Sterols and Sterol Ethoxylates

3 Sterols and Sterol Ethoxylates 3.3.1 Production and Uses of Phytosterols 

In the Kraft pulping process, the steryl esters are largely, although not completely, hydrolysed to free sterols and fatty acids [31]. The sterols are incorporated in the sulfate soap and consequently in the CTO. CTO contains 3-5% of sterols [30], which is a higher concentration than in vegetable oils from annual plants. In distillation of CTO, 

The CMC values of sterol ethoxylates at room temperature are very low, in the range of 3-lOpM, which is much lower than those of corresponding ethoxylated nonylphenols. 

Reprinted from j. Colloid Interface Sci., 213, B. M. Folmer, M. Svensson, K. Holmberg and W. Brown, The physicochemical behavior of phytosterol ethoxylates, 112-120. Copyright 1999, with permission from Elsevier. 

CMC decreases with increasing oxyethylene chain length, contrary to the normal trend for other ethoxylated surfactants. 

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Surface-active compounds can be produced from all wood constituents. For instance, water-soluble cellulose derivatives and lignin, in the form of lignosulfonates, can be used as dispersing agents in many applications. This chapter focuses on the production of resin and fatty acids as well as sterols and sterol ethoxylates as forest-industry by-products, and their use as surface-active components. Moreover, the potential production of hemi-celluloses and their possible utilization as steric stabilizers of oil-in-water emulsions is also outlined. 

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