Abstract: To develop a method for large-scale extraction of l-quebrachitol from natural rubber serum.Membrane separation technology was applied to concentrate and purify the natural rubber serum in the experiments,and the L-quebrachitol was extracted from the serum concentrate by crystallization.The crude extract was recrystallized three times from distilled water,and then high purity sample was prepared by solventing-out process.The ultrafiltration (UF) membrane with a molecular weight cut-off (MWCO) of 1000 Daltons can reject most of the organic matters in the skim serum.The UF permeate was concentrated by nanofiltration (NF) membrane,and L-quebrachitol was crystallized easily from the concentrate.As a result,a new and convenient approach for large scale extraction of L-quebrachitol was proposed combining membrane separation and crystallization.In addition,80g sample can be extracted for each operation with this approach under laboratory conditions.The structure of L-quebrachitol was confirmed by elementary analysis,infrared (IR) spectroscopy,nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy (MS).

Key words: natural rubber, L-quebrachitol, serum, membrane technology, crystallization