Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/38—Separation; Purification; Stabilisation; Use of additives
  • C07C17/42—Use of additives, e.g. for stabilisation
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
  • C23G5/02—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents
  • C23G5/028—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing halogenated hydrocarbons
  • C23G5/02854—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing halogenated hydrocarbons characterised by the stabilising or corrosion inhibiting additives
  • C23G5/02883—Nitrogen-containing compounds

Definitions

• the present invention relates to the stabilization of halogenated hydrocarbons against decomposition. More particularly it relates to the stabilization against decomposition of chlorinated hydrocarbons, and especially chlorinated aliphatic hydrocarbons such as trichloroethylene and perchloroethylene, useful as solvents in various industrial processes.
• chlorinated hydrocarbons and more particularly trichloroethylene and perchloroethylene, are widely used in various technical processes. These are especially useful as solvents for fats and other organic substances, for instance in degreasing processes for metals, in processes for the extraction of oils and fats, in the drycleaning of fabrics, etc.
• this decomposition is accelerated through the presence of metals or metal salts as Well as by the direct or indirect products of the decomposition itself, the decomposition thereby proceeding autocatalytically.
• the stabilizing system must furthermore be such as to ensure the neutrality of the solvent even under the most severe conditions (alkalinity of the solvent when imparted by stabilizers having a strong basic character is just as harmful as acidity, because such alkalinity makes the solvent quite unsuited for the degreasing of amphoteric metals such as aluminum and zinc) and furthermore the stabilizing system must exert a lasting stabilizing action both in the liquid phase as well as in the vapor phase customarily encountered during degreasing processes.
• the object of this invention is that of providing a new and efficient stabilizing agent for halogenated hydrocarbons, particularly suited for chlorinated solvents to be used in the degreasing of metals, which, besides exerting a sure and lasting anti-oxidizing action, that is, such as to ensure the inhibition of the formation of phosgene and hydrochloric acid, will also guarantee the neutrality of the solvent even under the most severe operational conditions.
• a stabilizing action of a sure and lasting effectiveness against the decomposition of halogenated hydrocarbons, and in particular of chlorinated hydrocarbons used as solvents in the degreasing of metals is achieved by adding to the halogenated hydrocarbon solvent a stabilizing composition based on the combination of butylene oxide, di-isobutylene, thymol and dimethylbenzalhydrazone.
• the above-mentioned composition may be used alone or in admixture with other stabilizers of previously known yp
• the quantity of stabilizing composition to be added to the halogenated hydrocarbon solvent depends on the type of solvent to be stabilized, on the expected use of the solvent, on the degree of stabilization desired, and on the possible presence of other additives.
• concentrations are preferably used varying from 0.1 to 0.4% by Weight of butylene oxide, from 0.01 to 0.1% by weight of di-isobutylene, from 0.001 to 0.02% by weight of thymol, and from 0.001 to 0.02% by weight of dimethylbenzalhydrazone. Although larger quantities of the several components may be used, they are not necessary.
• Trichloroethylene and perchloroethylene stabilized according to the present invention do not show any tendency to decompose either during storage or during use under the most severe processing conditions such as in the degreasing of metals. Even after long heat-treatments trichloroethylene and perchloroethylene thus stabilized remain limpid and clear.
• the stabilizing composition of this invention in combination with small quantities (for instance, 0.00050.002% by weight) of an alkyl-hydrazine, such as methyland ethyl-monoand symmetrical and/or asymmetrical di-hydrazines.
• an alkyl-hydrazine such as methyland ethyl-monoand symmetrical and/or asymmetrical di-hydrazines.
• halogenated hydrocarbons may be protected against decomposition by the stabilizing composition according to the present invention, such as chloroform, methylchloroform, methylene chloride, carbon tetrachloride, dichloroethylene, trichloroethane, vinylidene chloride, vinyl chloride, etc.
• a small steel plate of x 2 x A inch is suspended in the vapor phase while in the liquid phase a small steel plate of 4 x x inch is introduced.
• a sanded 150 watt lamp is placed under the flask.
• a liquid chlorinated hydrocarbon stabilized against decomposition comprising trichloroethylene or perchloroethylene in admixture with a stabilizing composition consisting essentially of butylene oxide, di-isobutylene, thymol and dimethylbenzalhydrazone in quantities varying, respectively, from about 0.1 to 0.4% by Weight, from about 0.01 to 0.1% by weight, from about 0.001 to 0.02% by weight, and from about 0.001 to 0.02% by weight.
• Trichloroethylene stabilized against decomposition comprising trichloroethylene in admixture with a stabilizing composition consisting essentially of butylene oxide, di-isobutylene, thymol and dimethylbenzalhydrazone in quantities varying, respectively, from about 0.1 to 0.4% by weight, from about 0.01 to 0.1% by weight, from about 0.001 to 0.02% by weight, and from about 0.001 to 0.02% by weight.
• a stabilizing composition consisting essentially of butylene oxide, di-isobutylene, thymol and dimethylbenzalhydrazone in quantities varying, respectively, from about 0.1 to 0.4% by weight, from about 0.01 to 0.1% by weight, from about 0.001 to 0.02% by weight, and from about 0.001 to 0.02% by weight.
• Perchloroethylene stabilized against decomposition comprising perchloroethylene in admixture with a stabilizing composition consisting essentially of from about 0.1 to 0.4% by weight of butylene oxide, of from about 0.01 to 0.1% by weight of di-isobutylene, of from about 0.001 to 0.02% by weight of thyme], and of from about 0.001 to 0.02% by weight of dimethylbenzalhydrazone.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Cited By (4)

Citations (2)

• 1968
  • 1968-04-16 NL NL6805316A patent/NL6805316A/xx unknown
  • 1968-04-18 FR FR148525A patent/FR1580912A/fr not_active Expired
  • 1968-04-18 DE DE19681768227 patent/DE1768227A1/de active Pending
  • 1968-04-19 BE BE713963D patent/BE713963A/xx unknown
  • 1968-04-19 US US722808A patent/US3546304A/en not_active Expired - Lifetime

Patent Citations (3)

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