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    • 7. 发明专利
    • DE1518017C3
    • 1975-03-13
    • DE1518017
    • 1965-05-03
    • MONSANTO CHEMICALS LTD., LONDON
    • BROWN, JOSEPH PATRICK, LLANGOLLEN, DENBIGSHIRE (GROSSBRITANNIEN)
    • C07D339/04C08K5/45
    • Compounds having the formula where (a) n has the value 1, and X represents hydrogen or a radical having the formula or (b) X represents a salt-forming atom or group and n is an integer determined by the valency of X; and where in each instance R represents an aromatic or aliphatic group are prepared (a) by reacting sulphur with an olefin having the formula R(CH3)C=CH2, or with a precursor capable of giving rise to such an olefinic compound under the reaction conditions, in the presence of an N-alkylated carboxylic amide, e.g. dimethylformamide, or in the presence of an amine and a polar organic solvent, e.g. tetrahydrothiophen dioxide, or (b) by the reaction of a 1-2 dithiole 3-thione derivative with sulphur and/or hydrogen sulphide in the presence of an N-alkylated carboxylic amide or an amine and a polar organic solvent. In each case the primary product is an amine salt of the 5-mercapto 1,2-dithiole 3-thione, from which the free 5-mercapto 1,2-dithiole 3-thione can be liberated by acidification. The 5,51 - bis - (3 - thione 1,2 - dithiolyl) disulphide may be formed as a by-product of the acidification, but is preferably produced by the oxidation of the corresponding mercapto compound, e.g. by persulphate, hypochlorite, hydrogen peroxide, or oxygen. Specified olefinic starting material are a -methyl styrene, 4 - chloro - a - methyl styrene, 3 - methyla - methyl styrene, isobutylene, 2,3 - dimethyl butene - 1, diisobutylene, 2,4,4,6,6- pentamethyl heptene-1,2-cyclohexyl propene-1, 2-benzylpropene-1, and precursors which may dehydrate or dehydrohalogenate in the required manner are t-butanol, and 2-phenyl-propan-2-ol. The compounds may be acidified to form the free mercaptans, or the sodium, copper, zinc, nickel, lead, dimethylamine, cyclohexylamine or morpholine salts may be formed. The group R in the 5,51-bis-(3-thione, 1,2-dithiolyl) disulphides may be phenyl, neopentyl or cyclohexyl. From 3 to 7 mole of sulphur are preferably used per mole of olefinic compound, and the reaction is generally effected at a temperature of 100 DEG to 250 DEG C. for from 6 to 96 hours. The compounds are useful as accelerators in the vulcanization of natural and synthetic rubbers (see Division C3) and the invention includes the compounds per se except that in which R is phenyl and X is hydrogen.ALSO:A vulcanization accelerator for natural or synthetic rubber comprises a compound having the formula (see Division C2) where (a) n has the value 1 and X represents hydrogen or a radical having the formula or (b) X represents a salt-forming atom or group and n is an integer determined by the valency of X; and where in each case R is an aromatic or aliphatic group.
    • 10. 发明专利
    • FR2210624A1
    • 1974-07-12
    • FR7342531
    • 1973-11-29
    • MONSANTO CHEMICALS
    • C08F2/20C08F1/11C08F33/08C08F45/22
    • 1411444 Vinyl aromatic polymers and foamable beads thereof MONSANTO Ltd 19 Nov 1973 [14 Dec 1972] 57661/72 Headings C3C and C3P Beads of vinylaromatic homo- or copolymer are prepared by polymerizing a vinyl aromatic monomer in an aqueous suspension system in the presence of a dissolved suspending agent, a polymerization catalyst and from 0.0001 to 0.008% of the total monomer weight of an alkyl hydrogen polysiloxane comprising the repeating unit -Si(HR)-O- where R is a C 1 -C 4 alkyl group. A volatile blowing agent, e.g. pentane, may also be present during polymerization. The monomer may be styrene, α methyl styrene, vinyl toluene or chlorostyrene. The suspending agent may be an inorganic water soluble salt or a water soluble organic polymer, e.g. polyvinyl alcohol or a copolymer of vinyl alcohol and a vinyl ester or a mixture of different polyvinyl alcohols. In the example styrene is polymerized in the presence of water, hydrolysed polyvinylacetate, benzoyl peroxide, pentane and methyl hydrogen polysiloxane to form polymer beads which are washed and contain 0.3% occuled water: The foamable beads are prefoamed, aged and moulded into blocks.