Decolorization Process Of Natural Alpha-tocopherol

The discoloration of natural -tocopherol by adsorption was studied. Two processes were employed: stirred tank process and fixed bed process. They are all successful, and can be used according to product color specifications.In the experiments of stirred tank process, six factors were studied: adsorbent, solvent, temperature, concentration, contact time and amount of adsorbent. The results showed that when one type of activated carbon (Shanghai 1#, powdered) was selected as adsorbent, ethanol as solvent, at operating conditions of temperature 10 , concentration 0.1 g/ml, amount of adsorbent 0.2 g per gram raw material and adsorption time 2 h, the product color reached the lightest (from Gardner 17# to 15.2#). The recovery of a -tocopherol was 97.5%.In the experiments of fixed bed process, when one type of activated carbon (Shanghai 0#, granular) was selected as adsorbent and ethanol as solvent, at operating conditions of temperature 30癈, concentration 0.1 g/ml, contact time 1-2 h, at a capacity of 0.37 g/ml bed volume, the product color was less than Gardner 13.5#, part of product could reach a color of less than Gardner 9#. The recovery of a -tocopherol was 93.75%.In the fixed bed process, the activated carbon can be regenerated by using 0.5 mole/1 potassium hydroxide ethanol solution and 5% acetic acid ethanol solution. The discoloring ability of the activated carbon had not decreased after three times regeneration.According to the breakthrough curve of product color under 30 and 0.1 g/ml. an equation has been correlated between the product color and the amount of rawmaterials throughput.