摘要:
There is disclosed a process for efficiently producing hydrogen cyanide at a reaction temperature of preferably 250.degree. to 550.degree. C. by a catalytic dehydrative reaction of formamide which comprises employing as a catalyst, a manganese oxide (MnO) and/or a magnesium oxide (MgO) each modified with an alkali metal (Na, K, Rb, Cs, etc. ). The above process is capable of producing hydrogen cyanide at an enhanced conversion efficiency of formamide and at a high selectivity while minimizing the by-production of ammonia. The use of the catalyst comprising as a principal component, MnO modified with an alkali metal is particularly effective in prolonging its service life and enables a long-term stable operation.
摘要:
A process for preparing a silica-titania catalyst by adding an acidic solution containing a silicon compound such as sodium silicate and a titanium compound such as titanium sulfate dissolved therein to a solution of a compound such as ammonium bicarbonate to bring about co-precipitation, in which the acidic solution is a highly concentrated nitric acid-acidic or sulfuric acid-acidic solution, and a ratio of the dissolved titanium compound in the acidic solution is regulated in a certain range.According to this process, a catalyst capable of exerting a high performance in an esterification reaction and the like can be efficiently obtained.
摘要:
A process for preparing a carboxylic acid ester which includes subjecting a carboxylic acid and an alcohol or a phenol to an esterification reaction in the presence of a silica-titania catalyst. The silica-titania catalyst is prepared by adding an acidic solution containing a silicon compound and a titanium compound dissolved therein to a solution of a basic compound to bring about co-precipitation, in which the acidic solution is a nitric acid-acidic solution or a sulfuric acid-acidic solution, a ratio of the amount (gram equivalent) of nitric acid or sulfuric acid to the amount (mol) of the silicon compound in the acidic solution is 0.5 to 50 and the amount of the titanium compound in the acidic solution is such that a ratio of titania (TiO.sub.2) in the silica-titania catalyst is 1 to 50% by weight.
摘要:
A process for preparing an amide by hydrating a cyanohydrin with a denatured manganese dioxide catalyst. The catalyst is prepared by reacting an aqueous permanganate solution and an aqueous manganese (II) compound solution in an acidic aqueous solution at a temperature of 70.degree. C. to 150.degree. C.
摘要:
Disclosed is a process for producing methyl methacrylate which comprises:(I) a step of reacting prussic acid and acetone to form acetonecyanhydrin;(II) a step of hydrating the acetonecyanhydrin obtained in the step (I) to form .alpha.-hydroxyisobutyric acid amide;(III) a step of dehydrating the .alpha.-hydroxyisobutyric acid amide obtained in the step (II) to form methacrylic acid amide;(IV) a step of reacting the methacrylic acid amide obtained in the step (III) and methyl formate to form methyl methacrylate and formamide; and(V) a step of dehydrating formamide separated from the product obtained in the step (IV) to form prussic acid and recycling said prussic acid as a starting material in the step (I).The process produces methyl methacrylate with high selectivity without undesirable by-product such as ammonium sulfate.
摘要:
Carboxylic acid esters and formamide are efficiently obtained for reacting carboxylic acid amides and formic acid esters, or carboxylic acid amides, alcohols and carbon monoxide in the presence of an alkaline earth metal oxide catalyst.
摘要:
Disclosed is a process for producing .alpha.-hydroxy-carboxylic acid amide represented by the formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are as defined in the specification, by a catalytic hydration reaction of cyanohydrin represented by the formula (II): ##STR2## which comprises using a modified manganese dioxide containing one or more of an alkali metal element and an alkaline earth element in an amount of 0.05 to 0.5 based on the manganese element in terms of atomic ratio.
摘要:
A process for producing .alpha.-hydroisobutyric acid amide by a hydration reaction of acetonecyanohydrin in the presence of a catalyst containing manganese dioxide as a main component, and also in the presence of an oxidizing agent. In accordance with the process, the service life of the catalyst is increased, and the .alpha.-hydroxyisobutyric acid amide is produced in a high yield.
摘要:
A process for producing a denatured manganese dioxide for the hydration reaction of cyanohydrins comprising reacting an aqueous permanganate salt solution and an aqueous manganese (II) compound in an acidic aqueous solution at a temperature of 70.degree. C. to 130.degree. C. is disclosed. The manganese dioxide catalyst obtained by the process exhibits a high activity over a long period in the preparation of an amide by the hydration of the corresponding cyanohydrin.
摘要:
A process for production of 2,6-dimethylnaphthalene is disclosed; comprising the steps: (1) an acylation step where 2,4-dimethylisobutyrophenone is produced from m-xylene, propylene and carbon monoxide: (2) a hydrogenation step where the carbonyl group of the above 2,4-dimethylisobutyrophenone is hydrogenated: and (3) a dehydrogenation and cyclization step where the above hydrogenated product is subjected to dehydrogenation and cyclization to produce the desired 2,6-dimethylnaphthalene. The process enables efficiently producing high quality or high purity 2,6-dimethylnaphthalene.