A Study On The Synthesis Process And The Catalyst For The Preparation Of Alkyl Polyglycosides And Cyanoethyl Starch

The method for sythesis of alkyl polyglycosides from glucose , caprylic alcohol ( or lauryl alcohol ) by the catalyst of heteropoly acids have been studied. The influences of the catalysts and the operating condition for this synthesis on the yield of the product have been investigatied also. In addition the synthesis of cyanoethyl starch and its properties have been studied. the results obstained are summaried as follows:1. Comparing with H₂SO₄, 4-methylbenzenesulfonic acid ,H₃PW₁₂O₄₀ catalyst is a better catalyst for synthesie of APG. The color of APG prepared by this method is very light ,the yield of undesired carbohydrate polymer side products arc very low and the reaction temperature is lower.2. The results showed that the compound catalyst H₃PW₁₂O₄₀ +strong acidic resin +zeolite is a new catalyst for the preparation of APG. It not only has a higher activity, but also reduces the amount of H₃PW₁₂O₄₀ in this catalyst. The properties of APG obtained are very well. The optimal ratio of the compound catalyst is H₃PW₁₂O₄₀ / acidic resin / zeolite = 1 /1 /1 .3. The key step for the synthsis of APG is the way how to add glucosein the reacter. The results showed that using the way adding glucose step by step the yield of APG can be resaised remarkably.4. The optimal condition for synthsis of APG include temperature, presure, reaction time , ratio of material are 90℃, 20mmHg, 5h, alcohol/glucose >105. The condition for preparation of cyanothyl starch have been studied. The optimal reaction condition was got, these are temperature: 50 ℃, NaOH /starch=3/5, reaction time :5h, acylonitrile/starch=3/1 The results also showed that the higher thedegree of substitution of cyanoethyl starch is ,the better the properties of insulation, dissolusion and transparency.