Abstract

This study was carried out to develop a green, simple and cost-effective route for synthesis of sodium cyanidevia aquohydrolysis of linamarin a cyanogenic glucoside found in cassava (Manihot esculenta Crantz). Two procedures were employed and compared, the acid hydrolysis method and direct (aquo) hydrolysis. The CN– ion released was reacted with Na+ via ion exchange to replace the hydroxyl ion (OH–) and yielded NaCN. The NaCN was crystallized via evaporation in an air ventilated oven by maintaining the temperature of the reaction solution at 100oC. The crystalized salt was quantified using the modified Vogel’s Argentometric method of cyanide quantification. The concentrations were found to be 10.56 mg/g for whole tuber, 13.92 mg/g for tuber tissue and 4.5 mg/g for cassava peels. Analyte grade sodium cyanide purchased off shelf was used as a reference. The crystals were characterized using, X-ray diffraction analysis; the X-ray diffractogram confirmed the products from acid hydrolysis was a cyanogen (CN2CN2) while the product from direct hydrolysis was sodium cyanide. The X-ray diffraction peaks of the NaCN from the direct hydrolysis was compared with the X-ray diffractogram of the reference analyte grade NaCN and the peaks were comparable. The crystals were also characterized using the EDXRF. They showed the presence of impurities in the analyte grade and the aquo hydrolysis synthesized salt. We deduced that sodium cyanide synthesized via direct hydrolysis revealed superior purity and possess competitive characteristics when compared with the analyte grade sodium cyanide. This leads to the conclusion that our aim of developing a green, simple and cost-effective synthesis route for producing NaCN was achieved.