Phosphite compounds

Abstract: Phosphite compounds represented by the formula wherein R¹ stands for a tertiary hydrocarbyl group, R² stands for an alkyl group, an aralkyl group which may be substituted, an aryl group or a cycloalkyl group and n stands for 0, 1 or 2. Such compounds possess stabilizing action against organic materials, particularly antioxidant action, and are useful as antioxidants for preventing deterioration by oxidation of organic materials.

Description: BACKGROUND OF THE INVENTION This invention relates to novel phosphite compounds which are useful as stabilizing agents for organic materials. Since organic materials which consist of natural macromolecule, synthetic macromolecule, fats and oils, lubricants, working oil or so on are subject to oxidation and decrease in utility, various antioxidants have been devised and have been added to these organic materials. It is known that stabilizers such as hindered phenol, organic sulfur compounds, organic phosphorus compounds and aromatic amines have stabilizing effects when used singly or in combination. The above-mentioned stabilizing agents have their respective merits and are useful. In particular, phosphite compounds of organic phosphorus compounds are widely used as useful antioxidants. As concrete examples of phosphite compounds, there have been known the compounds which are described in the gazettes of Japanese Patent Application Examined Publication (Kokoku) No. 1641/1958 and Japanese Patent Application Unexamined Publication (Kokai) No. 4629/1984. As concrete examples of attempt for stabilizing effects with the combined use of phosphite compounds and hindered phenol compounds, there have been proposed such combined use in the gazette of Japanese Patent Application Examined Publication No. 12373/1962 in the specification of U.S. Patent No. 3558554, in the gazette of Japanese Patent Application Unexamined Publication No. 109050/1976 and in the gazette of Japanese Patent Application Examined Publication No. 21822/1987. However, the above-mentioned phosphite compounds hitherto known include various problems, and satisfactory phosphite compounds have not been known so far. Specifically, the above-mentioned known phosphite compounds have include, among others, the problem that since the phosphite compounds are susceptible to hydrolysis and thermal decomposition, sufficient stabilizing effect can not be desired and inconveniences such as corrosion and foul-smelling are apt to occur. Phosphite compounds having sterically bulky structure in the neighbourhood of the phosphite bond involve the problem that they are difficult to synthesize. For example, in the case where tris(2,4,6-trisubstituted phenyl)phosphites have a bulky group such as tert-butyl group as the substituents at the 2- and 6- positions, they are difficult to synthesize and industrially less valuable. SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to provide phosphite compounds which are easy to synthesize, scarcely decompose and exhibit high stabilizing effects. Another object of the present invention is to provide stabilizing agents for organic materials comprising the novel phosphite compounds. DETAILED DESCRIPTION Said object can be attained according to the present invention, that is, the phosphite compound represented by the formula wherein R¹ stands for a tertiary butyl group, R² stands for a straight or branched alkyl group having 1 to 22 carbon atoms or phenyl and n stands for 2 [hereinafter referred to as compound (I)]. As the straight- or branched-alkyl groups having 1 to 22 carbon atoms mention is made of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, isohexyl, 1-methylpentyl, heptyl, octyl, 2-ethylhexyl, 1,1,3,3-tetramethylbutyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl and docosyl. The phenyl group may have substituent(s). As substituent of the phenyl group there are mentioned alkyl groups and phenyl. As the alkyl group as the substituent, mention is made of straight- and branched-alkyl groups having 1 to 4 carbon atoms (e.g. methyl, ethyl, propyl, isopropyl, butyl). The phenyl group may have 1 to 3 said substituents on the aromatic ring. The compounds of the formula (I) of the present invention have the following characteristics: Firstly, it is essentially critical that in the formula (I), the substituent at the 4-position of the phenyl nucleus is not a simple alkyl group such as methyl group, ethyl group, propyl group, butyl group, octyl group, nonyl group or dodecyl, but a group of the formula -(CH₂) n -COOR². That is, the structure of the substituent at the 4-position is not particularlly restrictive in the synthesis of the compound (I). Besides, the substituent is an important factor to impart necessary properties as a stabilizing agent such as solubility to organic compounds or organic materials to be stabilized, polymerlzation of the compound (I) and decomposition-resistance. Secondly, it is significantly meaningful that the compounds (I) have no substituent at the 6-position. That is, the compounds substituted by sterically bulky group such as tert-butyl group at the 6-position, which are difficult to synthesize, are substantially distinguishable from the compounds (I). As the concrete examples of the compound (I), the following can be mentioned. Tris[2-tert-butyl-4-(2-(methoxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(butoxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(2-ethylhexyloxycarbonyl)ethyl)phenyl)phosphite Tris[2-tert-butyl-4-(2-dodecyloxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(tridecyloxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(octadecyloxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(docosyloxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(phenoxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(3-methylphenoxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(4-tert-butylphenoxycarbonyl)ethyl)phenyl]phosphite Tris[2-tert-butyl-4-(2-(2,6-dimethylphenoxycarbonyl)ethyl)phenyl]phosphite The compounds (I) can be produced by reacting the compound of the formula wherein each symbol is of the same meaning as defined above [hereinafter referred to as compound (II)] with the compound of the formula P-X₃ (III) wherein X stands for a halogen atom [hereinafter referred to as compound (III)] or the compound of the formula P-(OR⁵)₃ (IV) wherein R⁵ stands for an alkyl or an aryl [hereinafter referred to as compound (IV)]. The reaction of the compound (II) with the compound (III) usually proceeds in a solvent such as benzene, toluene, hexane, heptane, diethyl ether, tetrahydrofuran, chloroform, carbon tetrachloride, dichloroethane, chlorotoluene or chlorobenzene in the presence of an amine such as pyridine, dimethylformamide, triethylamine, dimethylaniline and diethylaniline under cooling or at a temperature ranging from room temperature to the boiling point of the used solvent for 30 minutes to 24 hours. The reaction of the compound (II) with the compound (IV) usually proceeds in the presence of a base such as sodium hydroxide, potassium hydroxide or sodium methoxide in a solvent such as toluene, benzene, hexane, heptane, chlorotoluene or chlorobenzene at a temperature ranging from room temperature to 200°C for 1 hour to 24 hours. The obtained objective compound (I) can be purified by a conventional means such as recrystallization and chromatography. The compound (II) can be produced by reacting the compound of the formula wherein each symbol is of the same definition as mentioned above [hereinafter referred to as compound (V)] with the compound of the formula R²-OH (VI) wherein R² is as defined above [hereinafter referred to as compound (VI)] or by subjecting the compound of the formula wherein R³ is methyl or ethyl and R¹ and n are as defined above [hereinafter referred to as compound (VII)] which can be obtained by the above-mentioned reaction with the use of the compound of the formula (VI) wherein R² is methyl or ethyl, with the compound of the formula R⁴-OH (VIII) wherein R⁴ is the same group as R² excluding methyl and ethyl [hereinafter referred to as compound (VIII)] to ester interchange reaction. Also, the compound (II) can be produced by conducting elimination reaction for the tert-hydrocarbyl group of the compound of the formula wherein R⁵ stands for a tert-butyl group and the other symbols are as defined above [hereinafter referred to as compound (IX)] in the presence of an acidic substance. The esterification reaction of the compound (V) with the compound (VI) usually proceeds in the presence of an acid such as hydrochloric acid, sulfuric acid, perchloric acid or p-toluenesulfonic acid, a base such as sodium hydroxide, potassium hydroxide, sodium methoxide, a tin compound such as monobutyltin oxide, dibutyltin oxide, monobutyltin chloride or a phosphorus halide compound such as phosphorus trichloride or phosphorus oxychloride in a solvent such as benzene, toluene, hexane or heptane at a temperature ranging from room temperature to 200°C for 1 hour to 24 hours. The ester interchange reaction of the compound (VII) with the compound (VIII) usually proceeds under the same conditions as the above-mentioned esterification reaction. As the acidic substance usable for the elimination reaction of the tert-butyl group of the compound (IX), there can be mentioned inorganic acids such as sulfuric acid, hydrochloric acid and perchloric acid and organic acids such as trifluoroacetic acid, benzenesulfonic acid and p-toluenesulfonic acid. The reaction proceeds in a solvent such as dichloroethane, chloroform, benzene or toluene under cooling or at a temperature ranging from room temperature to the boiling point of the used solvent for 30 minutes to 24 hours. The compounds (I) of the present invention possess stabilizing action against organic materials, particularly antioxidant action, and are useful as antioxidants for preventing deterioration by oxidation of organic materials being macromolecular polymers, fats and oils, mineral oils themselves and those represented thereby. As the macromolecular polymers, mention can be made of polyolefin polymers or copolymers thereof such as α-olefin polymers or methylene-vinyl acetate co-polymers and methylene-propylene copolymers exemplified by polyethylene, polypropylene, polybutene, poly-3-methylbutylene, halogen-containing synthetic resins such as poly(vinyl chloride), poly(vinyl fluoride), poly(vinylidene fluoride), poly(brominated ethylene), chlorinated rubber, vinyl chloride-vinyl acetate copolymers, vinyl chloride-methylene copolymers, vinyl chloride-propylene copolymers, vinyl chloride-styrene copolymers, vinyl chloride-isobutylene copolymers, vinyl chloride-vinylidene chloride copolymers, vinyl chloride-styrene-maleic acid anhydride terpolymers, vinyl chloride-styrene-acrylonitrile copolymers, vinyl chloride-butadiene copolymers, vinyl chloride-isobutylene copolymers, vinyl chloride-propylene chloride copolymers, vinyl chloride-isopropylene copolymers, vinyl chloride-vinylidene chloride-vinyl acetate terpolymers, vinyl chloride-acrylate copolymers, vinyl chloride-malerate copolymers, vinyl chloride-methacrylate, vinyl chloride-acrylonitrile copolymers and internal plastic polyvinyl chlorides, petroleum resins, cumarone resins, polystyrenes, poly(vinyl acetate), acryl resins, copolymers of styrene with other monomers (maleic anhydride, butadiene, acrylonitrile and the like), acrylonitrile-butadiene-stylene copolymers, acrylate-butadiene-styrene copolymers, methacrylate-butadiene-styrene copolymers, methacrylate resins such as poly(methyl methacrylate), poly(vinyl alcohol), poly(vinyl formal), poly(vinyl butyral), straight-chain polyesters, polyphenyleneoxide, polyamides, polycarbonates, polyacetals, polyurethanes, fiber-resins, unsaturated polyester resins, phenol resins, urea resins, melamine resins, epoxy resins, silicone resins, polyethylene terephthalate, polyphenylenesulfide, polybutylene terephthalate, polysulfone resins, polyethersulfone, polyetheretherketone, polyarylate, polyetherimide, polyetherimide, polyimides, maleimide and polyamideimide. Further, there are included rubbers such as natural rubbers, isoprene rubbers, butadiene rubbers, acrylonitrile-butadiene copolymer rubbers and blend of the above-mentioned resins. In case where the compounds (I) of the present invention are used as stabilizing agents for organic materials, they are used preferably together with hindered phenol compounds. As the hindered phenol compounds, there may be mentioned 2,6-di-tert-butyl-4-methylphenol, 4-hydroxymethyl-2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-ethylphenol, butylhydroxyanisole, octadecyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate, distearyl (4-hydroxy-3-methyl-5-tert-butyl)benzylmalonate, propyl gallate, octyl gallate, dodecyl gallate, tocopherol, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4-methylenebis(2,6-di-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), styrene phenol, N,N'-hexamethylene-bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), 3,5-di-tert-butylhydroxybenzylphosphonic acid aminoethyl ester calcium, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane, 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-dihydroxy-3,3'-dicyclohexyl-5,5'-dimethylphenylmethane, 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6(1H,3H,5H)trione, triethyleneglycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], 2,2'-oxamide bis[ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 6-(4-hydroxy-3,5-di-tert-butylanilino)-2,4-dioctylthio-1,3,5-triazine, bis[2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl]terephthalate, 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetra- oxaspiro[5.5]undecane and 3,9-bis[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane and 3,9-bis[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane acid. When the compounds (I) of the present invention are used as antioxidant for organic materials, they are added to the organic materials preferably in a proportion of 0.01 to 5 weight % relative to the organic materials. When at least one of the compounds (I) is used in combination with at least one of hindered phenol compounds as the stabilizing agents, it can be incorporated into organic materials preferably in a proportion of 0.01 to 5 weight % relative to the organic materials, and the ratio of the compound (I) and the hindered phenol compounds may range from 10:1 to 1:5, preferably from 5:1 to 1:2. The compound (I) of the present invention is singly or in combination with a hindered phenol compound incorporated into organic materials by a method of mixing followed by treatment by processes such as kneading and extrusion. A thioalkanoate compound selected from the group consisting of dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate and pentaerythritol tetrakis(β-laurylthiopropionate) can also be used together with the compounds of the present invention. When the compound (I) of the present invention is used as stabilizing agents for organic materials, it can be used further in combination with salycylic acid, benzophenone, benzotriazole, cyanoacrylate, piperidine and nickel compound-light stabilizing agents exemplified by phenyl salycylate, p-tert-butyl salycylate, p-octylphenyl salycylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxyethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-isooctyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, di-sodium 2-hydroxy-4-octadecyloxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfobenzophenone, 2-hydroxy-4-(2-hydroxy-3-methacryloxy)propoxybenzophenone, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate, ethyl 2-cyano-3,5-diphenylacrylate, nickel[2,2-thiobis(4-tert-octylphenolate)]-n-butylamine, nickel bis(octylphenylsulfide), nickel bis[o-ethyl(3,5-di-tert-butyl-4-hydroxybenzyl)]phosphonate, bis(2,2,6,6-tetramethyl-4-piperidine)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, poly{(6-(1,1,3,3-tetramethyl-4-piperidyl)amino]-s-triazine-2,4-diyl}, [(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino], poly(6-morpholino-s-triazine-2,4-diyl)[(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino], 1-hydroxyethyl-2,2,6,6-tetramethyl-4-piperidinol/succinic acid condensate, cyanulic chloride/tert-octylamine/1,6-bis(2,2,6,6-tetrmethyl-4-piperidylamino)hexane condensate, or metal soaps, heavy metal inactivating agents, nucleator, organic tin compounds, plasticizers, epoxy compounds, pigments, fillers, a foaming agents, anti-electrifying agents, flame-retardants, lubricants and process auxiliaries. Hitherafter, the antioxidant effects of the compounds of the present invention are shown by the experimental examples. Experimental Example 1 To polypropylene powders 98% of which are isotactic ones having an intrinsic viscosity of 1.9 when measured in tetralin at 135°C was added an antioxidant, and the mixture was well mixed in a mixer. The mixture was melted and kneaded with the extruder of a diameter of 20 mm with a ratio of L/D of 20 at a cylynder temperature of 260°C to be granulated. The MFR (JIS K6758) at 230°C of the thus obtained pellets was measured and taken as MFR₁. Further, the mixture was subjected to the extruder three times repeatedly under the above-mentioned conditions as regards kneading and granulation. The MFR at 230°C of the thus obtained pellets was taken as MFR₄. MFR is one of indexes for molecular weight. The higher MFR is, the smaller the molecular weight is. That is, if MFR, and MFR₄ are lower and the balance of MFR₁ and MFR₄ is small, it is meant that small is the decrease in molecular weight owing to oxidation and deterioration in the extruder. When the antioxidants are used, it is meant that the antioxidant effects thereof are great. Antioxidant MFR₁ MFR₄ Comparative example none 12.3 not less than 50 " 3,9-Bis(octadecyloxy)-2,4, 8,10-tetraoxa-3,9-phosphaspiro[5.5]undecane 0.1PHR 8.5 40 Example of the present invention Tris[2-tert-butyl-4-(2-octadecyloxycarbonyl)ethylphenyl]phosphite 0.1PHR 7.0 27 Comparative example Tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane 0.1PHR 5.2 11.7 3,9-Bis(octadexyloxy)-2,4, 8,10-tetraoxa-3,9-phosphaspiro[5.5]undecane 0.1PHR Example of the present invention Tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane 0.1PHR 3.5 4.2 Application example Tris[2-tert-butyl-4-(2-(octadecyloxycarbonyl)ethyl) phenyl]phosphite 0.1PHR Experimental Example 2 Representative phosphite compounds hitherto known and the compounds (I) of the present invention are examined for their heat resistance, and the results were shown in Fig. 1 for the comparison of their heat resistance. In Fig. 1, the compounds a, b and c mean the following compounds respectively. Compound a: Tris(2,4-di-tert-butylphenyl)phosphite(hitherto-known compound) Compound b: 3,9-Bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-phosphaspiro[5,5]undecane (hitherto-known compound) Compound c: Tris[2-tert-butyl-4-(2-(octadecyloxycarbonyl)ethyl) phenyl]phosphite [The compound (I) of this invention] The equipment used for this experiment was thermofrec 8100 type manufactured by Rigaku. The behaviours in weight-decrease of the compounds were measured. Below, the present invention is in detail explained by reference examples and working examples, which are not to be construed as limitative. The obtained compounds were as certained respectively as the objective compounds (I) by such means as infrared absorption spectrum, nuclear magnetic resonance spectrum, mass spectrum and elemental analysis. Reference Example (Production Example of Starting Compounds) (1) A mixture of 45 g of methyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate, 24.7 g of 2-ethylhexylalcohol, 0.5 g of dibutyltin oxide and 50 ml of toluene was heated to 140°C, whereto toluene was further added while the solvent was being distilled off. After the mixture was stirred for 10 hours, toluene was distilled off. The obtained residue was purified by silica gel column chromatography to give 60 g of 2-ethylhexyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a pale yellow oily substance. By using dodecyl alcohol, tridecyl alcohol, octadecyl alcohol or docosyl alcohol instead of 2-ethylhexyl alcohol, the same reaction and treatment as the above-mentioned was conducted to give the following compounds. Dodecyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a pale yellow oily substance; Tridecyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a pale yellow oily substance; Octadecyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a white crystal, m.p. 43 - 45°C; Docosyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a white crystal, m.p. 44 - 47°C; (2) A mixture of 55 g of 3-(3-tert-butyl-4-hydroxyphenyl)propionic acid, 35 g of phenol, 7 g of dimethylformamide, 19.1 g of phosphorus oxychloride and 250 ml of toluene was stirred at 70°C for 6 hours. The mixture was cooled to room temperature, and 800 ml of toluene was added thereto. The mixture was washed with water and an aqueous solution of sodium hydroxide, followed by washing with water. The mixture was concentrated, and the residue was purified by silica gel column chromatography to give 66.5 g of phenyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a white crystal, m.p. 106 - 109°C. By using 3-methylphenol, 4-tert-butylphenol or 2,6-dimethylphenol instead of phenol, the same reaction and treatment as mentioned above was conducted to give the following compounds. 3-Methylphenyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a white crystal, m.p. 96 - 98°C. 4-Tert-butylphenyl 3-(3-tertbutyl-4-hydroxyphenyl)propionate as a white crystal, m.p. 104 - 106°C. 2,6-Dimethylphenyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as a white crystal, m.p. 101 - 104°C. (3) A mixture of 50 g of methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2.5 g of conc. hydrochloric acid and 30 ml of toluene was refluxed for 2 hours while stirring. After the completion of the reaction, the reaction mixture was washed with water and the solvent was distilled off. Hexane was added to the residue and the mixture was ice-cooled. The resulting crystals were collected by filtration and recrystallized from hexane to give 29 g of methyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate as white crystals, m.p. 59 - 61°C. Example 1 To a solution of 23.6 g of methyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate, 0.47 g of pyridine and 60 ml of toluene was added dropwise 4.5 g of phosphorus trichloride at 70°C, and the mixture was heated, and refluxed while stirring for 6 hours. After the completion of the reaction, the reaction mixture was cooled to room temperature. Thereto were added 30 ml of water and 40 ml of toluene, and the mixture was washed with water. The mixture was subjected to separation. The toluene layer was concentrated and purified by silica gel column chromatography to give 63 g of tris[2-tert-butyl-4-(2-(methoxycarbonyl)ethyl)phenyl]phosphite as a pale yellow oily substance. Elemental Analysis C (%) H (%) P (%) Calcd. 68.45, 7.79, 4.2 Found 68.55, 7.73, 4.15 IR (cm⁻¹) ν P-O 850, 1190 ; ν C=O 17.35 (Film) NMR (CDCl₃) δ 1.20 - 1.40 (m, 27H), 2.50 - 3.0 (m, 12H), 3.63 (s, 9H), 6.80 - 7.30 (m, 9H) Examples 2 - 8 By using the corresponding 2-ethylhexyl ester, tridecyl ester, octadecyl ester, docosyl ester, phenyl ester, 3-methylphenyl ester or 2,6-dimethylphenyl ester instead of methyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate, the reactions and treatments were conducted in the same manner as in Example 1 to give the following compounds. Tris[2-tert-butyl-4-(2-(2-ethylhexyloxycarbonyl)ethyl)phenyl]phosphite as a pale yellow oily substance Elemental Analysis C (%) H (%) P (%) Calcd. 73.36, 9.67, 3.0 Found 73.11, 9.73, 3.06 IR (cm⁻¹) ν P-O 845, 1180 ; ν C=O 1730 (Film) NMR (CDCl₃) δ 0.60 - 1.70 (m, 72H), 2.50 - 3.0 (m, 12H), 4.0 (d, 6H), 6.80 - 7.30 (m, 9H) Tris[2-tert-butyl-4-(2-(tridecyloxycarbonyl)ethyl)phenyl]phosphite as a pale yellow oily substance Elemental Analysis C (%) H (%) P (%) Calcd. 75.44, 10.46, 2.49 Found 75.57, 10.40, 2.40 IR (cm⁻¹) ν P-O 845, 1185 ; ν C=O 1730 (Film) NMR (CDCl₃) δ 0.60 - 1.70 (m, 102H), 2.40 - 3.0 (m, 12H), 4.0 (t, 6H), 6.80 - 7.30 (m, 9H) Tris[2-tert-butyl-4-(2-(octadecyloxycarbonyl)ethyl)phenyl]phosphite as white crystals, m.p. 35 - 37°C Elemental Analysis C (%) H (%) P (%) Calcd. 76.91, 11.03, 2.13 Found 77.04, 11.07, 2.19 IR (cm⁻¹) ν P-O 845, 1185 ; ν C=O 1735 (Film) NMR (CDCl₃) δ 0.60 - 1.80 (m, 132H), 2.40 - 3.0 (m, 12H), 4.02 (t, 6H), 6.80 - 7.30 (m, 9H) Tris[2-tert-butyl-4-(2-(docosyloxycarbonyl)ethyl)phenyl]phosphite as white crystals, m.p. 39 - 40°C Elemental Analysis C (%) H (%) P (%) Calcd. 77.82, 11.38, 1.91 Found 78.01, 11.30, 1.87 IR (cm⁻¹) ν P-O 845, 1185 ; ν C=O 1735 (Film) NMR (CDCl₃) δ 0.60 - 1.85 (m, 156H), 2.40 - 3.0 (m, 12H), 4.0 (t, 6H), 6.80 - 7.30 (m, 9H) Tris[2-tert-butyl-4-(2-(phenoxycarbonyl)ethyl)phenyl]phosphite as a pale yellow oily substance Elemental Analysis C (%) H (%) P (%) Calcd. 74.16, 6.87, 3.35 Found 74.45, 6.80, 3.31 IR (cm⁻¹) ν P-O 845, 1190 ; ν C=O 1755 (Film) NMR (CDCl₃) δ 1.38 (s, 27H), 2.60 - 3.10 (m, 12H), 6.80 - 7.40 (m, 24H) Tris[2-tert-butyl-4-(2-(3-methylphenoxycarbonyl)ethyl)phenyl]phosphite as a pale yellow oily substance Elemental Analysis C (%) H (%) P (%) Calcd. 74.66, 7.2, 3.2 Found 74.32, 7.31, 3.30 IR (cm⁻¹) ν P-O 850, 1190 ; ν C=O 1755 (Film) NMR (CDCl₃) δ 1.38 (s, 27H), 1.33 (s, 9H), 2.60 - 3.10 (m, 12H), 6.50 - 7.40 (m, 21H) Tris[2-tert-butyl-4-(2-(2,6-dimethylphenoxycarbonyl)ethyl)phenyl]phosphite as a pale yellow substance Elemental Analysis C (%) H (%) P (%) Calcd. 75.12, 7.5, 3.07 Found 75.39, 7.29, 2.99 IR (cm⁻¹) ν P-O 845, 1190 ; ν C=O 1750 (Film) NMR (CDCl₃) δ 1.40 (s, 27H), 2.40 (s, 18H), 2.70 - 3.15 (m, 12H), 6.70 - 7.40 (m, 18H) Example 9 A mixture of 11.7 g of dodecyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate, 3.1 g of triphenylphosphite and a slight amount of sodium hydroxide was stirred at 150 - 200°C. After the elimination of phenol, the mixture was cooled to room temperature and purified by silica gel column chromatography to give tris[2-tert-butyl-4-(2-(dodecyloxycarbonyl)ethyl)phenyl]phosphite as a pale yellow oily substance. Elemental Analysis C (%) H (%) P (%) Calcd. 75.08, 10.33, 2.58 Found 74.90, 10.21, 2.63 IR (cm⁻¹) ν P-O 845, 1185 ; ν C=O 1735 (Film) NMR (CDCl₃) δ 0.60 - 1.70 (m, 96H), 2.40 - 3.0 (m, 12H), 4.0 (t, 6H), 6.80 - 7.30 (m, 9H) Example 10 By using 4-tert-butylphenyl 3-(3-tert-butyl-4-hydroxyphenyl)propionate and tributylphosphite, the reactions and treatments were conducted in the same manner as in Example 9 to give tris[2-tert-butyl-4-(2-(4-tert-butylphenoxycarbonyl)ethyl)phenyl]phosphite. Elemental Analysis C (%) H (%) P (%) Calcd. 75.93, 8.03, 2.83 Found 76.10, 8.00, 2.98 IR (cm⁻¹) ν P-O 850, 1130 ; ν C=O 1755 (Film) NMR (CDCl₃) δ 1.31 (s, 27H), 1.38 (s, 27H), 2.60 - 3.10 (m, 12H), 6.70 - 7.40 (m, 21H).

Claims: A phosphite compound represented by the formula wherein R¹ stands for a tertiary butyl group, R² stands for a straight or branched alkyl group having 1 to 22 carbon atoms or phenyl and n stands for 2. The phosphite compound according to Claim 1 selected from the group consisting of tris[2-tert-butyl-4-(2-(methoxycarbonyl)ethyl)phenyl]phosphite, tris[2-tert-butyl-4-(2-(2-ethylhexyloxycarbonyl)ethyl)phenyl]phosphite, tris[2-tert-butyl-4-(2-(tridecyloxycarbonyl)ethyl)phenyl]phosphite, tris-[2-tert-butyl-4-(2-(octadecyloxycarbonyl)ethyl)phenyl]phosphite, tris[2-tert-butyl-4-(2-(docosyloxycarbonyl)ethyl)phenyl]phosphite, tris[2-tert-butyl-4-(2-(phenoxycarbonyl)ethyl)phenyl]phosphite and tris[2-tert-butyl-4-(2-(dodecyloxycarbonyl)ethyl)phenyl]phosphite. Use of a phosphite compound represented by the formula wherein R¹ stands for a tertiary butyl group, R² stands for a straight or branched alkyl group having 1 to 22 carbon atoms or phenyl and n stands for 2 as an antioxidant for organic materials being macromolecuar polymers, fats and oils. The use according to Claim 3 wherein the phosphite compound is used together with a hindered phenol compound. The use according to Claim 4 wherein said hindered phenol compound is selected from the group consisitng of 2,6-di-tert-butyl-4-methylphenol, 4-hydroxymethyl-2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-ethylphenol, butylhydroxyanisole, octadecyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate, distearyl (4-hydroxy-3-methyl-5-tert-butyl)benzylmalonate, propyl gallate, octyl gallate, dodecyl gallate, tocopherol, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4-methylenebis(2,6-di-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), styrene phenol, N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), 3,5-di-tert-butylhydroxybenzylphosphonic acid aminoethyl ester calcium, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane, 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-dihydroxy-3,3'-dicyclohexyl-5,5'-dimethylphenylmethane, 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6(1H,3H,5H)trione, triethyleneglycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], 2,2'-oxamide bis[ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 6-(4-hydroxy-3,5-di-tert-butylanilino)-2,4-dioctylthio-1,3,5-triazine, bis[2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl]terephthalate, 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, 3,9-bis[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane and 3,9-bis[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane acid. The use according to claim 3 wherein the phosphite compound is used together with a thioalkanoate compound selected from dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate and pentaerythritol tetrakis(β-laurylthiopropionate). The use according to claim 3 wherein the phosphite compound is used together with a light stabilizing agent. The use according to Claim 7 wherein the light stabilizing agent is selected from the group consisiting of phenyl salycylate, p-tert-butyl salycylate, p-octylphenyl salycylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxyethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-isooctyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, di-sodium 2-hydroxy-4-octadecyloxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5,5'-disulfobenzophenone, 2-hydroxy-4-(2-hydroxy-3-methacryloxy)propoxybenzophenone, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate, ethyl 2-cyano-3,5-diphenylacrylate, nickel[2,2-thiobis(4-tert-octylphenolate)]-n-butylamine, nickel bis(octylphenylsulfide), nickel bis[o-ethyl(3,5-di-tert-butyl-4-hydroxybenzyl)]phosphonate, bis(2,2,6,6-tetramethyl-4-piperidine)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, poly{[6-(1,1,3,3-tetramethyl-4-piperidyl)amino]-s-triazine-2,4-diyl}, [(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino], poly(6-morpholino-s-triazine-2,4-diyl)[(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino], 1-hydroxyethyl-2,2,6,6-tetramethyl-4-piperidinol/succinic acid condensate, cyanulic chloride/tert-octylamine/1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane condensate.

Inventors: HANAYAMA NAOKI, NAKAGAWA KAZUO, ONISHI AKIYOSHI C O PLASTICS L, HANAYAMA, NAOKI, NAKAGAWA, KAZUO, ONISHI, AKIYOSHI C/O PLASTICS LABORATORY
Applicants: MITSUBISHI PETROCHEMICAL CO, YOSHITOMI PHARMACEUTICAL, MITSUBISHI PETROCHEMICAL CO., LTD., YOSHITOMI PHARMACEUTICAL INDUSTRIES, LTD.
Application year: 1989
Main classification: C07F9
IPC codes: C07F9, C08K5, C09K15