Evaluation of the replacement of benzene by cyclohexan as a residual solvent in the obtainment of absolute ethyl alcohol

Abstract

Introduction: Absolute ethyl alcohol, also known as pure alcohol or anhydrous alcohol, is obtained by dehydrating the hydrated alcohol with the aid of benzene or replacing it with cyclohexane. Simple or fractional distillation of ethanol does not result in an alcoholic concentration greater than 95%. Alcohol or absolute ethanol has a minimum concentration of 99.6%. It belongs to the class of the alcohols, being from the sugar cane or the corn the two most common forms of being produced. In its composition, depending on the route of synthesis, it may contain aromatic hydrocarbons such as benzene, a highly toxic and carcinogenic chemical compound. This compound is one of the substances which arouses great interest as it is a solvent present in the formulation of various products of free access to the population. Absolute alcohol is widely used as a raw material for various products such as detergents, gasoline, aeromodelling, fuel preparation, household cleaning products, hand hygiene, and mainly in pharmaceutical and cosmetic formulas. Objective: To evaluate the detection and quantification of benzene and its substitution by cyclohexane as a possible residue of the absolute alcohol synthesis route commercialized in drugstores in the central-western region of Minas Gerais during the period of September and October 2017. Method: The method used for analysis was that of residual solvents recommended by the United States Pharmacopeial Convention, USP 40 NF 35, page 2616, by the gas chromatography technique. Conclusion: All the samples tested presented gas chromatographic test content in accordance with the parameters required by ANVISA. The samples of the manufacturers were safe for human use in relation to the benzene concentration and the use of cyclohexane in the alcohol dehydration process was proven.