Elf-union

Elf France

Daniel Duprez

Michel Grand

A water dealkylation catalyst of aromatic hydrocarbons containing at least one metal of Group VIII and eventually, one metal of group VII.sub.b deposited on a gamma alumina of special properties containing at least 1000 ppm of sulfate ions having undergone a pre-treatment in aqueous medium at a pH between 1 and 10 at a temperature below 100.degree. C. The catalysts contain rhodium on pre-treated gamma alumina and the bimetallic catalysts contain 2 metals of the group VIII or one metal of the group VII and one metal of the group VII.sub.b on pre-treated gamma alumina.

Catalysts for water dealkylation of aromatic hydrocarbons

A process for the catalytic conversion of aromatic fractions additionally containing variable proportions of C.sub.5 to C.sub.11 non-aromatic hydrocarbons, to obtain substantially pure benzene and hydrogen, by water dealkylation of the aromatic hydrocarbons and simultaneous reforming of the non-aromatic hydrocarbons, characterized in that aromatic fractions having boiling points which may be varied depending on the yield of hydrogen desired, are treated by steam at temperatures from 350.degree. C. to 600.degree. C., at a pressure of 1 to 80 bars, a volume of liquid passed per unit volume of catalyst of 0.1 to 10 and a water/hydrocarbon charge flow rate ratio of 0.2 to 4, in the presence of a dealkylation catalyst selected from at least one group VIII metal, on a support selected from a sieve L, a pretreated gamma alumina, and a mixed spinel (M.sub.x M'.sub.1-x) Al.sub.2 O.sub.4, M being a non-noble group VIII metal, and M' being selected from the group consisting of magnesium, manganese, and copper.

Catalytic conversion of aromatic fractions in the presence of steam

Catalyst for water dealkylation of oil fractions containing monoalkylated or polyalkylated aromatic hydrocarbons, said catalyst containing at least one metal of group VIII in a proportion of 0.1 to 5% by weight on a carrier, characterized in that said carrier is a zeolite L that can be exchanged with either alkaline cations or polyvalent cations of groups V.sub.b, VI.sub.b and VII.sub.b. The zeolite L can be exchanged with a solution of metals such as lithium, sodium, caesium, chromium, manganese, and rhodium. A method of using the catalyst by contacting the hydrocarbons with the catalyst at a temperature of 400.degree.-600.degree. C., a pressure of 0-80 bars, a space velocity of the hydrocarbon of from 0.1 to 10h.sup.-1, and a water to hydrocarbon mol ratio of 2-20.

Water dealkylation catalyst of aromatic hydrocarbons

Water dealkylation catalysts of petroleum fractions containing monoalkylated or polyalkylated aromatic hydrocarbons including at least one metal of group VIII deposited in a proportion of from 0.1 to 5% by weight on a spinel, and having deposited in a proportion of from 0.1 to 5% by weight on a spinel, and having improved properties of activity, selectivity and stability, characterized in that the carrier is a mixed spinel of the formula (M.sub.x M'.sub.1-x)Al.sub.2 O.sub.4 wherein M is a bivalent base metal of group VIII such as nickel, iron and cobalt and M' is a bivalent metal belonging to groups 2a, 7b, 1b or 2b such as magnesium, manganese, copper and zinc. The mol. ratio M/M' may vary from 0.5:1 to 50:1, preferably from 1:1 to 20:1.

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Poitiers, France

Daniel Duprez