is -0.05MPa, and the finished product is obtained. The wei...

Embodiment 2

[0041] 4.1 kg of deionized water, 0.7 kg of hydrochloric acid, 10 kg of anhydrous tin tetrachloride, and 5.0 kg of metal tin were added to the reactor in sequence. The reaction temperature was 115°C and the reaction time was 2 hours; after the reaction was completed, the metal solid impurities were filtered out; Add 40ml of sulfuric acid (10g / 100ml) to the filtrate, and then add 40ml of strontium chloride (saturated solution) to filter out solid impurities; take the clear solution and place it in a vacuum distiller for vacuum distillation with a vacuum of 0.03MPa and a temperature of 70 ℃; The distilled solution is introduced into the crystallization kettle and stirred for crystallization at a temperature of -5℃; after the white crystals are separated, the entire material system is placed in a centrifuge for solid-liquid separation, and the solid white crystals are placed in a vacuum drying oven After drying, the vacuum degree is -0.08MPa, and the finished product is obtained. ...

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Abstract

The invention discloses a preparation method of a toothpaste-grade tin chloride. The preparation method comprises the following steps: (i) synthetic reaction and primary filtration: adding deionized water, anhydrous tin tetrachloride and metallic tin into a reaction kettle according to a molar ratio of (4-8): 1: (1-1.2), and then adding concentrated hydrochloric acid to carry out synthetic reaction and primary filtration; (ii) purification and secondary filtration: adding excessive sulfuric acid into a purifying kettle, and then adding an appropriate amount of toothpaste-grade strontium chloride to carry out purification and secondary filtration; (iii) carrying out distillation and crystallization; (iv) carrying out vacuum drying, thus obtaining a finished product of dry white crystal toothpaste-grade tin chloride. The preparation method disclosed by the invention is stable in process, easy to control, low in cost and little in three wastes; the synthesized toothpaste-grade tin chloride is stable in quality and accords with addition standards of toothpaste.

Description

Technical field [0001] The invention belongs to a method for preparing toothpaste additives, and specifically relates to a method for preparing toothpaste grade stannous chloride. Background technique [0002] In the oral care industry, stannous chloride is mostly used in anti-caries desensitization toothpastes. Its main function is to reduce the solubility of tooth enamel in acid, enhance enamel remineralization, and prevent tooth decay. [0003] The traditional production method of stannous chloride is to directly react metal tin with hydrochloric acid, and then evaporate and concentrate to separate the stannous chloride dihydrate (SnCl 2 ·2H 2 O) Crystal. The prior art methods for preparing stannous chloride, such as the Chinese patent "A method for preparing stannous chloride" (CN85106332) discloses the use of metal tin, chlorine and water in the presence of hydrochloric acid to generate tin tetrachloride, and then add metal The method of tin as a reducing agent. In this meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G19/06
Inventor 刘玉静王筠朱昱周红艳郑楠
Owner RES INST OF PHYSICAL & CHEM ENG OF NUCLEAR IND
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