Welcome to Chemistry and Industry of Forest Products,

›› 2008, Vol. 28 ›› Issue (5): 100-104.

• 研究报告 • Previous Articles     Next Articles

Preparation of Bleached Low-chlorine Shellac by Catalytic Hydrogenation and Its Structural Characterization

LIAO Ya-long, CHAI Xi-juan   

  1. Faculty of Material & Metallurgical Engineering, Kunming University of Science & Technology, Kunming 650093, China
  • Received:2008-01-07 Revised:1900-01-01 Online:2008-10-30 Published:2008-10-30

Abstract: Bleached natural shellac with low chlorine content, which had been widely used in food industry and pharmacy, was prepared and characterized. The bleached natural shellac product with low chlorine content was prepared by means of catalytic hydrogenation of the bleached shellac in the presence of Ni-Fe binary-metal catalyst and hydrogen. Most of chlorine bonded to the double bond of terpenic acids of shellac and compacted in the molecule of shellac were eliminated by sodium hypochlorite bleaching under the conditions of Ni content 2.91%, catalyst quantity 8 g/L, H2 flow rate 50 mL/min, and reaction temperature 90℃ for 240 min. Moreover, the mechanism of catalytic hydrogenation in preparation of the products was elucidated by the aid of structure characterization of the products through elementary analysis, infrared spectrometry, and ultraviolet spectrophotometry. It was demonstrated that chlorine content in the final product could reach 0.44% under optimum conditions, chlorine content in the final product was 1/5 of that before dechlorination by catalytic hydrogenation, and chlorine compacted in the molecule of shellac was substituted by hydrogen.

Key words: catalytic hydrogenation, binary metal, dechlorination, bleached shellac, characterization

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