Kuraray Co., Ltd.

Hidetsugu Tanaka

Sunao Kyo

Katsuhiko Hayashi

Hideaki Oka

Tsumoru Renge

Haruo Tsuchiya

Disclosed are improved procedures for preparing pinacolone from compounds of general formula (I) ##STR1## wherein, either adjacent two of A, B, C and D form a single bond between them and the remaining two are hydrogen atoms, or both A and D are hydrogen atoms and one of B and C is a hydrogen atom and the other represents OH, Cl, Br, HSO.sub.4, H.sub.2 PO.sub.4 or ClO.sub.4, and a new procedure which enables preparing pinacolone from a compound of general formula (II) ##STR2## wherein, both W and Y are each hydrogen atoms and X and Z are the same or different and each represents OH, Cl, Br, HSO.sub.4, H.sub.2 PO.sub.4, ClO.sub.4 or RCOO wherein R is a hydrogen atom or an alkyl group of 1 to 3 carbon atoms, or one of W and Y is a hydrogen atom and the other forms a single bond together with X, and Z represents OH, Cl, Br, HSO.sub.4 H.sub.2 PO.sub.4, ClO.sub.4 or RCOO where R is defined as above. In the process of preparing pinacolone from compounds of formula (I) by reacting them with formaldehyde in the presence of a strong inorganic acid, the process can be improved by adding a salt of a strong inorganic acid, or a compound of formula (II). Pinacolone can also be produced by heating a compound of general formula (II) in the presence of a strong inorganic acid and this reaction, too, can be improved by the addition of a salt of a strong inorganic acid. The use of a salt of a strong inorganic acid according to the invention makes it possible to reduce the concentration and the amount of strong acid normally required, and to improve the yield of pinacolone.

Production of pinacolone

Production of an alken-2-ol-1, or of an alken-2-ol-1 and an alkanol-1 from the corresponding alken-3-ol-1 is described. The above compound or compounds can be produced with good selectivity by converting an alken-3-ol-1 to the boric acid ester, and, then, contacting the ester with a palladium catalyst in the presence of hydrogen or, alternatively, by carrying out the latter-mentioned step under conditions favorable to the formation of said boric acid ester and, thereafter, subjecting the reaction product to solvolysis.

Method for the production of alken-2-ol-1 or of alken-2-ol-1 and

Polyhydric alcohols can be produced in high selectivity from substituted 1,3-dioxanes containing at least one hydroxyalkyl group by heating, in the presence of water, said 1,3-dioxane or mixtures thereof in contact with boric acid, boric acid anhydride or a boron-containing compound capable of forming boric acid under the reaction conditions and recovering the polyhydric alcohols corresponding to said 1,3-dioxanes.

Process for the production of polyhydric alcohols

The 3-methyl-3-butene-1-ol contained in the oily mixture obtained in the production of isoprene by the reaction of isobutene and formaldehyde through the intermediate 4,4-dimethyl-1,3-dioxane can be isolated by adding boric acid to said mixture to form the boric acid ester of 3-methyl-3-butene-1-ol and recovering the higher boiling fraction having a boiling point of above 160.degree.C.

Growing community of inventors

Ibaragi, Japan

Hidetsugu Tanaka