n-Hexane, Benzene and Other Aromatic Components in Petroleum Distillate Solvents in Japan

Among the 7 types of natural solvent mixtures listed as third class solvents in the Ordinance on Prevention of Organic Solvent Poisoning, 5 types (134 samples) of petroleum distillate solvents (PDS) were collected from various parts of Japan in 1986 and 1987, and analyzed for n-hexane, benzene and 4 other aromatics by capillary gaschromatography. In addition, 3 samples of turpentine oil, 1 sample of reagent grade coal tar naphtha, 14 samples of JIS solvent gasoline of various sorts and 4 samples of drug store-bought spot remover were analyzed for reference. The mean concentrations of n-hexane and benzene in total PDS samples were 2.57% and 0.41%, respectively, but the concentrations of the 7 chemi-cals studied dispersed over very wide ranges and it was not possible to identify typical compositions even after the results were grouped according to use patterns. From chromatograms, it was possible to classify the PDS into two groups of "low" and "high" boiling point PDS, with higher risk for the former to contain n-hexane and benzene. All rubber surface softener samples examined belonged to the former, whereas all dry-cleaning solvents to the latter. Thinner-cleaner samples for print-ing and painting distributed in two groups evenly. Turpentine oil and coal tar naphtha samples analyzed contained no n-hexane nor benbene at all. Both n-hexane and benzene (up to 13.7 and 4.2%, respectively) were detected in spot re-movers.