CS259584B1 - Process for preparing high purity 2-propanol - Google Patents

Abstract

The binary waste mixture is continuously or dtscontinaaáfae by means of the entrainer to get rid of excess water by asentropic destillation. Z-propanel is then continuously or discontinuously distilled under reduced or aitmcepheric pressure, in an apparatus resistant to the isorous effect of the distilled medium, and the intermediate viscosity is removed, after which the distillate is passed through a microwave filter with a pore size of 6.2 gm.

Description

The invention relates to the preparation of high-purity 2-propanol using physicochemical purification methods from a waste binary mixture in a device made of a material that is resistant to the corrosive effects of 2-propanol and its accompanying impurities.

2-Propanol is used as a rinse aid in the production of electronic components. For this purpose, 2-propanol must meet strict purity criteria. 2-propanol produced by conventional refining in conventional equipment contains organic impurities — residues of unreacted input materials, products of side reactions and inorganic impurities — metal ions due to equipment corrosion, dust particles from contamination of chemicals with the ambient air.

The above-mentioned shortcomings are not inherent in the method of preparing high-purity 2-propanol from a waste binary mixture consisting of 70% by weight of 2-propanol and 30% by weight of water, which consists in distilling 2-propanol without access to air under reduced or atmospheric pressure in an apparatus whose material is resistant to the corrosive effects of 2-propanol and the distillate is passed through a system of microfilters with decreasing pore size.

The preparation of high-purity 2-propanol takes place in three technological stages:

Example

1. preparation of the azeotropic mixture 2-propanol — water,

2. azeotropic distillation of this mixture in the presence of an azeotropic carrier, e.g. benzene, methyl ethyl ketone, toluene, methyl ethyl ether, cyclohexanol,

3. purification by continuous or discontinuous distillation and filtration using distillation and filtration apparatus.

Distillation in the final purification stage can be carried out under reduced or atmospheric pressure, with the temperature t ₀ of the distillate withdrawal in °C being t ₀

1359.473 '6.86451 — log p

197.558 where p is the working pressure in the apparatus in kPa. The method of preparing high-purity 2-propanol is explained on the following example.

The input raw material, which is analytically characterized in the following text, was processed in the first technological stage batchwise on a grate rectification column with 20 stages at atmospheric pressure. The distillation apparatus was assembled from SIMAX glass parts. After the distillation regime was stabilized, the backflow on the column was set to R = 2:1. The fraction in the temperature range from 80 to 81 °C, which consisted of an azeotropic solution of 2-propanol and water, was collected as the main product.

In the second technological stage, 2-propanol with a water content of max. 0.1% by weight was prepared from an azeotropic solution of 2-propanol and water. A SIMAX distillation apparatus with a 40-stage cap column was used. Benzene was used as an azeotropic medium for removing water, which was added to the reboiler at the beginning of the process in a volume ratio of 1 part benzene to 5 parts azeotropic solution of 2-propanol with water. After the column thermal regime had stabilized, the reflux ratio R = 10:1 was set and the distillate was taken at a temperature of 66 to 67 ^° C, which had a composition of 73.8% benzene, 18.7% propanol and 7.5% water. After cooling, the distillate was divided into two layers and the lower — aqueous phase had a composition of 75% water, 9.4% 2-propanol and 15.6% benzene. The dehydration process ends when the temperature at the top of the column begins to rise to 72 °C, at which point the excess benzene is distilled off in an azeotropic mixture with 2-propanol. The removal of benzene was carried out by continuing the distillation until the temperature at the top of the column reached 82.5 °C, at atmospheric pressure.

The third technological stage of refining followed immediately, with distillation continuing under the same conditions as in the second stage and the product, 2-propanol, being collected as a fraction at a temperature of 82.5 ± 0.5 °C. After cooling to 35 °C, this distillate was fed directly to a three-stage ultrafilter. The filtration membranes had a gradually decreasing pore size, 0.8 μm, 0.45 μm and 0.2 μm. The filter body was made of grade 17 stainless steel. The filtration membranes themselves were made of polytetrafluoroethylene.

The resulting product of this three-step processing was analyzed using gas chromatography analytical methods with the following results:

2-propanol prepared acc. trigger.

253584

Table

Required Input Raw Material Values for Microelectronics Reagent Mixture

2-propanol content (%) 99.7 69.3 99.9 water content (%) max. 0.1 30.7 0.1 evaporate (ppm) max. 5.0 10.0 5.0 calcium Ca (ppm) max. 0.5 0.55 0.4 potassium K (ppm) max. 0.1 1.9 0.09 magnesium Mg (ppm) max. 0.1 20.0 0.09 chromium Cr (ppm) max. 0.02 1.5 0.02 iron Fe (ppm) max. 0.1 0.22 0.01 sodium Na (ppm) max. 0.5 9.5 0.01 heteroparticles 1 to 5 μΐη max. 20,000 dm ^-3 125,000 cubic ^meters 1,350 dm ^-3 5 to 25 /im max. 3,000 dm ~ ³ 11,200 cubic ^meters 1100 ^dm3 over 25 μΐη max. 500 ^dm3 830 dm- ³ 325 ^dm3

SUBJECT

Claims (1)

2-propanol prepared as above; spOs. 253584 Table Required Input raw material microelectronic mix mix 2-propanol content (% j 99.7 69.3 99.9 water content (%) max 0.1 30.7 0.1 rpm (ppmj max. 5.0 10.0 5.0 calcium Ca (ppmj max. 0.5 0.55 0.4 potassium K (ppmj max. 0.1 1.9 0.09 magnesium Mg (ppmj max. 0.1 20, 0 0.09 chromium Cr (ppmj max. 0.02 1.5 0.02 iron Fe (ppmj max. 0.1 0.22 0.01 sodium Na (ppmj max. 0.5 9.5 0.01 heterocomponent 1 to 5 μΐη max. 20 000 dm-3 125 000 dm'3 1 350 dm-3 5 to 25 μΐη max 3 000 dm ~ 3 11 200 dm "3 1100 dm'3 above 25 μΐη max. 500 dm" 3 830 dm 3 325 dm 3 METHOD Preparation of high-purity 2-propanol from a 70-w / w 2-propanol waste binary mixture and 30 w / w% water, wherein 2-propanol is distilled under reduced pressure. or atmospheric pressure in the apparatus, the material of which is resistant to the corrosive effect of distilled copper, whereby a fraction at a mean temperature of t 0 + 0.5 ° C is taken by the invention where t0 is the boiling temperature corresponding to the working fluid in which the distillation is carried out in ° C and the p is the working pressure in the apparatus in kPa, and the distillate is passed directly through the microfilter system with a porosity of 0.8 to 0.2 µm. t, 1359.4736.86451 - log p 197.558