CS240535B1 - A method of preparing high purity trichloroethylene - Google Patents

Abstract

The method of preparation of high-purity trichlorethylene of MOS Selectipur purity from pre-produced trichlorethylene of technical purity and/or from immediately extracted, its possible physico-chemical refining, stabilization and, as a rule, treatment is carried out by taking trichlorethylene from a distillation or rectification column into a master, in which it is stabilized with at least one oxygen-containing organic antioxidant with a molar mass of 140 to 360 g. ■ . mol-1 in the amount of 1.10~4 to 1.10-2 (2 . . 10-3 to 4. io3) % wt. Oxygenated organic antioxidants are cumylphenols, benzylmethylphenols and dibenzylmethylphenols as well as 1-phenoxy-1-phenylethane, alkylphenol or dialkylphenol with 4 to 16 carbon atoms in the alkyl.

Description

240535

BACKGROUND OF THE INVENTION The present invention relates to the preparation of high purity chloroethylene purity MOS Selectipur by the treatment of technology and the use of efficient and technically available stabilizers.

Trichlorethylene is a chlorinated hydrocarbon that is used as degreasing agent in engineering, electrical engineering and elsewhere. In all of its applications, the content of hydrochloric acid is carefully monitored, which, as a strong mineral acid, can interfere with the metal object or electrotechnical component. Hydrochloric acid is formed mainly by the action of oxygen trichlorethylene. The mechanism of formation is likely to be that the reaction of oxygen with dichloromethane results in dichloroacetyl chloride which decomposes to form phosgene, carbon monoxide, and hydrogen chloride. The trichloroethylene oxygen catalyst catalyzes or initiates heat and light. To prevent this reaction, a stabilizer must be added to the trichlorethylene.

To date, several types of stabilizers have been used. In U.S. Pat. No. 2,795,623 (1957), N-methylpyrrole is recommended, optionally in combination with butylacetoacetate. The acidity of trichlorethylene and its effluent is expressed in milliliters of 0.1HCl. In the same patent, copper (II) acetoacetate, aluminum methyl salicylate and aluminum e-ethyl acetoacetate were also tested in addition to copper acetoacetate. However, all of these stabilizers were added in amounts around. 1 ° / Watt. In U.S. Pat. No. 2,818,446 (1957), epoxy-containing substances are protected as stabilizers, for example: epichlorohydrin, butylene oxide, optionally in combination with ethyl acetate, methyl acrylate or methyl propionate. These stabilizers are added in an amount of 0.1 to 0.3% by weight. Oxirane oxygen compounds are protected by V. Brit. No. 794,700, wherein, for example, butylene oxide is used as a stabilizer in an amount of 0.2% by weight, optionally in combination with triethylamine in an amount of 0.001% by weight. The stabilizing effect is evaluated by measuring the pH of the aqueous extract of trichlorethylene. In addition to these substances, many other agents are known as stabilizers: amines. (diisopropylamine, triethylamine, aniline), borate esters, acetone, hydrazines, hydrazones, aliphatic isocyanates, lactones, o-nitrophenol, nitrogenous heterocyclic compounds (e.g. pyrrole, pyrazole and derivatives thereof), oxygenated heterocyclic compounds wound, tetrahydrofuran and the like), sulfur heterocyclic compounds (tetrahydrothiophene, thiazole), sulfur dioxide, esters of stearic acid, aliphatic alcohols (isobutanol, n-pentanol, pro-pargylalcohol), aromatic alcohols (phenol, o -cresol, p-butyl-o-methylphenol, p-tert-butyl-1,2-dihydroxybenzene).

Increases trichlorethylene to be used. ... '... Me. In the manufacture of microelectronics, it must comply with a number of specific requirements: a) Amino or isocyanates which give amine reaction must not be used as stabilizers; b) Substances containing, for example, boric acid esters, must not be used; acetyl acetate, aluminum, since the total content of these metals must not be higher than 1.10% 4% by weight in trichloroethane; (1 ppm), c) not also be used as stabilizers, which, by their odor, exacerbate the atmosphere, or are potentially carcinogens, or mutagens (epichlorohydrin, pro-pylene oxide), e) the stabilizer content in trichlorethyleneeproelectronics can be up to 4 . 10-3 o / w wt. (40 ppm).

On the other hand, the acidity of trichlorethylene is up to 10 times lower than that of trichlorethylene for other purposes. A high-efficiency stabilizer must be used from these effluents.

The stability of trichlorethylene is usually tested in the laboratory by determining the acidity by titration with a 0.01 M sodium hydroxide solution as an indicator. Trichlorethylene of good quality, if the titration solution is 0.5 cm 3 for titration of 50 g of tri-chloroethylene.

Therefore, it was necessary to search and test such a stabilizer that would meet all of the above requirements. The stabilizers used so far are either less effective or have corrosive and other undesirable side effects in the application. In this context, one of the main causes of the deterioration in the quality of trichloroethene, which is oxygen, has been found to elucidate the mechanism of its quality-reducing effect, mainly due to the increase in the acidity of trichlorethylene and the subsequent development of a high-purity process. trichlorethylene.

According to the present invention, the process for the preparation of trichlorethylene of purity MOS Selectipur from free-produced trichlorethylene is technically and chemically pure and / or is produced directly from trichlorethylene, by its physicochemical refining, stabilization and, as a rule, treatment, so that trichlorethylene is removed from the distillation process. the boronification column is withdrawn into a template in which at least one of the acidic organic antioxidants of the phenolic type is stabilized with a molar mass of 140 to 400 grams. mole-1 at 1.10-4-4. 10% 2 wt.

The high purity trichlorethylene grade MOS Se- lectipur is characterized not only by its low free acid content (10 ppm), but by its low content of heavy metals (up to 1 ppm), alkali metals (up to 0.5 ppm) and the limited number of hetero- particles of a certain grain size. An advantage of the process of the present invention to achieve a relatively long-term stability of pure pure trichloroethane, which is relatively easy to produce, is to produce high purity stable trichlorethylene, both commercially available in conventional qualities of trichloroethane, and to provide, by simple modification, the preparation of high purity. trichlorethylene from conventional high-density trichlorethylene. In an unexpected manner, the advantage is the wide range of ‘technically easy-to-use stabilizers.

The trichloroethene prepared by the combination of the present invention from its purity and stability is suitable for the most demanding applications.

By physico-chemical refining, the removal of volatile debonders, such as diethylamine and the like, further distillation or rectification, co-operation of the " chlorine trap ", such as epoxy compound (epi-chlorohydrin, epoxidized oils, and the like), solid or at least low-viscosity infusion compositions such as urea, n-ethanolamine, diethanolamine, hexamethylene tetramine, and the like, prior to distilling off the chloroethylene. The treatment is meant to mean the filtration of any solid particles, or their separation.

Oxygen organic antioxidants are in particular cumylphenols (2-cumylphenol, 4-cumylphenol), benzylmethylphenols [1-phenyl-1- (2-hydrophenyl) ethane, 1-pheny1-1. (4-hydroxyphenyl) and dibenzylmethylphenols, phonoxyphenols, alkoxyphenols, alkylphenols to trialkylphenols, mainly with C-aphthyl alkyls of 4 to 16. Of these, mainly nonylphenol, octylphenol, 2,4-dioctylphenol , 4-tert-butylphenol, 2,4-di-tert-butylphenyl, 2,6-di-tert-butyl-4-methylphenol, tert-butyl cumylphenol and di-tert-butyl- cumylphenol ap.

The amount of stabilizer in trichloroethylene may not be in the range of 1.14 to 1.10% by weight, but pertrichlorethylene for a number of uses, such as in the manufacture of high purity components for microelectronics, requires the presence of a stabilizer at most 4. 10 ~ 3 wt.

It is suitable to operate in an inert atmosphere which is achieved by removing air by coagulating or feeding or blowing an inert gas, such as pure nitrogen, arginine, carbon dioxide, etc., because oxygen is the primary cause of the low stability of trichlorethylene. Its positioning on trichlorethylene ultimately results in phosgene, chlorine-hydrogen and carbon monoxide.

The method of the invention can be carried out continuously, semi-continuously and continuously.

Further details of the method as well as other advantages are apparent from the examples. Example 1

In a 500 cm 3 glass flask of conventional chemical glass, 30 cm 3 of tri-chloroethylene and 1.75 cm 3 of trichloroethylene solution of 1-g / 100 cm 3 of trichlorethylene as a stabilizer are added. The cumylphenol used was 91% of 4-cumylphenol and 8% of 2-phenylphenol had a melting point of 68-69.5 ° C and a hydroxyl content of 9.35% by weight. (theory 9.34%).

Thereafter, the change in acidity of the titrated samples of trichlorethylene is monitored in amounts of 5 g.

The results are shown in Table 1.

Table -1

Exposure time Consumption of aqueous - storage of 0,01 M NaOH / 50 g (day) trichlorethylene 1 0,27 .cm3 3 0,25 cm3 6 0,31 cm3 9 0,30 cm3 13 0,28 cm3 16 0,24 cm3 0.30 cm < 3 > Example 2 Similar to Example 1, but no trichlorethylene is added to trichlorethylene. Depending on the time, the variation in sample kysleate is shown in Table 2. Table 2 Exposure Time Consumption of aqueous - storage of 0.01 M NaOH / 50 g (day) trichlorethylene solution 1 0.27 cm 3 2 2.50 cm 3 3 not applicable stitrovat Example 3

The procedure is similar to Example 1, except that the stabilizer adds 1.75 cm 3 of the trichlorethylene solution of the phenol arylalkylation product to styrene at a concentration of 1% by weight. The specification of the product of the arylalkylation of phenol by styrene is as follows: at room temperature the viscous-liquid and consists of 22.1%. % phenols, 18.6 wt. 1-phenoxy-1-phenylene and 55.6% by weight of 1-phenyl-1 (4-hydroxyphenyl) ethane with 1-phenyl-1 (2-hydroxyphenyl) ethane. The hydroxyl content is 8.96% by weight. and the lomunD20 index = 1.5888.

The results of the stabilization of trichloro-ethylene are shown in Table 3. 240535

Table 3

Exposure time of chlorofluoroethylene - storage (days) Consumption of an aqueous solution of 0.01M NaOH / 50 gtrichlorethylene Table 4 Exposure time - storagefirrichlorethylene (days) 1 0.27 cm3 3 6 0.28 cm3 0.25 cm3 1 9 0.28 cm3 3 13 0.25 cm3 6 16 0.21 cm3 9 19 0.32 cm3 13 Example 4 Example 5 The procedure is similar to Example 1, instead of the cumylphenol solution, 1.75 cm 3 of trichlorethylene solution 2,6-di-tertiary is added -butyl-4-methylphenol at a concentration of 1 wt. The 2,6-di-tert-butyl-4-methylphenol used is a white crystalline substance with a melting point of 67.5 to 68.5 ° C. The hydroxyl content is 7.60% by weight. (theoretically 7.72% by weight) The results of the stabilization of tri-chloroethylene thus obtained are evident from the results in Table 4.

Consumption of an aqueous solution of 0.01 M NaOH / 50, trichlorethylene 0.27 0.25 0.41 0.50 0.75 cm 3 cm 3 cm 3 cm 3 cm 3 as in Example 3, only the styrene aralkylated phenol is added to the three flasks and a first bank of 1.10 ~ 3 wt. (10 ppm); % (20 ppm) and 3.10% by wt. (30 ppm). The changes in acidity of trichlorethylene are monitored at day intervals. The results obtained are summarized in Table 5.

Table 5

Exposure time - storage of trichlorethylene (days)

Consumption of 0.01 M NaOH solution / 50 g-trichlorethylene content of stabilizer 1. 10-3% (10 ppm) 2.ΙΟ "3% (20 ppm) 3" 10 "3" / (30 ppm) 1 0.20 cm3 0.20 cm3 0.20 cm3 3 0.27 cm3 0.19 cm3 0.19 cm3 6 0.81 cm3 0.44 cm3 0.24 cm3 9 1.00 cm3 0.98 cm3 0.26 cm3 13 - Example 6 The results of the change in the acidity of trichlorethylene from the amount of added are obtained. Similar to Example 5, cumylphenol and time are shown in Table 1 only as cumylphenol. to 6. Table 6 Exposure time - glass - Consumption (in cm3) of aqueous trichlorethylene solution of 0.01 M NaOH / 50 g (days) trichlorethylene content of cumylphenol added to trichlorethylene 1.10-3% 2.ΙΟ'3% 3.10 "3% (10 ppm) (20 ppm) (30 ppm) 1 0.20 0.19 0.20 0.33 0.22 0.22 6 0.64 0.23 0.23 9 0.75 0 , 44 0.43 13 - 0.60 0.56

Claims (6)

EXAMPLE 7 The procedure is similar to that in Example 5 except that nonylphenol is used as a stabilizer at 3.10% by weight (30 ppm) and 86% by weight benzylmethylphenol is used as the stabilizer. 1-phenyl-1 (4-hydroxyphenyl) ethane with 1-phenyl-1 (2-hydroxyphenyl) ethane], 6.5% w / w dibenzylmethylphenols [C 6 H 5 CH (CH 2) 2] C 6 H 3 OH, 0.8% w / w phenol and 6.8% by weight of 1-phenoxy-1-phenylethane The results are shown in Table 7. Table 7 Exposure Time - Storage Consumption (in cm 3) of an aqueous solution of 0.01 M NaOH / 50 g trichlorotrichlorethylene (day) ethylene trichlorethylene stabilized n-trichlorethylene stabilized with phenylphenol benzylmethylphenols 1 3 6 8 10 13 16 19 0.21 0.24 0.19 0.29 0.29 0.37 0.31 0.37 0.30 0.35 0.31 0.35 0.31 0.36 0.35 0.38 EXAMPLE 8 Commercial trichlorethylene is rectified with a TP of 10 at a reflux ratio of 1: 5 in an inert atmosphere, prior to injection into the rectification column or column boil at -dá 1 6% by weight epoxidized vegetable oil and 0.7% by weight. ureas, calculated on PREMIUM 1. A process for the preparation of trichlorethylene pure MOS Selectipur from preformed trichlorethylene technical to chemical purification and / or immediate production of trichlorethylene, by its possible physicochemical refining, stabilization and, as a rule, treatment, wherein the trichloro-thylene is removed from the distillation or rectification coil into a master in which it is stabilized by at least one of the oxygenated organic antioxidants of the phenolic type with a weight of 140-400 gm -1 in an amount of 1.10-4-4.10-2% by weight . 2. A process as claimed in claim 1, wherein the trichlorethylene is stabilized by at least one aryl alkylphenol of the formula C6H5CR'R 'C6H5OH in which R' and R 'are both identical and identical to H and CH 3, preferably 2-cumylphenol, 4-ketylphenol, 1-phenyl-1 (2-hydroxyphenyl) ethane, 1-phenyl-1 (4-hydroxyphenyl) ethane and / or diaryl-alkylphenol of formula (C6H5CR'R) ") 2C 6 H 5 OH where trichlorethylene. The rectified trichloroethylene is immediately passed through a particulate filter into a 200 dm 3 container with 3 g of cyclohexylphenol, 4 g of nonylphenol and 1 g of cumylphenol. The consumption of aqueous sodium hydroxide solution at a concentration of 0.01 M per 50 g of trichlorethylene sample after 16 days is 0.28 cm 3. EMBODIMENTS R ‘and R majú are as defined above with the preference for dibenzylmethylphenols in amounts of 1. 1 to 10% by weight, preferably 2 to 10 to 4% by weight; 3. A process for the preparation of high purity trichloroethylene according to claim 1, characterized in that the trichlorethylene is stabilized by at least one alkylphenol to trialkylphenol with the number of carbon atoms in the alkyl of 4 to 16, preferably octylphenol, mono-tert-butyl-p-cresol and % di-tert-butyl-p-cresol, in an amount of 1-10% by weight to 1.10% by weight; 4. A process for the preparation of high purity trichloroethylene according to claim 1, characterized in that the trichlorethylene is stabilized by at least one phenoxyphenoil, preferably 1-phenoxy-1-phenylethane and / or cycloalkylphenol, preferably cyclohexylphenol. 5. A process according to claim 1, wherein the trichlorethylene is stabilized with tert-butylcyclohexylphenol and / or di-tert-butylcoumylphenol. 6. A process according to claim 1, wherein the trichlorethylene is stabilized with tert-butyl benzylmethylphenol and / or di-tert-butylbenzylmethylphenol.