Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650? C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

The present invention provides a process for preparing 2,3,3,3-tetrafluoropropene from 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane, comprising the following steps: (a) catalytic reaction of 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane with HF into a reaction mixture comprising HCl, 2-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, unreacted HF, and optionally 1,1,1,2,2-pentafluoropropane; (b) separating the reaction mixture into a first stream comprising HCl and 2,3,3,3-tetrafluoropropene and a second stream comprising HF, 2-chloro-3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane; (c) catalytic reaction of the second stream into a reaction mixture comprising 2,3,3,3-tetrafluoropropene, HCl, unreacted 2-chloro-3,3,3-trifluoropropene, unreacted HF and optionally 1,1,1,2,2-pentafluoropropane and (d) feeding the reaction mixture of step (c) directly without separation to step (a).

The preparation of chlorinated hydrocarbons by reacting a chlorinated alkane substrate, such as 1,1,1,3-tetrachloropropane, with a source of chlorine, such as chlorine (Cl.sub.2), in the presence of a polyvalent molybdenum compound, such as molybdenum pentachloride, is described. With the method of the present invention, the chlorinated alkane product has covalently bonded thereto at least one more chlorine group than the chlorinated alkane substrate, and the chlorinated alkane substrate and the chlorinated alkane product each have a carbon backbone structure that is in each case the same.

The preparation of chlorinated hydrocarbons by reacting a chlorinated alkane substrate, such as 1,1,1,3-tetrachloropropane, with a source of chlorine, such as chlorine (Cl.sub.2), in the presence of a polyvalent molybdenum compound, such as molybdenum pentachloride, is described. With the method of the present invention, the chlorinated alkane product has covalently bonded thereto at least one more chlorine group than the chlorinated alkane substrate, and the chlorinated alkane substrate and the chlorinated alkane product each have a carbon backbone structure that is in each case the same.

The present invention relates to a process for preparing 1,1,1-trifluoro-2,3-dichloropropane which comprises contacting chlorine with 3,3,3-trifluoropropene in the presence of a catalyst to form 1,1,1-trifluoro-2,3-dichloropropane, wherein the catalyst comprises at least one metal halide, where the metal is a metal from Group 13, 14 or 15 of the periodic table or a transition metal or combination thereof.

The present invention relates to a process for preparing 1,1,1-trifluoro-2,3-dichloropropane which comprises contacting chlorine with 3,3,3-trifluoropropene in the presence of a catalyst to form 1,1,1-trifluoro-2,3-dichloropropane, wherein the catalyst comprises at least one metal halide, where the metal is a metal from Group 13, 14 or 15 of the periodic table or a transition metal or combination thereof.

The present invention provides a process for preparing 2,3,3,3-tetrafluoropropene from 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane, comprising the following steps: (a) catalytic reaction of 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane with HF into a reaction mixture comprising HCl, 2-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, unreacted HF, and optionally 1,1,1,2,2-pentafluoropropane; (b) separating the reaction mixture into a first stream comprising HCl and 2,3,3,3-tetrafluoropropene and a second stream comprising HF, 2-chloro-3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane; (c) catalytic reaction of the second stream into a reaction mixture comprising 2,3,3,3-tetrafluoropropene, HCl, unreacted 2-chloro-3,3,3-trifluoropropene, unreacted HF and optionally 1,1,1,2,2-pentafluoropropane and (d) feeding the reaction mixture of step (c) directly without separation to step (a).

The present invention provides a process for preparing 2,3,3,3-tetrafluoropropene from 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane, comprising the following steps: (a) catalytic reaction of 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane with HF into a reaction mixture comprising HCl, 2-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, unreacted HF, and optionally 1,1,1,2,2-pentafluoropropane; (b) separating the reaction mixture into a first stream comprising HCl and 2,3,3,3-tetrafluoropropene and a second stream comprising HF, 2-chloro-3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane; (c) catalytic reaction of the second stream into a reaction mixture comprising 2,3,3,3-tetrafluoropropene, HCl, unreacted 2-chloro-3,3,3-trifluoropropene, unreacted HF and optionally 1,1,1,2,2-pentafluoropropane and (d) feeding the reaction mixture of step (c) directly without separation to step (a).

X-Ray photoelectron spectroscopy (XPS) is used to assess or predict the catalytic activity of a chromium oxyfluoride catalyst in a reaction wherein a chlorinated compound is converted to a fluorinated compound.

X-Ray photoelectron spectroscopy (XPS) is used to assess or predict the catalytic activity of a chromium oxyfluoride catalyst in a reaction wherein a chlorinated compound is converted to a fluorinated compound.