Synthesis And Process Optimization Of Arbutin

Arbutin firstly is found in the leaves of Arctostapylos Bearberry.The appearance of arbutin is white needle crystal or powder.Arbutin has many pharmacological activities,such as anti-inflammation and anti-bacterial actions.In addition,the researchers found that arbutin could effectively inhibit reversible the activity of tyrosinase as a competitive inhibitor.Tyrosinase is the key catalyst in accelerating the formation of melanin.So it has the role of whitening the skin,but also for the skin without irritation,toxic side effects.In this paper,the syntheis of arbutin is studied.Glucose and hydroquinone are primary materials.And arbutin is synthesized through protection,condensation and deacetylation.Anhydrous glucose and excess acetic anhydride react to get pentaacetyl glucose,the molar ratio is 1:9.5,the yield is 70.0%.The addition of sodium sulfite in the reaction,the molar ratio of hydroquinone and ethanoic anhydride is 1:1,the yield is up to 52%.The condensation reaction complies with the principle of Helferich reaction.In this paper,ethyl ether boron trifluoride is selected as the catalyst,the catalyst dosage is adjusted to control the reaction rate,and the yield is 79.0%.Finally,the arbutin is got by removing the acetyl in the presence of sodium methylate,and the yield is 80.0%.Intermediate product crystallization is the key to the synthesis of arbutin product.A breakthrough is that crystallization in ethanol to obtain high purity monoacetyl p-benzenediol,GC content is more than 90%.Arbutin is mainly used in pharmaceutical and cosmetic fields,it has very high requirements on the quality of the product.The white needle crystal is got by crystallizing in the wet ethyl acetate.The melting point is 199 ~202?,HPLC content is more than 99.5%,the product reaches to pharmaceutical and cosmetic requirements.The synthesis steps are short,the raw materials are used as chemical raw materials,the reaction condition is mild,the operation is simple and safe,the product quality is good,the total yield is 34.0%,which is suitable for industrial production.