Abstract: A urethane resin composition for an optoelectric conversion element sealer according to the present invention is a urethane resin composition for an optoelectric conversion element sealer comprising a component (A) containing a compound having isocyanate groups and a component (B) containing a compound having hydroxyl groups, wherein the compound having isocyanate groups is at least one compound selected from the group consisting of an aromatic isocyanate having a structure in which the isocyanate groups are not directly bonded to a benzene ring, an aliphatic isocyanate, an alicyclic isocyanate, and derivatives of these isocyanates.

Abstract: A process for the preparation of 5,6,7,8-tetrahydrofolic acid which comprises dissolving and/or suspending folic acid or dihydrofolic acid in an aqueous solution containing an inorganic base, and bringing the resulting solution or suspension into contact with hydrogen in the presence of a noble metal catalyst while maintaining its pH at 5-9, thereby catalytically hydrogenating the folic acid of dihydrofolic acid into 4,5,6,7-tetrahydrofolic acid.

Abstract: Disclosed is a process for the preparation of an aminoaryl thiophosphate or phosphate which comprises hydrolyzing an N-acetylaminoaryl thiophosphate or phosphate by heating it in an aqueous solution of a mineral acid. The N-acetylaminoaryl thiophosphate or phosphate can be obtained by condensing an anhydrous alkali metal salt of an N-acetylaminophenol with phosphorus thiochloride or phosphorus oxychloride at a high temperature in the presence of an inert organic solvent or by condensing an N-acetylaminophenol with phosphorus thiochloride or phosphorus oxychloride in the presence of an alkali metal hydroxide or carbonate, water, and an organic solvent.

Abstract: Disclosed is a process for the preparation of an ester compound selected from phosphoric esters and thiophosphoric esters which comprises reacting a hydroxyl-containing organic compound with phosphorus oxychloride or phosphorus thiochloride in the presence of the hydroxide or carbonate of an alkali metal, water, and an organic solvent.

Abstract: 2-Phenyl-1.2.3-triazole-4-carboxaldehydes having the formula: ##STR1## are obtained by oxidizing a 2-phenylglycosotriazole having the formula: ##STR2## wherein R is hydrogen, halogen, methyl, carboxyl, a sulfonic acid group or the alkali metal salt thereof, n is 2 or 3, R' is hydroxymethyl when n is 2 and is hydroxymethyl or methyl when n is 3, with an oxide of manganese such as manganese dioxide or manganese oxide in dilute sulfuric acid of 20 to 80 wt. % concentration at a temperature of 0.degree. to 80.degree. C. The oxidation reaction is carried out in a dispersed state for from 2 to 100 hours and the resultant aldehyde is separated from the reaction mixture by extraction with an organic solvent. The purity of the aldehyde thus obtained is higher than 85 wt. % and the yield is 40% to quantitative on the basis of 2-phenylglycosotriazole. The aldehyde can be further purified by convenient means.