The hydroxyl groups can be changed into esters, ethers, acetals and ketals, etc.
最常用的羟基保护基可归纳为三类：酯类、醚类和缩醛或缩酮类。
2
This paper examined the cellulose esters and cellulose ethers application in pharmaceutical coatings and reviewed their structure-property relations and researching aspects in recent yeas.
结合近年来国内外研究现状，综述了天然纤维的化学结构、性能及在医药辅料领域的应用方向。
3
A total of 48 components in UCR were identified, including hydrocarbons (31 kinds), alcohols (6 kinds), aldehydes (4 kinds), ethers ( 1 kinds), esters (3 kinds) and other components (3 kinds).