Purifying technical grade camphor prodn. - by melt crystallisation with at least one reheating step once initial crystallisation has ceased

摘要

Impurities are sepd. from technical grade (at least 50%) camphor (I) by melting the (I), and then cooling to allow pure (I) to crystallise out. The crystallisation process which initially sets in and continues practically to a standstill, is set in motion against at least once by a heating step. Pref., 1-4 heating steps are employed. USE/ADVANTAGE - This method gives pure (I) without the need for solvent recrystallisation (and consequently drying), so avoids loss of both product and solvent. Pure (I) is used as a plasticiser for cellulose nitrate (in prepn. of celluloid and nitrocellulose lacquer) or cellulose propionate. It is also useful as a pharmaceutical (antiseptic or cardiac stimulant);perfume component; clothes moth repellent; in smokeless gunpowder or primers, and as fumigant. (4pp Dwg.No.0/0)