Abstract: This invention aims to develop a chitin oligomer composition and/or a chitosan oligomer composition wherein the content of an oligomer from a trimer to a decamer is 60% or more, and to develop a process for preparing the above-mentioned oligomer composition. The object of the invention can be achieved by mixing hydrofluoric acid or hydrohalogenated acid other than hydrofluoric acid and hydrofluoric acid with a chitin-based material and/or a chitosan-based material.

Abstract: In order to subject a cellulosic material such as insulating paper onto and into which transformer high-voltage insulating oil containing PCB has adhered and permeated to washing that removes the PCB etc. to an undetectable value, the cellulosic material to which PCB etc. has adhered is placed in DMI, sulfolane or other aprotic solvent containing an alkali such as caustic soda and stirred.

Abstract: The invention discloses a bait for fishes and shellfishes characterized in that the bait comprises a matrix material containing a microorganically fermented product of a plant residue obtained by separating from a plant at least one liquid selected from the group consisting of vegetable juice, fruit juice, plant essential oil, juice extracted from a processed plant product, plant milk and mixtures thereof, or disintegrated product of said microorganically fermented product, wherein the matrix material has incorporated therein (A) an amino acid having 2 or 3 carbon atoms, and (B) amino acid having at least 4 carbon atoms in an (A)/(B) molar ratio of 1:1 to 40:1.

Abstract: A safe and reliable method of decomposing halogenated aromatic compounds, wherein a heat-resistant alkaline polar solvent containing halogenated aromatic compounds is contacted with a alkali at a temperature ranging from about 100.degree. C. to 300.degree. C. in order to decompose the halogenated aromatic compounds. The used solvent is removed of solid contents of salts, alkalis and the like, whereby it can be recycled.

Abstract: A safe and reliable method of removing halogenated aromatic compounds present in small amounts in hydrocarbon oil constituted mainly by non-aromatic hydrocarbon oil. The hydrocarbon oil is contacted with a heat-resistant alkaline polar solvent in the presence of an alkaline at a temperature ranging from about 100.degree. C. to 300.degree. C., and the non-aromatic hydrocarbon oil and heat-resistant alkaline polar solvent are then separated, thereby removing the halogenated aromatic compounds from the hydrocarbon oil.

Abstract: A process for preparing a polyarylene thioether, comprising oxidation coupling polymerizing with oxygen and a catalyst in the presence of an acid, at least one compound selected from the group consisting of thiophenols of the formula (II): ##STR1## wherein R.sup.9 to R.sup.12 are identical or different and each is hydrogen, alkyl having 1 to 10 carbon atoms, halogen or alkoxyl having 1 to 10 carbon atoms. Reaction conditions of the process are very mild, and the process is relatively simple and easy. In addition, the process is commercially advantageous in that very inexpensive reactants and catalysts can be used.

Abstract: A process for preparing a polyarylene thioether, comprising oxidation polymerizing at least one compound selected from the group consisting of diaryl disulfides represented by the formula (I): ##STR1## wherein, S is a sulfur atom, R.sup.1 to R.sup.8 are identical or different and each is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a halogen atom or an alkoxyl group having 1 to 10 carbon atoms, with at least one catalyst selected from the group consisting of vanadyl acetylacetonato, vanadyltetraphenyl porphyrin, vanadium acetylacetonato, vanadyl porphyrin, vanadium porphyrin, oxymolybdenum acetylacetonato and oxytungsten acetylacetonato, in the presence of an acid. Reaction conditions of the process are very mild, and the process is relatively simple and easy. In addition, the process is commercially advantageous in that very inexpensive reactants and catalysts can be used.