Preparation method of 2, 2-difluoroethanol

A technology of difluoroethanol and ethyl difluoroacetate is applied in the field of preparation of 2,2-difluoroethanol, and can solve the problems of low yield, decrease in total yield, increase production cost and the like, and achieve reduction in production cost, Emission reduction effect

Inactive Publication Date: 2014-10-15
南通得宝氟化学有限公司 +1
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AI-Extracted Technical Summary

Problems solved by technology

[0005] Using 1,1-difluoro-2-bromo (or chloro)ethane as a raw material, there are many reaction steps and a long time, resulting in a decrease in its total yield
[0006] Using difluoroacetyl chloride as the starting material is the main method of industrial production at present, the reaction reagent is easy to obtain, and the catalyst can be recycled; but the catalyst is expensive and the yield is not high, which increases the production cost
[0007] Using difluoroacetic acid or difluoroacetic acid ester as the starting material, the reaction is relatively simple, especially when difluoroacetic...
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Abstract

The invention provides a preparation method of 2, 2-difluoroethanol. The preparation method comprises the steps as follows: when an organic solution is neutralized to the temperature of subzero 20 DEG C-0 DEG C, methyl difluoroacetate or ethyl difluoroacetate is taken as a raw material, lithium aluminum hydride is taken as a reducing agent, and high-yield and high-purity 2, 2-difluoroethanol is obtained. The method is simple and convenient and can be applicable to large-scale industrial production, and the raw material is easy to obtain.

Application Domain

Organic compound preparationHydroxy compound preparation

Technology Topic

Ethyl esterChemistry +5

Image

  • Preparation method of 2, 2-difluoroethanol
  • Preparation method of 2, 2-difluoroethanol

Examples

  • Experimental program(1)

Example Embodiment

[0025] Implementation examples
[0026] · In a 2000 mL three-necked flask, 38.0 g (1.0 mol) of LiAlH4 was dissolved in 800 mL of tetrahydrofuran. The system was cooled to -10°C in an ice bath, stirred vigorously, and 248 g (2.0 mol) of ethyl difluoroacetate was slowly dropped into the three-neck flask. After the dropwise addition is completed, react for 1 hour, and nuclear magnetic F spectroscopy confirms that the conversion is complete. Use 2mol/L hydrochloric acid to adjust the pH to about 3 to terminate the reaction. The crude product of difluoroethanol can be obtained by distillation.
[0027] · In a 2000 mL three-necked flask, 38.0 g (1.0 mol) of LiAlH4 was dissolved in 800 mL of ethylene glycol dimethyl ether. The system was cooled to -10°C in an ice bath, stirred vigorously, and 248 g (2.0 mol) of ethyl difluoroacetate was slowly dropped into the three-necked flask. After the dripping is completed, react for 1 hour, and nuclear magnetic F spectroscopy confirms that the conversion is complete. Use 2mol/L hydrochloric acid to adjust the pH to about 3 to terminate the reaction, and distillation can obtain the crude difluoroethanol product.
[0028] In a 2000 mL three-necked flask, 38.0 g (1.0 mol) LiAlH4 was suspended in 800 mL toluene. The system was cooled to -10°C in an ice bath, stirred vigorously, and 248 g (2.0 mol) of ethyl difluoroacetate was slowly dropped into the three-necked flask. After the dripping is completed, react for 1 hour, and nuclear magnetic F spectroscopy confirms that the conversion is complete. Use 2mol/L hydrochloric acid to adjust the pH to about 3 to terminate the reaction, and distillation can obtain the crude difluoroethanol product.
[0029] In a 2000 mL three-necked flask, 22.8 g (0.6 mol) LiAlH4 was suspended in 800 mL toluene. The system was cooled to -10°C in an ice bath, stirred vigorously, and 248 g (2.0 mol) of ethyl difluoroacetate was slowly dropped into the three-neck flask. After the addition, the reaction was carried out for 1 hour, and the NMR F spectrum showed that only 80% of the raw material was converted.
[0030] In a 2000 mL three-necked flask, 30.4 g (0.8 mol) LiAlH4 was suspended in 800 mL toluene. The system was cooled to -10°C in an ice bath, stirred vigorously, and 248 g (2.0 mol) of ethyl difluoroacetate was slowly dropped into the three-neck flask. After the addition was completed, the reaction was carried out for 1 hour, and the NMR F spectrum showed that only 94% of the raw material was converted.
[0031] In a 2000 mL three-necked flask, 53.2 g (1.4 mol) LiAlH4 was suspended in 800 mL toluene. The system was cooled to -10°C in an ice bath, stirred vigorously, and 248 g (2.0 mol) of ethyl difluoroacetate was slowly dropped into the three-necked flask. After the dripping was completed, the reaction was carried out for 1 hour, and the nuclear magnetic F spectrum showed that more than 99% of the raw materials had been converted.
[0032] In a 5000 mL three-necked flask, 106.4 g (2.8 mol) LiAlH4 was suspended in 2000 mL toluene. The system was cooled to -10°C in an ice bath, stirred vigorously, and 868 g (7.0 mol) ethyl difluoroacetate was slowly dropped into the three-necked flask. After the dripping was completed, the reaction was carried out for 1 hour, and the nuclear magnetic F spectrum showed that more than 99% of the raw materials had been converted.
[0033] The crude product of difluoroethanol is purified by distillation column rectification, and the fraction with a boiling point of 95-96°C is collected, and the GC purity is above 99.5%. 19F NMR(376MHz, cdcl3)δ-128.19(t,J=15.2Hz),-128.27(dt,J=55.7,15.3Hz),-128.34(t,J=15.2Hz).1H NMR(300MHz,MeOD) δ5.83 (tt, J = 55.8, 3.8 Hz, 1H), 3.70 (td, J = 15.1, 3.8 Hz, 2H).
[0034] The rectified ethanol/methanol can be fed again and recycled, which not only reduces production costs but also reduces emissions, which is beneficial to environmental protection.
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Classification and recommendation of technical efficacy words

  • Reduce manufacturing cost
  • Emission reduction
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