Abstract: A process for producing coumarin or a derivative thereof, which process comprises dehydrogenation of 3,4-dihydrocoumarin or a derivative thereof in the presence of a palladium catalyst by heating under reduced pressure.

Abstract: A process for producing coumarin and a derivative thereof represented by formula (2): ##STR1## wherein R.sub.1 to R.sub.4 each represents a hydrogen atom, a methyl group, or an ethyl group, provided that at least two of R.sub.1 to R.sub.4 each represents a hydrogen atom,the process comprising the step of heating a 3-(2-cyclohexanoyl)propionic acid ester represented by formula (1): ##STR2## wherein R.sub.1 to R.sub.4 are as defined above and R.sub.5 represents an alkyl group having from 1 to 4 carbon atoms,in the presence of a palladium catalyst, thereby to allow the ester of formula (1) to undergo cyclization and dehydrogenation reactions, the latter stage of the reactions, in which the conversion of the 3-(2-cyclohexanoyl) propionic acid ester used as a starting material has reached about 80% or more, being conducted at a higher temperature than that for the former stage of the reactions.

Abstract: A process for producing a 3,4-dihydrocoumarin compound represented by formula (II): ##STR1## wherein R.sub.1 to R.sub.4 are as defined in the specification, comprising the steps of:(1) heating a 3-(2-cyclohexanoyl)propionic acid ester compound represented by formula (I): ##STR2## wherein R.sub.1 R.sub.5 are as defined in the specification, in the presence of at least one solid metal catalyst, thereby to allow said compound of formula (I) to undergo ring formation and dehydrogenation to yield said 3,4-dihydrocoumarin compound of formula (II) and, as a by-product, a coumarin compound represented by formula (III): ##STR3## wherein R.sub.1 to R.sub.

Abstract: A process for producing a coumarin derivative represented by formula (II): ##STR1## wherein R.sub.1 to R.sub.4 are as defined in the specification, comprising the step of: subjecting to a ring formation and dehydrogenation reaction a 3-(2-cyclohexanoyl)-propionic acid ester derivative represented by formula (I): ##STR2## wherein R.sub.1 to R.sub.4 are as defined in the specification, the ring formation and dehydrogenation reaction being (1) conducted by use of a catalyst comprising a carrier having supported thereon palladium and either of chromium oxide and chromium hydroxide, or (2) conducted by use of a catalyst comprising a carrier having supported thereon palladium or a catalyst comprising a carrier having supported thereon palladium and either of chromium oxide and chromium hydroxide, in the presence of a promoter which is at least one member selected from the group consisting of magnesium trisilicate, zirconia, metallic chromium, and metallic tungsten.

Abstract: A process for producing 3,4-dihydrocoumarin comprising cyclization and dehydrogenation of a 3-(2-cyclohexanoyl)propionic acid ester, in which a reaction mixture obtained by the cyclization and dehydrogenation is washed with an alkali to reduce the dihydrocinnamic acid content of the reaction mixture to 1% by weight or less and/or previously distilling the reaction mixture to remove high-boiling substances, and then subjected to rectification to recover 3,4-dihydrocoumarin. The thus obtained 3,4-dihydrocoumarin has high purity and high quality sufficient for use as a perfume as it is.

Abstract: A method for producing a cycloalkanol in high yield by hydrating cycloalkene with a specific catalyst is disclosed. The catalyst is obtainable by ion-exchanging all or a part of the cations of a crystalline gallium silicate with hydrogen ions. It has a specific composition defined by the general formula and is characterized by the X-ray diffraction pattern.

Abstract: A industrially excellent method for producing a cycloalkanol by the hydration of a cycloalkene having from 4 to 8 carbon atoms with an aromatic sulfonic acid as a catalyst which comprises carrying out said hydration in the presence of a phenol.

Abstract: An industrially excellent method for separating cyclohexanol which comprises carrying out the hydration of cyclohexane in the presence of an acid, and bringing the reaction solution into contact with a mixed solution of a hydrocarbon and phenol to extraction-separate cyclohexanol from the reaction solution.

Abstract: A method for producing a cycloalkanol important as a material for caprolactam, adipic acid and the like by the hydration of a cycloalkene with a solid acid as a catalyst, which comprises carrying out said hydration in the presence of a phenol.

Abstract: A method for producing cycloalkanols important as a material for caprolactam, adipic acid and the like, which comprises carrying out the catalytic hydration of a cycloalkene using as a catalyst an aromatic sulfonic acid having at least one hydroxyl or ether group and separating the resulting cycloalkanol from the reaction solution by extraction.

Abstract: A method for producing alicyclic alcohols by the hydration of olefins in the presence of an aromatic sulfonic acid, which comprises incorporating molybdic acid or its salt and/or vanadium oxide, vanadic acid or its salt in the reaction system. The alicyclic alcohols are useful as intermediates for caprolactam, adipic acid, insecticides, etc.