单宁酸

单宁酸

CAS号:1401-55-4
英文名:Tannic acid
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化合物简介
Tannic acid is a specific commercial form of tannin, a type of polyphenol. Its weak acidity (pKa around 10) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which corresponds with decagalloyl glucose, but in fact it is a mixture of polygalloyl glucoses or polygalloyl quinic acid esters with the number of galloyl moieties per molecule ranging from 2 up to 12 depending on the plant source used to extract the tannic acid. Commercial tannic acid is usually extracted from any of the following plant part: Tara pods (Caesalpinia spinosa), gallnuts from Rhus semialata or Quercus infectoria or Sicilian Sumac leaves (Rhus coriaria).
基本信息
编号系统
物化性质
安全信息
生产方法及用途
生产方法
1.将精萘10
0 kg投入磺化釜中,升温至125℃,在搅拌下加入浓硫酸120kg,在155~165℃下反应6~8h。取样测终点,如果完全溶于水则证明磺化完全。逐渐降温至110℃,加少量水稀释。在80℃左右将料液压入缩合釜。在70℃左右滴加37%的甲醛水溶液39kg,滴毕后在80~90℃下反应3h,得青黑色粘稠液即为成品。 制取方法:
2.五倍子粉碎后加4倍量热水于40~50℃温浸24h。滤出浸出液,加水冷却至5~8℃,加活性炭脱色过滤,滤液经过强酸性阴离子交换树脂除去无机盐。洗脱液浓缩后趁热倾入90%~95%乙醇,冷后过滤,滤液浓缩至干即为鞣酸成品。
用途
澄清剂、增涩剂、粗油脱臭剂、助香剂;单宁酸可用于鞣革、墨水制造、纸张和丝绸上胶、锅炉除垢等,还可作媒染剂、啤酒和葡萄酒的澄明剂、橡胶的凝结剂等。可用于用于印染、冶金、医药等工业,单宁酸本身毒性很低。铍、铝、镓、铟、铌、钽和锆的沉淀和重量测定。铜、铁、钒、铈和钴的比定测定。蛋白质及生物碱的沉淀剂。钼酸铵滴定铅时的外指示剂。染料媒染剂。