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游离磷酸作为硅藻土磷酸盐固体酸催化剂， 用于催化丙烯齐聚和其他反应。采用了离子色谱 （ Ｉ Ｃ）、 Ｈａｍ ｍ ｅｔｔ ｐ Ｈ 指示剂法和 Ｎａ Ｏ Ｈ 溶液化学滴定法， 研究了催化剂中游离磷酸的数量和组成与催化剂活性的关系。结果表明， 游离磷酸由 ５％ —３５％ 正磷酸 （ Ｈ３ Ｐ Ｏ４）、１％ —７％ 焦磷酸 （ Ｈ４ Ｐ２ Ｏ７） 和＜ １％ 的多聚磷酸组成。它直接影响催化剂的酸强度分布。含有 ８％ —１５％ Ｈ３ Ｐ Ｏ４和 ２％ —５％ Ｈ４ Ｐ２ Ｏ７ 的催化剂具有一定数量的中、高强度酸中心， 故其丙烯齐聚催化活性高。
Free phosphoric acid is used as a diatomaceous earth phosphate acid solid catalyst to catalyze the oligomerization of propylene and other reactions. Ion chromatography (I C), Hamm ett p H indicator method and Na O H solution chemical titration were used to study the relationship between the amount and composition of free phosphoric acid in the catalyst and the catalyst activity. The results show that free phosphoric acid consists of 5% -35% orthophosphoric acid (H3P04), 1% -7% pyrophosphoric acid (H4 P2 O7) and <1% polyphosphoric acid. It directly affects the acid strength distribution of the catalyst. Catalysts containing 8% -15% H3P04 and 2% -5% H4P2O7 have a number of medium- and high-strength acid sites and therefore have high propylene oligomerization catalytic activity.