SE445826B - STABILIZED 1,1,1-TRICHLORETAN COMPOSITION - Google Patents

Description

7905627-1 2 fatty alcohol with up to 5 carbon atoms. However, since 1,1,1,1-trichloroethane itself is particularly sensitive to decomposition at the temperatures prevailing in its use as a degreaser and / or detergent due to the presence of grease, metal surfaces and metal contaminants suspended in the cleaning bath , these combinations of stabilizers are not capable of stabilizing 1,1,1,1-trichloroethane. nor does the combination of the three constituents nitromethane / tert-butyl alcohol butene oxide-1,2, described in U.S. Pat. No. 3,281,480, prevent the formation of a yellowish precipitate in the solvent after 24 hours of contact with aluminum. The same applies to monohydroxylated aliphatic acetylene alcohols having at least 8 carbon atoms, in particular 2-methyl-3-butyn-2-ol, in combination with 1,4-dioxane, according to U.S. Pat. No. 2,838,458.

The object of the present invention is to remedy the above-mentioned disadvantages while at the same time achieving an efficient and more lasting stabilization of 1,1,1,1-trichloroethane under very stressful working conditions, and to make it possible to perform degreasing and / or cleaning of metal parts , plastic materials, textile materials and other materials without any appreciable deterioration of either solvents or treated materials.

The stabilized 1,1,1-trichloroethane composition according to the invention contains as essential stabilizers. a) 0.5 - 5% by weight and preferably 0.5 - 3.5% by weight of tert-butyl alcohol, b) 0.1 - 5% by weight and preferably 0.3 - 3% by weight of at least one of the compounds 2-methyl-3-butyn-2-cl and trioxane, c1 0.1 - 5% by weight and preferably 0.2 - 3% by weight of at least one optionally chlorinated epoxide having 3 to 8 carbon atoms. d) 0.1 - 3% by weight of at least one nitroalkane having 1-3 carbon atoms J 28) 0.001 - 1% by weight and preferably 0.005 - 0.1% by weight of at least one cyclic or heterocyclic aliphatic amine having 4-10 f) Stabilized 1,1,1-trichloroethane composition, characterized in that it contains as essential stabilizers: a) 0.1-5% by weight and preferably 0.5 -3.5% by weight of tert-butyl alcohol, b) 0.1-5% by weight and preferably 0.3-3% by weight of at least one of the compounds 2-methyl-3-butyn-2-ol and trioxane, c) 0.1-5% by weight and preferably 0.2-3% by weight of at least one, optionally chlorinated, epoxide having 3-8 carbon atoms, d) 0.1-3% by weight of at least one nitroalkane having 1 -3 carbon atoms, 0.001-1% by weight and preferably 0.005-0.1% by weight of at least one cyclic or heterocyclic aliphatic amine having 4-10 carbon atoms e) and having a basic character, and f) 0-1% by weight and preferably between 0.001 and 0.1% by weight of at least one antioxidant selected from phenols and the heterocyclic nitrogen compounds the purifications with 3-5 carbon atoms and 1-2 nitrogen atoms and, optionally, 1 oxygen atom in the ring.

According to the invention, the amines corresponding to this definition are selected from the aliphatic amines, preferably the secondary or tenderness, straight or branched chain; among the aromatic amines having 6 carbon atoms substituted by halogen atoms or alkyl groups having 1-3 carbon atoms; and among the heterocyclic amines having 1 to 2 nitrogen atoms in the molecule. As non-limiting compounds such as ethylamine, diisopropylamine, di-sec-butylamine, amylamines, hexylamines, pyridines, picolines, morpholine, N-alkylmorpholine in which the alkyl moiety has 1-3 carbon atoms, pyrrolidine and N-pyrrolidine and N-pyrrolidine in which the alkyl moiety has 1-3 carbon atoms.

The amines which are particularly advantageous according to the invention are N-methylmorpholine, diisopropylamine and pyrrolidine.

In the description given below to clarify the invention, the stated percentages refer to weight percent, unless otherwise stated.

In the case where the mixture of tert-butyl alcohol and 2-methyl-3-butyn-2-ol is combined with 1,1,1-trichloroethane, this bi- nal mixture consists of 1-99% tert-butyl alcohol and 99-1% 2-methyl-3-butyr-z-ol, and preferably of 25 - ao z cerc-butyl alcohol and 75 - 20% 2-methyl-3-butyn-2-ol. l? According to an advantageous embodiment of the invention, trioxane is added to 1,1,1-trichloroethane in an amount of 0.5 to 3%, without the addition of 2-methyl-3-butyn-2-ol ; As compounds representative of the optionally chlorinated epoxide having 3-8 carbon atoms may be mentioned in particular epichlorohydrin, glycidol and the primary, secondary and tertiary methyl-n ethyl, propyl, isopropyl, allyl or butyl ethers thereof, propylene oxide 1,2, styrene oxide, cyclohexene oxide and preferably butene oxide-1,2. The preferred quantities of eporide added are between 0.2 and 3%, based on 1,1,1,1-trichloroethane.

The nitroalkanes, of which at least one is added but preferably a mixture of at least two, consist of nitromethane, nitroethane and the two isomers of nitropropane. The quantity to be preferably added is between 1 and 2%, calculated on the trichloroethane.

In fact, it has been found that the combination of the above-mentioned compounds has been found to be particularly advantageous as, at comparable concentration, it has a stabilizing effect which is clearly greater than the stabilizing effect obtained with each of the various constituents.

Examples of phenols are the mcnophenols, e.g. phenol, cresols, ethylphenols, butylphenols and in particular p-tert-butylphenol, thymol, naphthols, methylnaphthols, eugenol, the alkoxy ethers having 1 or 2 carbon atoms of monophenols such as anisole, guaiacol and the 2-ethoxyphenol diphenols, e.g. resorcinol, pyrecatechol, naphthoquinone and in particular hydroquinone, the alkoxy ethers having 1 or 2 carbon atoms of these diphenols, e.g. the monomethyl ether of hydroquinone; and the triphenols, e.g. pyrogallol, fluoro-glucinol, hydroxyhydroquinone and the trihydroxytoluenes.

Examples of heterocyclic compounds having 1 nitrogen atom are pyrrole, N-alkylpyrroles in which the alkyl group has 1-4 carbon atoms, and preferably N-methylpyrrole; indole, 1-methylindole, 2-butylindole, 2-phenylindole, 2-tolylindole, 2-butylindole and their respective isomers; oxazole and isoxazole are representative heterocyclic compounds with 1 nitrogen atom and 1 oxygen atom.

Examples of heterocyclic nitrogen compounds having 2 nitrogen atoms are imidazole, pyrazole, pyrazoline, pyrazolidine, imidazoline, imidazolidine, piperazine or the N-alkyl derivatives thereof, where the alkyl group has 1-4 carbon atoms, pyrazine, pyrimidine and pyridazine.

The preferred compositions of the invention consist essentially of 1,1,1-trichloroethane containing: a) 1,5-tert-butyl alcohol, b) 0.5 2,5% of 2-methyl-3-butyn-2-ol and up to 2.5% trioxane, c) 0.2 3% butene oxide-1.2 d) 0.5 - 1.5% nitromethane and / or nitroethane, e) 0 005 - 0.1% N-methylmorpholine and / or diisopropylamine.

The following examples are only intended to illustrate in a non-limiting manner the invention and the particular advantages associated therewith.

Example 1 The following compounds were mixed in 1,1,1-trichloroethane: tert-butyl alcohol 2.0% 2-methyl-3-butyn-2-ol 1.5% butene oxide-1.2 0.45% nitromethane 1.3% N-methylmorpholine 0.008% The resulting composition was tested by successive distillation, which meant that it was distilled successively 4 times, with each distillation collecting only 90% of the volume. With each of the four distillates experiments were performed with scraping from aluminum plates according to the standard ASTM D 2943-71 T. 79056274 The purpose of this scraping test was to determine the ability of the combination of stabilizers to prevent decomposition of 1,1,1-trichloroethane. chlorinated solvents in the presence of aluminum or aluminum alloy. The experiment consisted of dipping a cleaned and degreased piece of metal, grade AA 1100 (ASTM standard corresponding to aluminum A 45 with the designation AFNOR), dipped in 50 cm 3 of stabilized 1,1,1-trichloroethane at ambient temperature and scraped with a soft rod. steel. After a sufficient period of time (1 hour), to allow reaction of any kind, the presence or absence of blisters, color of the solvent and the presence of precipitated resinous products were noted. The 1,1,1-trichloroethane was expediently stabilized if no reaction was observed.

The above composition passed the test without any sign of reaction being observed on the aluminum plates.

A very demanding stabilization test with a long duration was also carried out, the so-called BAM test (Bundesanstalt für Material-prüfung, Federal Republic of Germany). This test consisted of stabilizing l, l, l-trichloroethane and 100 cm3 with a mixture of 100 cm3 toluene performed 3 experiments: experiment 1: addition of 18 g small aluminum plates and 0.7 g aluminum chloride experiment 2: equal to experiment 1 + 1 g zinc stearate experiment 3: equal to experiment 1 + 10 ml oleic acid In each experiment the mixtures were brought to reflux keeping the bath temperature at 114 ° C for 18 hours.

The stabilized 1,1,1,1-trichloroethane was then distilled into three equal fractions in accordance with the standard DIN 51 751, after which 100 cm3 of each of the fractions in admixture with 100 cm3 of toluene were performed exclusively. The solvent was considered to meet the requirements. in the experiment of 7905627-1 no severe exothermic reaction could be recorded during the course of each of six separate experiments.

The above composition underwent the test without any strong exothermic reaction being observed.

Example 2 1,1,1-Trichloroethane containing: tert-butyl alcohol 2.0% 2-methyl-3-butyn-2-ol 1.85% butene oxide-1.2 0.45% nitroethane 1.3% pyrrolidine 0, 01% successfully passed the successive distillation test and the BAM test, respectively, both described in Example 1.

Example 3 1,1,1-Trichloroethane to which was added: tert-butyl alcohol 1.7% 2-methyl-3-butyn-2-ol 2.0% butene oxide-1.2 0.45% nitroethane 0.6% nitromethane 0.5% N-methylmorpholine 0.005% also passed the successive distillation test and the BAM test respectively, both described in Example 1.

Example 4 1,1,1-Trichloroethane to which was added: tert-butyl alcohol 2.0% 2-methyl-3-butyn-2-ol 1.5% butene oxide-1.2 0.45% nitromethane 1.3% N-methylpyrrole 0.008% N-methylmorpholine 0.01% 7905627-1 also excellently passed the successive distillation test and the BAM test, respectively, both described in Example 1.

Example 5 To demonstrate the advantage of adding an amine together with the other stabilizers of the invention, the following experiments were performed: 98 ml of stabilized 1,1,1,1-trichloroethane and 2 ml of a mixture of petroleum naphtha and water (in the ratio 90 vol. % naphtha and 10% by volume of water) was refluxed for 72 hours. The pH of the solvent was measured before and after the experiment.

In 1,1,1-trichloroethane stabilized with the composition given in Example 4 but without N-methylmorpholine, the pH was higher than 6.7 before the experiment and 4.5 after 72 hours of reflux (at this pH it is known that the solvent has a pronounced corrosive effect on degreasing machines).

In 1,1,1-trichloroethane stabilized with the composition given in Example 4 (containing 0.01% N-methylmorpholine), the pH was still 8.3 after 72 hours reflux. At this pH value, the degreasing machines are practically not exposed to any corrosion.

Example 6 1,1,1-Trichloroethane containing the following compounds: tert-butyl alcohol 2.4% 2-methyl-3-butyn-2-ol 2.1% methylglycidyl ether 0.5% nitromethane 1.3% diisopropylamine - 0.005% clarified excellent the successive distillation test and the BAM test, respectively, both described in Example 1. 7905627-1 ÉšÉEEÉl_Z The following composition also excellently passed the successive distillation test and the BAM test, respectively, both described in Example 1: 1,1,1,1-trichloroethane 94.995% tert -butyl alcohol 2.5% trioxane 1.4% butene oxide-1.2 0.4% nitromethane 0.7% N-methylmorpholine 0.005%

Claims (6)

7905627-1 ȕo Patentkrav Stabilized 1,1,1-trichloroethane composition, characterized in that it contains as essential stabilizers: a) 0.1-5% by weight and preferably 0.5-3.5% by weight of tertiary butyl alcohol, b) 0.1-5% by weight and preferably 0.3-3% by weight of at least one of the compounds 2-methyl-3-butyn-2-ol and trioxane, c) 0.1-5% by weight % and preferably 0.2-3% by weight of at least one, optionally chlorinated, epoxide having 3-8 carbon atoms, d) 0.1-3% by weight of at least one nitroalkane having 1-3 carbon atoms, e) 0.001-1 % by weight and preferably 0.005-0.1% by weight of at least one cyclic or heterocyclic aliphatic amine having 4-10 carbon atoms and having a basic character, and f) 0-1% by weight and preferably between 0.001 and 0.1% by weight of at least one antioxidant selected from phenols and the heterocyclic nitrogen compounds having 3-5 carbon atoms and 1-2 nitrogen atoms and, optionally, 1 oxygen atom in the ring. Composition according to Claim 1, characterized in that it contains a binary mixture of tert-butyl alcohol and 2-methyl-3-butyn-2-ol, preferably consisting of 25-80% by weight of tert-butyl alcohol and 75%. -20% by weight of 2-methyl-3-butyn-2-ol. Composition according to Claim 1 or 2, characterized in that the epoxide having 3 to 8 carbon atoms consists in particular of epichlorohydrin, glycidol and its primary, secondary or tertiary methyl, ethyl, propyl, isopropyl, allyl and butyl ethers. , propylene oxide-1,2, styrene oxide, cyclohexene oxide and preferably butene oxide-1,2. 4. A composition according to any one of claims 1-3, characterized in that the amount of trioxane therein is between 0.5 and 3% by weight and that it is free of 2-methyl-3-butyn-2-ol. 5. A composition according to any one of claims 1-4, characterized in that the amine is preferably diisopropylamine, N-methylmorpholine or pyrrolidine. Composition according to any one of claims 1-5, characterized in that the antioxidant is preferably N-methylpyrrole.