Preliminary Study on Production of Furfural by Pre-hydrolysis of Hard Wood

Abstract

The purpose of this experiment is to examine the possibility of production of furfural by pre-hydrolysis at sulphite cooking of hard wood. Pre-hydrolysis was carried out by using sulphrous acid (Total acid 5 %) and cooking was done by using of Ca-base sulphite cooking liquor (T.A. 7.5 %, C.A. 1.5 %) The influences of pre-hydrolysis conditions on dissolution of pentosans and pulp qualities were observed.Results were as follows : (1) Yield, screening residue, and chlorine demand of unbleached pulp become suddenly make inferior, when the temperature of pre-hydrolysis rises over 110°C.(2) On analytical values of bleached pulp, the remarkable differences between 100°C and 110°C, don't appear.(3) Clogging values of the viscose by emulsion xantation method are made inferior by pre-hydrolysis, but this inferiority is almost prevent, if we use the lower temperature than 110°C as the temperature of pre-hydrolysis.(4) The dissolution of pentosans from chip increases by the raising of temperature and prolongation of time at pre-hydrolysis.(5) To obtain as much as possible the furfural, without injuring the reactivity and analytical values of pulp, the lower temperature and longer time in pre-hydrolysis should be recommended.(6) The loss of pentosan in pre-hydrolysis (the difference between the dissoluted pentosan calculated from the pentosan content of pre-hydrolysis chip and the dissoluted pentosan directly measured from the spent liquor of pre-hydrolysis) slightly increases with the rising of temperature in pre-hydrolysis.(7) It is considered that the production of furfural will be compatible with the production of dissolving pulp, if we select the suitable conditions of pre-hydrolysis, even in sulphite cooking of hard wood.And then, we can expect that the 5-6 furfural per weight of wood may be obtained without injuring the reactsvity of pulp.