HYDROFLUOROHALOCARBON DECOMPOSITION INHIBITOR AND METHOD

Abstract: A hydrochlorofluorocarbon (HCFC) decomposition inhibitor comprising at least one member selected from among a mixture of an organic acid with an amine, a fluorine-free halohydrocarbon, a carboxylic ester, a nitrile compound, a carbonyl compound and a halogenated nitro compound, and a method of inhibiting the decomposition of HCFC with the inhibitor. The inhibitor is effective in inhibiting for long the decomposition of HCFC used as a blowing agent in the production of polyurethane foam during the storage of the feedstock material, in the course of the production of the foam and during the use of the product.

Description: The present invention relates to a decomposition inhibitor for hydrogen- and fluorine-containing halogenated hydrocarbons and a method of inhibiting decomposition using the same. More particularly, the invention relates to a decomposition inhibitor capable of preventing hydrogen- and fluorine-containing halogenated hydrocarbons which are useful as blowing agents for foamed insulation materials (polyurethane foams) from decomposing during storage as raw materials for foamed insulation materials, during use as blowing agents (in the process of manufacturing foamed insulation materials) or during existence in the bubbles in products (foamed insulation materials) and relates to a method of using the same (for preventing hydrogen- and fluorine-containing halogenated hydrocarbons from decomposing). In the present specification, "%" and "part(s)" mean "% by weight" and "part(s) by weight", respectively. BACKGROUND ART Polyurethane foams, which are produced by using organic polyisocyanates and polyols as principal raw materials, are known as typical foamed insulation materials. Various blowing agents comprising "halogenated hydrocarbons with all the hydrogen atoms replaced by fluorine and chlorine" (hereinafter referred to as CFCs) have been proposed for use in the production of said polyurethane foams (cf. e.g. Japanese Kokai Tokkyo Koho JP 52-46005) and have been widely used on a large commercial scale. However, CFCs contained in such blowing agents are known to destroy the ozone layer and therefore restrictions have been imposed on the production and use thereof. Thus, the advent of novel blowing agents comparable in performance characteristics to CFCs and capable of serving as substitutes therefor has been awaited. For the time being, "hydrogen- and fluorine-containing halogenated hydrocarbons" (hereinafter referred to as HCFCs/HFCs) are regarded as promising since they involve no or little risk of depleting the ozone layer. Regrettably, however, HCFCs/HFCs are generally lacking in stability as compared with the conventional CFCs. It is known that they are particularly unstable when used in the form of a mixture with an alcoholic hydroxyl-containing compound. In addition, they are readily decomposable in the presence of water an alkali or a metal or under the action of light or heat, for instance. Methods have been proposed for preventing the decomposition of HCFCs/HFCs, for example by adding a nitro-containing hydrocarbon (Japanese Kokai Tokkyo Koho JP 01-128944) adding a nitro-containing hydrocarbon and an epoxide (Japanese Kokai Tokkyo Koho JP 01-128945), or adding other additives (see US 5 131 929 or WO 92/10453). The methods described in the above-cited patent specifications all aim to prevent the decomposition of such HCFCs/HFCs as mentioned above in an unstable state, for example in the presence of a polyol used as a raw material in the production of polyurethane foams. However, the known methods described in the above laid-open patent specifications cannot be said to be fully satisfactory in the effect of inhibiting the decomposition of HCFCs/HFCs. This is because HCFCs/HFCs gradually decompose not only during storage thereof but also in the process of polyurethane foam manufacture using HCFCs/HFCs and during a long period of use of polyurethane foam products manufactured by using HCFCs/HFCs (said HCFCs/HFCs thus occurring in the foam (bubbles)). Accordingly, there has been earnestly desired the advent of a novel method of preventing the decomposition of HCFCs/HFCs and thus keeping the HCFCs/HFCs stable under any of the condition mentioned above. DISCLOSURE OF THE INVENTION In view of the state of the art as mentioned above, the present inventors made intensive research and found the following: [A] (1) Mixtures of an organic acid and an amine, in particular mixtures of a carboxylic acid having an acid dissociation constant (pKa) of not more than 5 and a tertiary amine having an acid dissociation constant (pKa) of not more than 10; (2) fluorine-free halogenated hydrocarbons, in particular specific chlorinated hydrocarbons; (3) carboxylic acid esters, in particular condensates from a carboxylic acid having an acid dissociation constant (pKa) of not more than 5 and an alcohol containing 1 to 5 carbon atoms; (4) nitrile compounds, in particular nitrile compounds of the formula R 1 -CN wherein R 1 is an alkyl group containing 1 to 5 carbon atoms or a haloalkyl group containing 1 to 5 carbons; (5) carbonyl compounds, in particular carbonyl compounds of the formula wherein R 2 and R 3 are the same or different and each is an alkyl group containing 1 to 3 carbon atoms or a haloalkyl group containing 1 to 3 carbon atoms; and (6) halogenated nitro compounds, in particular halogenated nitro compounds of the formula R 4 -NO 2 wherein R 4 is a C 1-5 alkyl group substituted by at least one halogen atom or a phenyl group substituted by at least one halogen atom have excellent performance characteristics as decomposition inhibitors for HCFCs/HFCs, in particular for 1,1-dichloro-2,2,2-trifluoroethane, 1,1-dichloro-1-fluoroethane, 1,1,2,2,3-pentafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,2,2,3,3,4,4-octafluorobutane and 1,1,1,2-tetrafluoroethane; [B] When used in combination with an aliphatic or aromatic nitro compound, the above-mentioned compounds (1) to (6) are improved in the effect of preventing the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons (HCFCs/HFCs); [C] Furthermore, when these compounds are used as decomposition inhibitors, the decomposition inhibiting effect can be attained for a long period of time with HCFCs/HFCs in any circumstance, irrespective of the presence or absence of a polyol (i.e. an alcoholic hydroxyl-containing compound), namely in the presence of a polyol premixed therewith to give a raw material preparation for polyurethane foam manufacture (during storage), during the use as blowing agents in the production of polyurethane foams (in the step of foam manufacture) or during the occurrence in the bubbles in the polyurethane foam products (during use). Thus, the present invention provides a method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons which comprises using the decomposition inhibitor comprising at least one member of the class consisting of (a) a mixture of at least one organic acid selected from the group consisting of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, chlorobenzoic acid, aminobenzoic acid, nitrobenzoic acid, formic acid, citric acid, glutamic acid and oxalic acid and at least one amine selected from the group consisting of triethylenediamine, methylmorpholine, dimethylimidazole, dimethylaniline, methylpyrrole, pyridine, aminopyridine, methylpyridine and quinoline, (b) chlorohydrocarbon selected from the group consisting of 1-chloropropane, 2-chloropropane, 2-chloro-2-methylpropane and 1,1,1,2-tetrachloroethane, and (d) nitrile compound selected from the group consisting of monochloroacetonitrile, dichloroacetonitrile, trichloroacetonitrile, α-chloropropionitrile, β-chloropropionitrile, monobromoacetonitrile, α-bromopropionitrile and β-bromopropionitrile. In the organic acid-amine mixtures to serve as decomposition inhibitors for HCFCs/HFCs in accordance with the present invention, the organic acid is preferably a carboxylic acid having an acid dissociation constant (pKa) of not more than 5, for example a halogenated carboxylic acid such as monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid or chlorobenzoic acid, aminobenzoic acid, nitrobenzoic acid, formic acid, citric acid, glutamic acid, oxalic acid, etc. The amine is preferably a tertiary amine having an acid dissociation constant (pKa) of not more than 10, for example triethylenediamine, methylmorpholine, dimethylimidazole, dimethylaniline, methylpyrrole, pyridine, aminopyridine, methylpyridine, quinoline, etc. The organic acid and amine to be combinedly used and the proportions thereof can be arbitrarily selected according to the target HCFC or HFC, the other substances to be admixed therewith, the temperature conditions during storage, use (product manufacture) and use of foamed products, and other factors. Generally, however, preferable examples of the combination of an organic acid with an amine include combinations of monochloroacetic acid with dimethylimidazole, dimethylaniline or methylpyrrole. The combinations which are soluble in the HCFC/HFC are preferred. When such an organic acid-amine mixture is used singly as the decomposition inhibitor, said mixture is used generally in a proportion of 0.1 to 20%, preferably in a proportion of 1 to 10%, relative to the blowing agent. The fluorine-free halogenated hydrocarbons to serve as decomposition inhibitors for HCFCs/HFCs in accordance with the invention are, for example, 1,1-dichloroethane, 1,1,1-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, 1-chloropropane, 2-chloropropane, 1-chloro-2-methylpropane, 2-chloro-2-methylpropane, 1-chlorobutane, 2-chlorobutane, bromoethane, isopropyl bromide, n-propyl bromide, iodoethane, etc. Preferred among them are 1,1,1,2-tetrachloroethane, 2-chloro-2-methylpropane, 1-chloropropane and 2-chloropropane. When such a fluorine-free halogenated hydrocarbon is used singly as the decomposition inhibitor, the amount thereof can be arbitrarily selected according to the other substances to be mixed therewith, the temperature conditions during storage, use (product manufacture), and use of foamed products, and other factors. Generally, it is used in a proportion of 1 to 50%, preferably 5 to 30%, relative to the blowing agent. The nitrile compounds to serve as decomposition inhibitors in accordance with the present invention are preferably represented by the formula R 1 -CN wherein R 1 is an alkyl group containing 1 to 5 carbon atoms or a haloalkyl group containing 1 to 5 carbon atoms, and include, among others, acetonitrile, propionitrile, butyronitrile, valeronitrile, hexanonitrile, monochloroacetonitrile, dichloroacetonitrile, trichloroacetonitrile, α-chloropropionitrile, β-chloropropionitrile, monobromoacetonitrile, α-bromopropionitrile and β-bromopropionitrile. More preferred among these are those soluble in HCFCs/HFCs, such as monochloroacetonitrile, dichloroacetonitrile, trichloroacetonitrile, α-chloropropionitrile, β-chloropropionitrile, monobromoacetonitrile, α-bromopropionitrile, β-bromopropionitrile, etc. When such a nitrile compound is used singly as the decomposition inhibitor, it is used in an amount that can be arbitrarily selected according to the target HCFC or HFC, the other substances to be admixed therewith, the temperature conditions of storage, use, and use of foamed products, and other factors, generally in a proportion of 0.1 to 20%, preferably 1 to 10%, relative to HCFCs/HFCs. Further the invention provides a method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons which comprises using the decomposition inhibitor comprising at least one member of the class consisting of (c)monohalogenated acetic acid ester selected from the group consisting of methyl chloroacetate, ethyl chloroacetate, isopropyl chloroacetate, methyl bromoacetate and ethyl bromoacetate, and (f)monohalogenated nitro compound selected from the group consisting of monochloronitromethane, α-chloronitroethane, β-chloronitroethane, monobromonitromethane, α-bromonitroethane and β-bromonitroethane, wherein the hydrogen- and fluorine-containing halogenated hydrocarbon is 1,1-dichloro-2,2,2-trifluoroethane, 1,1-dichloro-1-fluoroethane, 1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,2,2,3,3,4,4-octafluorobutane or 1,1,1,2-tetrafluoroethane. When such a carboxylic acid ester is used singly as the decomposition inhibitor, its amount can be arbitrarily selected according to the other substances to be mixed therewith, the temperature conditions during storage, use (product manufacture), and use of foamed products, and other factors, generally in an amount of 0.1 to 20%, preferably 1 to 10%, relative to the blowing agent. When such a halogenated nitro compound is used singly as the decomposition inhibitor, it is used in an amount that can be arbitrarily selected according to the target HCFC or HFC the other substances to be admixed therewith, the temperature conditions of storage, use, and use of foamed products, and other factors, generally in an amount of 0.1 to 20%, preferably 1 to 20%, relative to HCFCs/HFCs. Further the invention provides a method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons which comprises using the decomposition inhibitor comprising at least one member of the class consisting of (e) halogenated carbonyl compound selected from the group consisting of 1-chloroacetone, 1,3-dichloroacetone, 1,1-dichloroacetone, 1-bromoacetone, 1,3-dibromoacetone, 1,1-dibromoacetone wherein the hydrogen- and fluorine-containing halogenated hydrocarbon 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,2,2,3,3,4,4-octafluorobutane or 1,1,1,2-tetrafluoroethane. When such a carbonyl compound is used singly as the decomposition inhibitor, it is used in an amount that can be arbitrarily selected according to the target HCFC or HFC the other substances to be admixed therewith, the temperature conditions of storage, use, and use of foamed products, and other factors, generally in a proportion of 0.1 to 20%, preferably 1 to 10%, relative to HCFCs/HFCs. In practicing the decomposition inhibiting method of the invention, any of the known conventional decomposition inhibitors can be used combinedly with the above-mentioned specific decomposition inhibitors characterizing the present invention, to stabilize HCFCs/HFCs against decomposition. As such known decomposition inhibitors, there may be mentioned, for example, the following: Nitro compounds other than halogenated nitro compounds, e.g. nitromethane, nitroethane, nitropropane, nitrobenzene, etc.; Aromatic hydrocarbons, e.g. styrene, methylstyrene (α-, β-, o-, m-, p-), p-isopropenyltoluene, p-diisopropenylbenzene, p-isopropenylxylene, divinylbenzene (m-, p-), 1,1-diphenylethylene, etc.; Unsaturated alicyclic hydrocarbons, e.g. cyclohexadiene, cyclopentadiene, α-pinene, α-limonene, furan, etc.; Unsaturated aliphatic hydrocarbons, e.g. isoprene, 2-methyl-2-butene, 2,3-dimethylbutadiene, 2,3-dimethyl-1-butene, 1,3-pentadiene, 1-hexene, myrcene, etc.; Epoxy compounds, e.g. 1,2-butylene oxide, isobutylene oxide, propylene oxide, epichlorohydrin, styrene oxide, glycidol, etc.; Ether compounds, e.g. 1,4-dioxane, 1,2-dimethoxyethane, phenyl glycidyl ether, allyl glycidyl ether, furan, 2,5-dihydrofuran, furil, acetylacetone, etc.; Phenol compounds, e.g. phenol, cresol (o-, m-, p-), methoxyphenol (o-, m-, p-), thymol, 2,6-di-tert-butyl-p-cresol, p-tert-butylphenol, eugenol, isoeugenol, anisole, isosafrole, p-tert-butylcatechol, etc.; Unsaturated alcohols, e.g. propargyl alcohol, 3-methyl-1-buten-3-ol, 2-methyl-3-butyn-3-ol, etc. The procedure for incorporating the decomposition inhibitor into compounds for polyurethane foam manufacture can suitably be selected. For instance, where a polyol and an organic isocyanate, which are principal components in compounds for polyurethane manufacture, are mixed and allowed to react with each other in the step of polyurethane foam formation, other additional components such as a blowing agent and are admixed with the polyol or organic isocyanate in advance. Therefore, it is possible to dissolve the decomposition inhibitor dissolved beforehand in the blowing agent and thus premix the inhibitor, together with the blowing agent, with the polylol or organic isocyanate, or to premix the decomposition inhibitor alone with the polyol or organic isocyanate. The means for mixing in each step can thus be selected arbitrarily. As examples of the HCFCs/HFCs that can be stabilized in accordance with the present invention, there may be mentioned the following: Hydrogen-containing chlorofluorohydrocarbons (HCFCs), e.g. monochlorodifluoromethane (HCFC 22; hereinafter the number alone is mentioned, as "22"), dichlorotrifluoroethane (123), monochlorotetrafluoroethane (124), dichloromonofluoroethane (141) and monochlorodifluoroethane (142); Hydrogen-containing fluorohydrocarbons (HFCs), e.g. difluoromethane (32), difluoroethane (152), trifluoroethane (143), tetrafluoroethene (134), heptafluoropropane (227), hexafluoropropane (236), pentafluoropropane (245), hexafluorobutane (356) and octafluorobutane (338). Where isomerism is possible for the HCFCs/HFCs mentioned above, the respective isomers may be used either singly or in the form of a mixture. It is to be noted that all such cases fall within the scope of the present invention. It is further to be noted that not only the single use of such HCFCs/HFCs as blowing agents but also the combined use thereof with other blowing agents or water falls within the scope of the present invention as well. As said other blowing agents that can be used in combination with HCFCs/HFCs in the decomposition inhibiting method of the invention, there may be mentioned, for example: Low-boiling halogenated hydrocarbons, e.g. trichloromonofluoromethane, dichlorodifluoromethane, methylene chloride, perfluoropentane, etc.; Low-boiling hydrocarbons, e.g. n-pentane, isopentane, cyclopentane, n-butane, isobutane, etc.; Inert gases, e.g. air, nitrogen, carbon dioxide, etc. As other raw materials to be used in manufacturing foamed insulation materials (polyurethane foams) by applying the present invention, there may be mentioned those well known in the art. Thus, the organic isocyanate, polyol, catalyst, foam controlling agent and other additives that are required for polyurethane foam formation may be as follows. The organic isocyanate may include those aliphatic, alicyclic or aromatic isocyanates that are described in the monograph "Keiji Iwata: Polyurethane Resin Handbook, pages 71-98, published by Nikkan Kogyo Shinbunsha", for instance. 2,4-Tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI) and mixtures of these (2,4-TDI/2,6-TDI ratio = 80/20 or 65/35, for instance) are polyisocyanates most generally used. Another typical example is polyphenylpolymethylene polyisocyanate (crude MDI) produced by reacting an aniline-formaldehyde condensate with phosgene. The polyol includes polyether polyols and polyester polyols (Keiji Iwata: Polyurethane Resin Handbook, pages 99-117, published by Nikkan Kogyo Shinbunsha). The polyether polyols can be produced by reacting an active hydrogen-containing initiator with an alkylene oxide. In the practice of the present invention, polyether polyols having 2 to 8 functional groups and a hydroxyl value of 300 to 600 mg KOH/g as produced by reacting such an initiator compound as ethylene glycol, trimethylolpropane, glycerol, triethanolamine, ethylenediamine, methyl glucoside, tolylenediamine, sorbitol and/or sucrose with such an alkylene oxide as ethylene oxide and/or propylene oxide can be used. The polyester polyols that can be used have 2 to 4 functional groups and a hydroxyl value of 250 to 500 mg KOH/g, including condensate polyester polyols produced by dehydration condensation of adipic acid and a glycol or triol, lactone polyesters produced by ring opening polymerization of caprolactone, and polycarbonate diols. Usable as the catalyst are tertiary amines, organometallic compounds, and mixtures of these. The catalyst is generally used in an amount of 0.01 to 10%, preferably about 0.1 to 5%, relative to the foam-forming mixture (organic isocyanate + polyol + blowing agent). As the tertiary amine, there may be mentioned monoamine such as triethylamine and dimethylcyclohexylamine, diamine such as tetramethylethylenediamine and tetramethylhexamethylenediamine, cyclic amines such as triethylenediamine and 1,2-dimethylimidazole, and alcohol amines such as dimethylaminoethanol, among others. As the organometallic compounds, there may be mentioned stannous octoate, dibutyl tin dilaurate, dibutyltin diacetate and lead octenoate. The foam controlling agent includes silicone surfactant and fluorine-containing surfactant, typically polysiloxane-polyalkylene block copolymers, methylpolysiloxane-based surfactant, etc. One or more of known additives such as fillers, colorants, fire retardants, antifungal agents and mold release agent may be incorporated where appropriate. Foamed insulation materials (polyurethane foams) can be produced by applying the present invention using the per se known methods of producing polyurethane foams without any particular modification. Thus, for instance, the method comprising reacting an organic polyisocyanate with an active hydrogen-containing compound, such as a polyol having at least two active-hydrogen-containing groups, in the presence of a catalyst and a blowing agent is well known for the production of polyurethane foams, and the established known processes include the one-shot process, prepolymer process and so forth. The present invention is effective in any of the methods and processes. EFFECTS OF THE INVENTION The decomposition inhibitors of the invention are excellent in the effect of inhibiting the decomposition of HCFCs/HFCs and, therefore, when foamed insulation materials (polyurethane foams) are produced using HCFCs/HFCs as blowing agents, said inhibitors can inhibit to a remarkable extent the decomposition of HCFCs/HFCs in any stage and in any state, namely not only during the raw material storage period preceding foam manufacture but also during the manufacture of foamed insulation materials (during the use of HCFCs/ HFCs as blowing agents ) and the use of foamed insulation materials (polyurethane foam products). The decomposition inhibiting method of the invention is very useful from the practical viewpoint as a method of inhibiting the decomposition of HCFCs/HFCs in particular when the HCFCs/HCFs are used as blowing agents in the manufacture of foamed insulation materials. EXAMPLES The following examples and comparative examples illustrate the invention in further detail. Examples 1 to 24 and Comparative Example 1 The materials used in the examples and comparative example were as follows: Polyol: o-Tolylenediamine-based polyether polyol with a hydroxyl value of 400 mg KOH/g; Foam controlling agent: Toray Silicone's silicone type foam controlling agent (trademark: "SH-193"); Catalyst: Tetramethylhexamethylenediamine; Blowing agent: 1,1-Dichloro-1-fluoroethane (HCFC141b); Decomposition inhibitors: A: Nitrobenzene; B: Monochloroacetic acid (1.9 g) + N-methylpyrrole (1.6 g); C: Monochloroacetic acid (1.9 g) + N,N-dimethylaniline (2.4 g); D: Monochloroacetic acid (1.9 g) + 1,2-dimethylimidazole (1.9 g): E: 1,1,1,2-Tetrachloroethane; F: 2-Chloro-2-methylpropane; G: 1-Chloropropane; H: Methyl chloroacetate; I: Ethyl chloroacetate; J: Methyl bromoacetate; K: Ethyl bromoacetate; L: Chloroacetonitrile; M: Bromoacetonitrile. Organic isocyanate: Polyphenylpolymethylenepolyisocyanate (crude MDI). A mixture for rigid polyurethane foam manufacture was prepared by mixing up the polyol (100 parts), foam controlling agent (1.5 parts), catalyst (3.4 parts) and blowing agent (30 parts), together with the decomposition inhibitor specified in Table 1 (in the proportion indicated). STABILIZER COMPOSITION PROPORTION〈PART(S)〉 COMPOSITION PROPORTION〈PART(S)〉 COMPARATIVE EXAMPLE 1 A 0.3 EXAMPLE 1 A 0.3 B 3.5 EXAMPLE 2 A 0.3 C 4.3 EXAMPLE 3 A 0.3 D 3.8 EXAMPLE 4 A 0.3 E 7.5 EXAMPLE 5 A 0.3 F 7.5 EXAMPLE 6 A 0.3 G 7.5 EXAMPLE 7 A 0.3 H 1.5 EXAMPLE 8 A 0.3 I 1.5 EXAMPLE 9 A 0.3 J 1.5 EXAMPLE 10 A 0.3 K 1.5 EXAMPLE 11 A 0.3 L 1.5 EXAMPLE 12 A 0.3 M 1.3 EXAMPLE 13 B 3.5 EXAMPLE 14 C 4.3 EXAMPLE 15 D 3.8 EXAMPLE 16 E 7.5 EXAMPLE 17 F 7.5 EXAMPLE 18 G 7.5 EXAMPLE 19 H 1.5 EXAMPLE 20 I 1.5 EXAMPLE 21 J 1.5 EXAMPLE 22 K 1.5 EXAMPLE 23 L 1.5 EXAMPLE 24 M 1.5 The organic isocyanate (71 parts) was added to the above mixture (100 parts). The whole mixture was made up into a polyurethane foam by the hand mixing technique and, after 1 day of maturation, the polyurethane foam was cut to cubes, 10 cm in edge size. The cubic pieces were vacuum-packed in laminated aluminum packs and then crushed using a press. The concentrations of decomposition gases 〈1-chloro-1-fluoroethylene (product A) and 1-chloro-1-fluoroethane (product B)〉 formed by the exothermic reaction were determined by gas chromatography for assessing the performance of the decomposition inhibitor in terms of the ability to inhibit the decomposition of the HCFC in the step of foam formation (during the reaction). The results obtained are shown in Table 2. Furthermore, the same vacuum-packed polyurethane foam pieces as those mentioned above were maintained at 90°C in a constant-temperature vessel for 2 weeks and the decomposition gas concentrations were then determined by gas chromatography to thereby assess the performance of the decomposition inhibitor in terms of the ability to inhibit the decomposition of the HCFC during aging. The results obtained are shown in Table 2. DECOMPOSITION GAS CONCENTRATION (ppm) DURING THE REACTION DURING AGING PRODUCT A PRODUCT B PRODUCT A PRODUCT B COMPATIVE EXAMPLE 1 100 20 10000 250 EXAMPLE 1 0 0 10 0 EXAMPLE 2 0 0 10 0 EXAMPLE 3 0 0 10 0 EXAMPLE 4 5 0 170 0 EXAMPLE 5 10 0 290 0 EXAMPLE 6 5 0 580 0 EXAMPLE 7 0 0 10 0 EXAMPLE 8 0 0 20 0 EXAMPLE 9 0 0 10 0 EXAMPLE 10 0 0 20 0 EXAMPLE 11 0 0 0 0 EXAMPLE 12 0 0 0 0 EXAMPLE 13 0 0 10 5 EXAMPLE 14 0 0 10 5 EXAMPLE 15 0 0 10 5 EXAMPLE 16 5 0 170 10 EXAMPLE 17 10 0 290 10 EXAMPLE 18 5 0 580 15 EXAMPLE 19 0 0 10 5 EXAMPLE 20 0 0 20 5 EXAMPLE 21 0 0 10 5 EXAMPLE 22 0 0 20 5 EXAMPLE 23 0 0 10 10 EXAMPLE 24 0 0 10 15 Examples 25 to 48 and Comparative Example 2 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that 1,1-dichloro-2,2,2-trifluoroethane (HCFC123) was used as the blowing agent. The stabilizers and proportions thereof used in the examples and comparative example are shown in Table 3. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HCFC during reaction and during aging are shown in Table 4. The concentrations of 1,1-dichloro-2,2-difluoroethylene (product C) and 1-chloro-2,2,2-trifluoroethane (product D) were determined as the decomposition gas concentrations. STABILIZER COMPOSITION PROPORTION〈PART(S)〉 COMPOSITION PROPORTION〈PART(S)〉 COMPARATIVE EXAMPLE 2 A 0.3 EXAMPLE 25 A 0.3 B 3.5 EXAMPLE 26 A 0.3 C 4.3 EXAMPLE 27 A 0.3 D 3.8 EXAMPLE 28 A 0.3 E 7.5 EXAMPLE 29 A 0.3 F 7.5 EXAMPLE 30 A 0.3 G 7.5 EXAMPLE 31 A 0.3 H 1.5 EXAMPLE 32 A 0.3 I 1.5 EXAMPLE 33 A 0.3 J 1.5 EXAMPLE 34 A 0.3 K 1.5 EXAMPLE 35 A 0.3 L 1.5 EXAMPLE 36 A 0.3 M 1.3 EXAMPLE 37 B 3.5 EXAMPLE 38 C 4.3 EXAMPLE 39 D 3.8 EXAMPLE 40 E 7.5 EXAMPLE 41 F 7.5 EXAMPLE 42 G 7.5 EXAMPLE 43 H 1.5 EXAMPLE 44 I 1.5 EXAMPLE 45 J 1.5 EXAMPLE 46 K 1.5 EXAMPLE 47 L 1.5 EXAMPLE 48 M 1.5 DECOMPOSITION GAS CONCENTRATION (ppm) DURING THE REACTION DURING AGING PRODUCT C PRODUCT D PRODUCT C PRODUCT D COMPATIVE EXAMPLE 2 50 960 100 4800 EXAMPLE 25 0 0 0 30 EXAMPLE 26 0 0 0 20 EXAMPLE 27 0 0 0 30 EXAMPLE 28 0 0 5 30 EXAMPLE 29 0 0 10 40 EXAMPLE 30 0 0 5 20 EXAMPLE 31 0 0 0 50 EXAMPLE 32 0 0 0 70 EXAMPLE 33 0 0 0 60 EXAMPLE 34 0 0 10 80 EXAMPLE 35 0 20 0 130 EXAMPLE 36 0 30 0 150 EXAMPLE 37 0 10 0 50 EXAMPLE 38 0 5 0 35 EXAMPLE 39 0 10 0 50 EXAMPLE 40 0 10 5 50 EXAMPLE 41 0 15 10 65 EXAMPLE 42 0 10 5 40 EXAMPLE 43 0 10 0 70 EXAMPLE 44 0 5 0 85 EXAMPLE 45 0 10 0 80 EXAMPLE 46 0 10 10 100 EXAMPLE 47 0 20 0 130 EXAMPLE 48 0 30 0 150 Examples 49 to 62, 77 and 78 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that the decomposition inhibitors specifically shown in Table 5 (with the proportions thereof) were used as the stabilizers. The symbols (N, O, P, Q, R, S, T and U) used in Table 5 to identify the decomposition inhibitors respectively correspondent the following compounds: N: β-Chloropropionitrile; O: 1-Chloroacetone; P: 1-Bromoacetone; Q: 1,1-Dichloroacetone; R: Chloronitromethane; S: Bromonitromethane; T: β-Chloronitroethane; U: Isopropyl chloroacetate. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HCFC during reaction and during aging are shown in Table 6, together with the data for Comparative Example 1 mentioned hereinbefore. STABILIZER COMPOSITION PROPORTION〈PART(S)〉 COMPOSITION PROPORTION〈PART(S)〉 COMPARATIVE EXAMPLE 1 A 0.3 EXAMPLE 49 A 0.3 N 1.5 EXAMPLE 53 A 0.3 R 1.5 EXAMPLE 54 A 0.3 S 1.5 EXAMPLE 55 A 0.3 T 1.5 EXAMPLE 56 N 1.5 EXAMPLE 60 R 1.5 EXAMPLE 61 S 1.5 EXAMPLE 62 T 1.5 EXAMPLE 77 A 0.3 U 1.5 EXAMPLE 78 U 1.5 DECOMPOSITION GAS CONCENTRATION (ppm) DURING THE REACTION DURING AGING PRODUCT A PRODUCT B PRODUCT A PRODUCT B COMPARATIVE EXAMPLE 1 100 20 10000 250 EXAMPLE 49 0 0 10 0 EXAMPLE 53 0 0 20 0 EXAMPLE 54 0 0 20 0 EXAMPLE 55 0 0 15 0 EXAMPLE 56 0 0 10 5 EXAMPLE 60 0 0 20 10 EXAMPLE 61 0 0 20 10 EXAMPLE 62 0 0 15 5 EXAMPLE 77 0 0 15 0 EXAMPLE 78 0 0 20 15 Examples 63 to 76, 79 and 80 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that HCFC 123 was used as the blowing agent and the decomposition inhibitors specified, together with the proportions, in Table 7 were used as the stabilizers. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HCFC during reaction and during aging are shown in Table 8, together with the data for Comparative Example 2 mentioned hereinabove. The concentrations of 1,1-dichloro-2,2-difluoroethylene (product C) and 1-chloro-2,2,2-trifluoroethane (product D) were determined as the decomposition gas concentrations. STABILIZER COMPOSITION PROPORTION〈PART(S)〉 COMPOSITION PROPORTION〈PART(S)〉 COMPARATIVE EXAMPLE 2 A 0.3 EXAMPLE 63 A 0.3 N 1.5 EXAMPLE 67 A 0.3 R 1.5 EXAMPLE 68 A 0.3 S 1.5 EXAMPLE 69 A 0.3 T 1.5 EXAMPLE 70 N 1.5 EXAMPLE 74 R 1.5 EXAMPLE 75 S 1.5 EXAMPLE 76 T 1.5 EXAMPLE 79 A 0.3 U 1.5 EXAMPLE 80 U 1.5 DECOMPOSITION GAS CONCENTRATION (ppm) DURING THE REACTION DURING AGING PRODUCT C PRODUCT D PRODUCT C PRODUCT D COMPARATIVE EXAMPLE 2 50 960 100 4800 EXAMPLE 63 0 10 0 100 EXAMPLE 67 0 20 0 130 EXAMPLE 68 0 20 5 120 EXAMPLE 69 0 15 0 100 EXAMPLE 70 0 15 0 105 EXAMPLE 74 0 20 0 140 EXAMPLE 75 0 20 5 130 EXAMPLE 76 0 15 0 120 EXAMPLE 79 0 10 0 100 EXAMPLE 80 0 10 0 150 Examples 81 to 120 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that 1,1,1,3,3-pentafluoropropane (HFC 245fa) was used as the blowing agent. The stabilizers and proportions thereof used in the respective examples and comparative example are shown in Table 9. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HFC during reaction and during aging are shown in Table 10. The concentration of 1,3,3,3-tetrafluoropropene (product E) was determined as the decomposition gas concentration. Examples 121 to 160 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that 1,1,2,2,3-pentafluoropropane (HFC 245ca) was used as the blowing agent. The stabilizers and proportions thereof used in the respective examples and comparative example are shown in Table 11. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HFC during reaction and during aging are shown in Table 12. The concentration of 1,3,3,3-tetrafluoropropene (product F) was determined as the decomposition gas concentration. Examples 161 to 200 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that 1,1,1,4,4,4-hexafluorobutane (HFC 365nff) was used as the blowing agent. The stabilizers and proportions thereof used in the respective examples and comparative example are shown in Table 13. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HFC during reaction and during aging are shown in Table 14. The concentration of 1,1,4,4,4-pentafluorobutene (product G) was determined as the decomposition gas concentration. Examples 201 to 240 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that 1,1,2,2,3,3,4,4-octafluorobutane (HFC 338pcc) was used as the blowing agent. The stabilizers and proportions thereof used in the respective examples and comparative example are shown in Table 15. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HFC during reaction and during aging are shown in Table 16. The concentration of 1,1,2,3,3,4,4-heptafluoro-1-butene (product H) was determined as the decomposition gas concentration. Examples 241 to 280 Polyurethane foams were produced in the same manner as in Examples 1 to 24 and Comparative Example 1 except that 1,1,1,2-tetrafluoroethane (HFC 134a) was used as the blowing agent. The stabilizers and proportions thereof used in the respective examples and comparative example are shown in Table 17. The performance characteristics of each stabilizer as evaluated in the same manner as in Examples 1 to 24 and Comparative Example 1 and expressed in terms of the ability to inhibit the decomposition of the HFC during reaction and during aging are shown in Table 18. The concentration of 1,1,2-trifluoroethylene (product I) was determined as the decomposition gas concentration.

Claims: A method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons which comprises using the decomposition inhibitor comprising at least one member of the class consisting of (a) a mixture of at least one organic acid selected from the group consisting of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, chlorobenzoic acid, aminobenzoic acid, nitrobenzoic acid, formic acid, citric acid, glutamic acid and oxalic acid and at least one amine selected from the group consisting of triethylenediamine, methylmorpholine, dimethylimidazole, dimethylaniline, methylpyrrole, pyridine, aminopyridine, methylpyridine and quinoline, (b) chlorohydrocarbon selected from the group consisting of 1-chloropropane, 2-chloropropane, 2-chloro-2-methylpropane and 1,1,1,2-tetrachloroethane, and (d) nitrile compound selected from the group consisting of monochloroacetonitrile, dichloroacetonitrile, trichloroacetonitrile, α-chloropropionitrile, β-chloropropionitrile, monobromoacetonitrile, α-bromopropionitrile and β-bromopropionitrile. A method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons as defined in Claim 1 wherein the hydrogen- and fluorine-containing halogenated hydrocarbon is 1,1-dichloro-2,2,2-trifluoroethane, 1,1-dichloro-1-fluoroethane, 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,2,2,3,3,4,4-octafluorobutane or 1,1,1,2-tetrafluoroethane. A method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons which comprises using the decomposition inhibitor comprising at least one member of the class consisting of (c) monohalogenated acetic acid ester selected from the group consisting of methyl chloroacetate, ethyl chloroacetate, isopropyl chloroacetate, methyl bromoacetate and ethyl bromoacetate, and (f) monohalogenated nitro compound selected from the group consisting of monochloronitromethane, α-chloronitroethane, β-chloronitroethane, monobromonitromethane, α-bromonitroethane and β-bromonitroethane, wherein the hydrogen- and fluorine-containing halogenated hydrocarbon is 1,1-dichloro-2,2,2-trifluoroethane, 1,1-dichloro-1-fluoroethane, 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,2,2,3,3,4,4-octafluorobutane or, 1,1,1,2-tetrafluoroethane. A method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons which comprises using the decomposition inhibitor comprising at least one member of the class consisting of (e) halogenated carbonyl compound selected from the group consisting of 1-chloroacetone, 1,3-dichloroacetone, 1,1-dichloroacetone, 1-bromoacetone, 1,3-dibromoacetone and 1,1-dibromoacetone wherein the hydrogen- and fluorine-containing halogenated hydrocarbon is 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3-pentafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,2,2,3,3,4,4-octafluorobutane or 1,1,1,2-tetrafluoroethane. A method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons as defined in one of Claim 1 to 4 which comprises using the decomposition inhibitor further comprising an aliphatic or aromatic nitro compound. A method of inhibiting the decomposition of hydrogen- and fluorine-containing halogenated hydrocarbons as defined in claim 5 which comprises using the decomposition inhibitor comprising at least one aliphatic or aromatic nitro compound selected from the group consisting of nitromethane, nitroethane, nitropropane and nitrobenzene.

Inventors: AOYAMA HIROKAZU, IDE SATOSHI, INABA TSUYOSHI, MAEKAWA NAOKI, TSUCHIYA TATSUMI, AOYAMA, HIROKAZU,, IDE, SATOSHI,, INABA, TSUYOSHI,, MAEKAWA, NAOKI,, TSUCHIYA, TATSUMI,, AOYAMA, HIROKAZU, YODOGAWA SEISAKUSHO, IDE, SATOSHI, YODOGAWA SEISAKUSHO, INABA, TSUYOSHI, YODOGAWA SEISAKUSHO, MAEKAWA, NAOKI, YODOGAWA SEISAKUSHO, TSUCHIYA, TATSUMI, YODOGAWA SEISAKUSHO
Applicants: DAIKIN IND LTD, DAIKIN INDUSTRIES, LIMITED
Application year: 1993
Main classification: C07C19
IPC codes: C08J9, C07C17