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

Abstract: 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.

Abstract: 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.

Abstract: 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-methoxybutyloxymethy

Abstract: 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.

Abstract: 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, anda 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.