摘要:
A process for producing dimethyl carbonate is carried out by a first step of catalytically reacting carbon monoxide with methyl nitrite to produce dimethyl carbonate; a second step of absorbing dimethyl carbonate contained in a gas fraction withdrawn from the first step by dimethyl oxalate; a third step of regenerating methyl nitrite by contacting nitrogen monoxide contained in a gas fraction withdrawn from the second step with a molecular oxygen-containing gas and methyl alcohol; a fourth step of collecting dimethyl carbonate by distilling a liquid fraction withdrawn from the second step; and a fifth step of recovering methyl nitrite from a purge gas consisting of a portion of a regenerated gas fraction withdrawn from the third step by absorbing methyl nitrite in the purge gas by methyl alcohol to provide a methyl nitrite-containing liquid fraction and a nitrogen monoxide-containing gas fraction and bringing the gas fraction into contact with a molecular oxygen and methyl alcohol, to convert nitrogen monoxide in the gas fraction to methyl nitrite and to absorb this methyl nitrite by methyl alcohol, whereby methyl nitrite and nitrogen monoxide in the purge gas is recovered and reused with a high efficiency at a high level of safety.
摘要:
An alkyl nitrite can be produced on an industrial scale with a high efficiency and with a low yield of by-products by the process wherein nitrogen oxide-containing feed gas is brought into an alkyl alcohol liquid in a distillation column reactor while circulating a liquid fraction, produced in the reactor and containing the alkyl alcohol, through a circulation path including a lower section of the reactor and a cooler to remove the reaction heat vigorously generated in the reactor, and while controlling the weight ratio of the circulating liquid fraction to the total alkyl alcohol fed into the reactor to 50:1 to 200:1, the molar ratio of the total alkyl alcohol fed to the reactor and contained in the circulating liquid fraction to nitrogen oxide in the feed gas to 20:1 to 150:1, and the content of the alkyl alcohol in the liquid fraction to 15 to 60% by weight; and the resultant gas fraction containing the target alkyl nitrite is collected from the reactor.
摘要:
Dimethyl carbonate ((CH.sub.3 O).sub.2 CO) is continuously produced by a catalytic reaction (first step) of CO with CH.sub.3 NO.sub.2, with a significantly reduced loss of CH.sub.3 ONO by the process including a second step wherein (CH.sub.3 O).sub.2 CO in a reaction product gas of the first step is absorbed by dimethyl oxalate while contacting the resultant liquid fraction with CO to recover CH.sub.3 ONO, a third step wherein CH.sub.3 ONO is regenerated from NO in the condensed gas fraction produced in the second step and molecular oxygen and CH.sub.3 OH introduced into the third step, the resultant regenerated gas fraction being recycled and reused as a feed gas for the first step, and a fourth step wherein (CH.sub.3 O).sub.2 CO contained in the liquid fraction of the second step is collected.
摘要:
A process for producing dimethyl carbonate is carried out by a first step of catalytically reacting carbon monoxide with methyl nitrite to produce dimethyl carbonate; a second step of absorbing dimethyl carbonate contained in a gas fraction withdrawn from the first step by dimethyl oxalate; a third step of regenerating methyl nitrite by contacting nitrogen monoxide contained in a gas fraction withdrawn from the second step with a molecular oxygen-containing gas and methyl alcohol; a fourth step of collecting dimethyl carbonate by distilling a liquid fraction withdrawn from the second step; and a fifth step of producing and recovering methyl nitrite from a purge gas consisting of a minor portion of a gas fraction withdrawn from one of the second step and the third step by bringing the purge gas together with an ammonia-oxidation product gas into contact with methyl alcohol in a methyl nitrite-recovering column, to thereby produce and recover methyl nitrite contained in the recovering column with a high efficiency at a high level of safety.
摘要:
Disclosed a process for purifying dimethyl carbonate which comprises distillating a mixture of dimethyl carbonate and methanol in the presence of dimethyl oxalate to separate and remove methanol.
摘要:
A process for preparing polycarbonate is composed of the steps of transesterifying a dialkyl oxalate and a phenolic compound to give a diaryl oxalate; decarbonylating the diaryl oxalate to give a diaryl carbonate; reacting the diaryl carbonate with a polyvalent hydroxyl compound in the presence of a catalyst containing an amine compound or an ammonium compound to give the polycarbonate, removing a phenolic by-product/amine by-product mixture; collecting the mixture; purifying the mixture so that the amount of the amine by-product in the mixture is reduced to give a phenolic by-product mixture not containing the amine by-product in an amount of more than 600 ppm; and, utilizing thus purified phenolic mixture as a whole or a part of the phenolic compound in the first step.
摘要:
A composition consisting essentially of a diaryl carbonate and contains a furan ring-containing compound in an amount of not more than 1 ppm is favorably employable for producing less colored polycarbonate.
摘要:
A touch panel system prevents an incorrect operation caused by an unintended contact of an object with a touch panel while suppressing a decline in sensitivity of detection of presence or absence of a touch on the touch panel. The touch panel system includes a touch invalidating section which, in a case where a specific point of a touch panel is continuously touched for a predetermined period of time, invalidates an instruction that is given, in accordance with the touch, to an electronic device including the touch panel.
摘要:
Live cells of a microorganism in a test sample are detected by the following steps: a) the step of treating the test sample with a topoisomerase poison and/or a DNA gyrase poison, b) the step of extracting DNA from the test sample, and amplifying a target region of the extracted DNA by PCR, and c) the step of analyzing an amplification product.
摘要:
The touch sensor system (1) includes: a touch panel (2) having a two-dimensional region (12) made up of a hand placing region (13) and a remainder region (14); a hand placing region processing section (3) for carrying out a process related to the hand placing region in accordance with a hand placing region touch signal corresponding to a touch to the hand placing region (13); and a plot input processing section (4) for carrying out a plot input process in accordance with a remainder region touch signal corresponding to a touch to the remainder region (14).