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 invention provides a catalyst system comprising: a) one or more Group 1 metal phosphotungstate-containing species; and b) one or more catalytic species suitable for hydrogenation; and a process for the preparation of monoethylene glycol from starting material comprising one or more saccharides, by contacting said starting material with hydrogen in a reactor in the presence of a solvent and said catalyst system.

The invention provides a catalyst system comprising: a) one or more Group 1 metal phosphotungstate-containing species; and b) one or more catalytic species suitable for hydrogenation; and a process for the preparation of monoethylene glycol from starting material comprising one or more saccharides, by contacting said starting material with hydrogen in a reactor in the presence of a solvent and said catalyst system.

The present invention provides a process for the preparation of ethene by vapor phase chemical dehydration of a feed-stream comprising ethanol and optionally water and/or ethoxy ethane, said process comprising contacting a dried supported heteropolyacid catalyst in a reactor with the feed-stream having a feed temperature of at least 200? C.; wherein before the supported heteropolyacid catalyst is contacted with the feed-stream having a feed temperature of at least 200? C., the process is initiated by: (i) drying a supported heteropolyacid catalyst in a reactor under a stream of inert gas having a feed temperature of from above 100? C. to 200? C.; and (ii) contacting the dried supported heteropolyacid catalyst with an ethanol-containing vapor stream having a feed temperature of from above 100? C. to 160? C.

The present invention provides a process for the preparation of ethene by vapor phase chemical dehydration of a feed-stream comprising ethanol and optionally water and/or ethoxy ethane, said process comprising contacting a dried supported heteropolyacid catalyst in a reactor with the feed-stream having a feed temperature of at least 200? C.; wherein before the supported heteropolyacid catalyst is contacted with the feed-stream having a feed temperature of at least 200? C., the process is initiated by: (i) drying a supported heteropolyacid catalyst in a reactor under a stream of inert gas having a feed temperature of from above 100? C. to 200? C.; and (ii) contacting the dried supported heteropolyacid catalyst with an ethanol-containing vapor stream having a feed temperature of from above 100? C. to 160? C.

The invention provides a catalyst system comprising: a) one or more silver tungstate-containing species; and b) one or more catalytic species suitable for hydrogenation, wherein the weight ratio of said one or more silver tungstate-containing species to the one or more catalytic species suitable for hydrogenation is greater than 2.5:1, on the basis of the total weight of the catalyst system; and a process for the preparation of monoethylene glycol from starting material comprising one or more saccharides, by contacting said starting material with hydrogen in a reactor at a reactor temperature in the range of from 145 to 190 C. in the presence of a solvent and said catalyst system.

The invention provides a catalyst system comprising: a) one or more silver tungstate-containing species; and b) one or more catalytic species suitable for hydrogenation, wherein the weight ratio of said one or more silver tungstate-containing species to the one or more catalytic species suitable for hydrogenation is greater than 2.5:1, on the basis of the total weight of the catalyst system; and a process for the preparation of monoethylene glycol from starting material comprising one or more saccharides, by contacting said starting material with hydrogen in a reactor at a reactor temperature in the range of from 145 to 190 C. in the presence of a solvent and said catalyst system.

The invention relates to the preparation of a catalyst containing: a mainly aluminum oxide calcined support; a hydro-dehydrogenating active phase containing at least one metal of group VIB,
the process including:
a) a first precipitation step of at least one basic precursor and at least one acidic precursor,
b) a heating step,
c) a second precipitation step by addition to the suspension of at least one basic precursor and at least one acidic precursor,
d) a filtration step;
e) a drying step,
f) a moulding step,
g) a heat treatment step;
h) an impregnation step of the hydro-dehydrogenating active phase on the support obtained in the step g).

The invention relates to the preparation of a catalyst containing: a mainly aluminum oxide calcined support; a hydro-dehydrogenating active phase containing at least one metal of group VIB,
the process including:
a) a first precipitation step of at least one basic precursor and at least one acidic precursor,
b) a heating step,
c) a second precipitation step by addition to the suspension of at least one basic precursor and at least one acidic precursor,
d) a filtration step;
e) a drying step,
f) a moulding step,
g) a heat treatment step;
h) an impregnation step of the hydro-dehydrogenating active phase on the support obtained in the step g).

The invention provides a catalyst system comprising: a) one or more sodium metatungstate-containing species; and b) one or more catalytic species suitable for hydrogenation; and a process for the preparation of monoethylene glycol from starting material comprising one or more saccharides, by contacting said starting material with hydrogen in a reactor in the presence of a solvent and said catalyst system.