酰化反应在250mL碘量瓶中进行，用水浴加热（50±1oC），完成一次测定时间可以缩短至1个小时。
The acylation reaction is completed in a 250 mL iodine flask which was heated in a water bath ( 50oC ) . It takes about an hour to determine the hydroxyl value for one sample .
碘量瓶