- Carbamoyloxa-bridged cyclophanes: Macrocyclization by double transesterification of dimethyl m-xylylenedicarbamate with α,ω-dihydroxy compounds
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A series of macro-sized (16-24-membered) carbamoyloxa-bridged cyclophanes 3a-k was prepared by sequential inter- and intramolecular transesterifications of dimethyl m-xylylenedicarbamate with α,ω-dihydroxy compounds 2a-k in good yields (15-74%) without th
- Irie,Yamamoto,Kishikawa,Kohmoto,Yamada
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- Method for preparing high-purity m-xylylene diisocyanate from non-phosgene
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The invention relates to the technical field of isocyanate preparation, in particular to a method for preparing high-purity m-xylylene diisocyanate from non-phosgene. The method for preparing the high-purity m-xylylene diisocyanate from the non-phosgene comprises the following steps: subjecting m-xylylenediamine and dimethyl carbonate to reacting under the action of a catalyst A to obtain methyl m-xylylene dicarbamate; and carrying out a decomposition reaction on methyl m-xylylene dicarbamate under the action of a catalyst B, emptying methanol through nitrogen replacement in the reaction process, and carrying out reduced-pressure distillation after the reaction is finished so as to obtain m-xylylene diisocyanate, wherein the catalyst A is a supported catalyst taking Lewis acid as an activecomponent and nano-SiO2 or nano-TiO2 as a carrier, and the catalyst B is an ultrafine composite oxide. The preparation method of the invention is good in product selectivity, high in yield, high in purity and free of catalyst residues, product quality is improved, and the requirements of high-end fields are met.
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Paragraph 0036-0061; 0076-0079
(2021/03/31)
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- The manufacturing method of the carbamate compounds
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The present invention addresses the problem of providing a method for producing an industrially-suitable carbamate compound without requiring a complicated operation, wherein a carbamate compound of a quality suitable for producing an isocyanate compound is produced by reacting a carbonate compound and an amine compound. Said problem is solved by a method for producing a carbamate compound characterized by reacting an amine compound and a carbonate compound under the presence of at least one base selected from a group comprising alkali metal alkoxides and alkaline earth metal alkoxides, and then adding 0.01 to 0.5 moles of water to 1 mole of an amino group of the amine compound, and further reacting the amine compound and carbonate compound.
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Paragraph 0117-0120
(2017/10/07)
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- PROCESS FOR PREPARING A CARBAMATE COMPOUND
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There is provided a process for preparing a carbamate compound, which is easy and commercially advantageous in that a carbamate compound can be produced with high yield from an amine compound and a carbonate compound. A process for preparing a carbamate compound which comprises the step of reacting an amine compound which has at least one amino group per molecule wherein the amine compound is selected from the group consisting of an aliphatic amine which may be substituted by an alicyclic group or an aromatic group or which may be interrupted by an alicyclic group or an aromatic group, and an alicyclic amine which may be substituted by an aliphatic group, with a carbonate compound in the presence of at least one organic solvent selected from the group consisting of a saturated cyclic hydrocarbon, an unsaturated cyclic hydrocarbon, and a non-cyclic ether by using a hydrolase.
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Page/Page column 10
(2012/12/13)
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- Method for producing carbamates and method for producing isocyanates
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A method for producing carbamates that enables carbamates to be produced at low costs, with high selectivity and high yield, and in a simple manner, and a method for producing isocyanates that enables isocyanates industrially used to be produced by using the carbamates obtained by the carbamates producing method. Nonaromatic amine selected from the group consisting of aliphatic amine, alicyclic amine, and aralkyl amine is allowed to react with alkylaryl carbonate to thereby produce carbamates. Also, the carbamates thus obtained are thermally decomposed to thereby produce isocyanates. When carbamates are produced in this method, alkyl carbamates can be obtained with high selectivity and at high yield by using simple equipment. Also, when isocyanates are produced in this method, polyisocyanates used industrially as the raw material of polyurethane can be produced in a simple manner and with efficiency.
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- Process for producing isocyanate compound
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There is disclosed a process for producing an isocyanate compound from a formamide compound or an amine compound which comprises (a) the first reaction step of reacting a formamide compound with dimethyl carbonate in the presence of an alkali catalyst, or
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