Kuraray Co., Ltd.

Sunao Kyo

Hidetsugu Tanaka

Katsumi Omura

Tsumoru Renge

Osamu Yamada

Yoichi Ninagawa

Katsuhiko Hayashi

Hideaki Oka

Takayoshi Osaki

Koichi Kushida

Akira Mochizuki

Haruo Tsuchiya

Ken-ichi Hino

Tumoru Renge

Novel alternate copolymers consisting of isopentenyl compounds having a specific structure and certain types of unsaturated compounds are provided.

Novel alternate copolymers

A process for producing isoprene in good yield is provided. The process is characterized in that an alkyl tertiary butyl ether and a formaldehyde source are fed, together with water, into a acidic aqueous solution continuously or intermittently while maintaining the reaction pressure in an adequate range and at the same time distilling off the product isoprene, unreacted starting materials, isobutene and tertiary butanol, together with water, from the reaction zone.

Process for producing isoprene

A process for producing isoprene in good yield is provided. The process is characterized in that isobutene and/or tertiary butanol and a formaldehyde source are fed, together with water, into an acidic aqueous solution continuously or intermittently while maintaining the reaction pressure in an adequate range and at the same time distilling off the product isoprene and unreacted starting materials, together with water, from the reaction zone.

A process for producing isoprene, which comprises decomposing a mixture of at least two compounds represented by the general formula ##STR1## wherein (i) W and Y each represent a hydrogen atom, and X and Z are identical or different and each represent the group OR, (ii) W and X together form a single bond, Y represents a hydrogen atom and Z represents the group OR, (iii) W represents a hydrogen atom, X and Y together form a single bond, and Z represents the group OR, or (iv) W represents a hydrogen atom, X represents the group OR, and Y and Z together form a single bond, in which R represents a hydrogen atom, a methyl group, a methoxymethyl group, a methylbutenyl group, a methylbutenyloxymethyl group, a 1,1-dimethyl-3-hydroxypropyl group, a 1,1-dimethyl-3-hydroxypropyloxymethyl group, a 3-methyl-3-hydroxybutyl group, a 3-methyl-3-hydroxybutyloxymethyl group, a 1,1-dimethyl-3-methoxypropyl group, a 1,1-dimethyl-3-methoxypropyloxymethyl group, a 3-methyl-3-methoxybutyl group or a 3-methyl-3-methoxybutyloxymethyl group, at least one compound of the mixture being a compound of general formula (I) in which R is a methoxymethyl group, a methylbutenyloxymethyl group, a 1,1-dimethyl-3-hydroxypropyloxymethyl group, a 3-methyl-3-hydroxybutyloxymethyl group, a 1,1-dimethyl-3-methoxypropyloxymethyl group or a 3-methyl-3-methoxybutyloxymethyl group, in the presence of water and an oxygen-containing boron compound selected from the group consisting of boron-oxyacids and boron compounds capable of generating the boron-oxyacids in situ under the reaction conditions, in the liquid phase at a temperature of at least 150.degree. C. while adjusting the ratio of the oxygen-containing boron compound to the entire water present in the reaction system such that the weight ratio of ortho-boric acid to water, calculated on the assumption that all the oxygen-containing boron compound changes in aqueous solution to orthoboric acid, is at least maintained at 15:85.

A process for producing a conjugated diene represented by the general formula ##STR1## wherein R.sub.3, R.sub.4 and R.sub.5 each represent a hydrogen atom, or any one of them represents a methyl group and the other two each represent a hydrogen atom, which comprises heating an alkane-1,3-diol represented by the general formula ##STR2## wherein R.sub.1 and R.sub.2 each represent a hydrogen atom, or one of them represents a hydrogen atom and the other represents a methyl group, to a temperature of at least 130.degree. C. in the liquid phase in the presence of water and a boron-oxyacid or an oxygen-containing boron compound capable of forming a boron-oxyacid it under the reaction conditions.

Process for producing conjugated dienes

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.

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Abiko, Japan

Sunao Kyo