A method for preparing a catalyst composition suitable for increasing the fluorine content in a hydrocarbon or a halogenated hydrocarbon is disclosed. The method involves (a) co-precipitating a solid by adding ammonium hydroxide to an aqueous solution of a soluble trivalent chromium salt and a soluble salt of a modifier metal selected from silver and palladium, that contains at least three moles of nitrate (i.e., NO
3
−
) per mole of chromium (i.e., Cr
+3
) in the solution and has a modifier metal concentration of from about 0.05 atom % to about 10 atom % of the total concentration of modifier metal and chromium in the solution to form an aqueous mixture containing co-precipitated solid and dissolved ammonium nitrate; and after at least three moles of ammonium hydroxide per mole of chromium in the solution has been added to the solution, (b) drying said aqueous mixture formed in (a); and (c) calcining the dried solid formed in (b) in an atmosphere containing at least 10% oxygen by volume (e.g., air). Also disclosed is a catalyst composition comprising alpha-chromium oxide and a modifier metal selected from silver and palladium prepared by the above method. Also disclosed is a process for increasing the fluorine content in a hydrocarbon or halogenated hydrocarbon in the presence of a catalyst; and processes using a catalyst composition comprising chromium, oxygen and a modifier metal selected from siver and palladium as essential constituent elements (e.g., a catalyst composition prepared by the above process). An azeotropic composition involving CF
3
CCl═CF
2
and HF is also disclosed.
本发明公开了一种制备催化剂组成物的方法,适用于提高碳氢化合物或卤化碳氢化合物中
氟含量。该方法包括(a)通过向可溶性三价
铬盐和可溶性修饰
金属盐的
水溶液中添加氢氧化
铵,共沉淀出固体,所述
水溶液中含有至少每摩尔
铬(即Cr+3)三摩尔
硝酸盐(即
NO3−)和约0.05原子%至约10原子%的修饰
金属总浓度,形成含有共沉淀固体和溶解的
硝酸铵的
水混合物;并在向溶液中加入至少每摩尔
铬三摩尔氢氧化
铵后,(b)干燥(a)中形成的
水混合物;和(c)在至少含有10%体积
氧气的气氛中(例如空气)煅烧(b)中形成的干燥固体。本发明还公开了一种催化剂组成物,包括α-
铬氧化物和从
银和
钯中选择的修饰
金属,由上述方法制备。本发明还公开了一种在催化剂存在下提高碳氢化合物或卤化碳氢化合物中
氟含量的过程;以及使用包括
铬,氧和从
银和
钯中选择的修饰
金属作为必要组成元素的催化剂组成物的过程(例如,由上述过程制备的催化剂组成物)。本发明还公开了涉及CF3CCl═
CF2和HF的共沸混合物组成。