sorbitol, also known as sorbitol. it is white hygroscopic powder or crystalline powder, flakes or granules, odorless. depending on the crystallization conditions, the melting point changes in the range of 88~102℃, and the relative density is about 1.49. easily soluble in water (1g dissolves in about 0.45ml water), slightly soluble in ethanol and acetic acid. it has a refreshing sweetness, the sweetness is about half that of sucrose, and its caloric value is similar to that of sucrose. according to the understanding of sorbitol supply: in the food industry, sorbitol liquid with a content of 69~71% is mostly used. sorbitol liquid is a clear, colorless, syrupy liquid with a sweet taste, neutral to litmus, and miscible with water, glycerin and propylene glycol. can be used as nutritive sweetener, humectant, chelating agent and stabilizer.
several synthesis methods of sorbitol:
1. add the prepared 53% glucose aqueous solution to the autoclave, and add 0.1% of glucose by weight. nickel catalyst. after replacing the air, hydrogenation is carried out under conditions of about 3.5mpa, 150°c, and ph 8.2-8.4, and the end point is controlled to keep the residual sugar below 0.5%.
after precipitation for 5 minutes, the resulting sorbitol solution is refined through ion exchange resin. raw material consumption quota: hydrochloric acid 19kg/t, liquid alkali 36kg/t, solid alkali 6kg/t, aluminum-nickel alloy powder 3kg/t, oral sugar 518kg/t, activated carbon 4kg/t.
2. it is produced by using refined glucose obtained from starch saccharification and medium-pressure continuous or intermittent hydrogenation.
3. add 53% glucose aqueous solution (ph=8.2~8.4 with alkali solution in advance) and 0.1% glucose mass nickel-aluminum catalyst into the autoclave, exhaust the air and proceed with the reaction, and control the temperature. 150℃, pressure 3.5mpa. when the glucose content reaches below 0.5%, the reaction reaches the end point. leave to settle and filter. the filtrate is refined with strong acidic styrene-based cation exchange resin 001×7 and strong alkaline ammonium type i anion exchange resin 201×7 to remove impurities such as nickel and iron to obtain the finished product d-sorbitol.
