Abstract: A refrigerant pack is provided with a refrigerant substance containing water, a precipitating component, a non-precipitating component, and a pH indicator, and is configured such that the precipitating component precipitates when the refrigerant substance freezes and is a component not corresponding to the pH indicator, the non-precipitating component does not precipitate when the refrigerant substance freezes and is a component not corresponding to the pH indicator, a change or the presence/absence of coloring in the pH indicator is reflected before and after freezing, and the refrigerant substance changes in color.

Abstract: A refrigerant pack is provided with a refrigerant substance containing water, a precipitating component, a non-precipitating component, and a pH indicator, and is configured such that the precipitating component precipitates when the refrigerant substance freezes and is a component not corresponding to the pH indicator, the non-precipitating component does not precipitate when the refrigerant substance freezes and is a component not corresponding to the pH indicator, a change or the presence/absence of coloring in the pH indicator is reflected before and after freezing, and the refrigerant substance changes in color.

Abstract: This invention relate to a process for producing glycine by reacting glycolonitrile, carbon dioxide and ammonia in the presence of water, comprising subjecting first water, glycolonitrile, carbon dioxide and ammonia to a pre-reaction at 80.degree.-120.degree. C. for 0.5-1 hour and then to the main reaction at 150.degree.-200.degree. C. and a process further comprising recycling the remaining mother liquor having separated the glycine from the reaction solution obtained by the above process to the system comprising water, glycolonitrile, carbon dioxide and ammonia to carry out the aforesaid pre-reaction and/or main reaction.

Abstract: A process for preparing glycine which comprises the steps of reacting glycolonitrile, carbon dioxide gas, ammonia and water to obtain a reaction solution containing glycine, concentrating this reaction solution in two steps, recycling a gaseous phase portion formed in a primary concentration step to a reaction zone, and recycling to the reaction zone, a mother liquor left after glycine crystals have been separated from a concentrate obtained in a secondary concentration step.

Abstract: A process is provided for the purification of methacrylic acid. The process can easily remove dibasic acids and aldehydes containing in trace amounts as impurities. According to the process, crude methacrylic acid obtained as an aqueous solution by vapor-phase catalytic oxidation of isobutylene, tertiary butanol, methacrolein or isobutyl aldehyde is treated with at least one compound selected from the group consisting of m-aminophenol, m-phenylenediamine, 2,4-diaminotoluene and 2,4-diamino-diphenylamine, followed by distillation, optionally, in the presence of a p-phenylene diamine.