Process for producing alkylated hydroxyl-containing aromatic...

Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing

Reexamination Certificate

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C568S766000, C568S785000, C568S786000, C568S788000, C568S790000, C568S791000, C568S793000

Reexamination Certificate

active

06670513

ABSTRACT:

The present invention relates to a process for alkylation of an aromatic compound having at least one hydroxyl group on the aromatic ring, such as phenol, catechol, anisole, cresol, resorcinol or mixtures thereof, to provide an aromatic product having both hydroxyl and alkyl groups on the same aromatic ring in which the content of the para-alkyl isomer is high. The alkylated products are useful in making detergents for lubricating oils.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a process for producing alkylated, hydroxyl-containing aromatic compounds, said process comprising:
(a) isomerizing a normal alpha-olefin or mixture of normal alpha-olefins having from about 16 to about 30 carbon atoms in the presence of a first acidic catalyst capable of inducing both olefin isomerization and skeletal isomerization to produce a mixture of isomerized olefins;
(b) alkylating a hydroxyl-containing aromatic compound with said mixture of isomerized olefins in the presence of a second acidic catalyst comprising a sulfonic acid resin catalyst or an acidic clay.
Also provided in accordance with this invention is a process for producing an alkylated hydroxyl-containing aromatic compound, said process comprising:
(a) isomerizing a normal alpha-olefin or mixture of normal alpha-olefins having from about 16 to about 30 carbon atoms in the presence of a first acidic catalyst capable of inducing both olefin isomerization and skeletal isomerization to produce a mixture of straight-chain and branched-chain isomerized olefins;
(b) alkylating an hydroxyl-containing aromatic compound selected from the group consisting of phenol, catechol, anisole, cresol, resorcinol and mixtures thereof with said mixture of isomerized olefins in the presence of a second solid, acidic catalyst comprising a sulfonic acid resin catalyst or an acidic clay.
Among other factors, the present invention is based on the discovery that olefin and skeletal isomerization of the normal alpha-olefin prior to alkylation of the hydroxyl-containing aromatic compound results in an alkylated product containing a high content of compounds in which the alkyl and hydroxyl groups are in the para position relative to each other.
DETAILED DESCRIPTION OF THE INVENTION
In its broadest aspect, the present invention involves a process for producing alkylated aromatic compounds that have at least one hydroxyl and at least one alkyl group on the same aromatic ring. That process comprises isomerizing a normal alpha-olefin or mixture of normal alpha-olefins (referred to herein collectively as “NAO”) having from about 16 to about 30 carbon atoms in the presence of a first solid, acidic catalyst capable of inducing both olefin isomerization and skeletal isomerization to produce a mixture of isomerized olefins, then alkylating an aromatic compound having at least one hydroxyl group on the aromatic ring with the mixture of isomerized olefins in the presence of a second solid, acidic catalyst comprising a sulfonic acid resin catalyst or an acidic clay.
The alkylation of phenol with olefins, under normal alkylation conditions using a macroporous sulfonic acid resin catalyst or acidic clay, nominally affords an alkylated phenol product in which the para and ortho isomers are dominant. When one uses a normal alpha-olefin to alkylate the phenol, the para isomer/ortho isomer ratio content is only about 50/50.
It has now been discovered that by isomerizing an NAO prior to using it to alkylate phenol (or other hydroxyl-containing aromatic compounds), a significant increase in the para isomer is obtained in the alkylated product, e.g., the para isomer/ortho isomer ratio can be increased to about 80/20. The alkylated product can be used to prepare detergents for lubricating oil, and the high para-isomer content allows more base to be added to the detergent.
AROMATIC COMPOUNDS CONTAINING AT LEAST ONE HYDROXYL GROUP ON THE AROMATIC RING
The hydroxyl-containing aromatic compounds that are alkylated in the subject process include phenol, catechol, anisole, cresol, resorcinol and mixtures thereof, with phenol being the preferred compound.
NORMAL ALPHA-OLEFINS
The normal alpha-olefins that are isomerized prior to the alkylation of the hydroxyl-containing aromatic compounds are normal alpha-olefins or mixtures of normal alpha-olefins that have from about 16 to about 30 carbon atoms per molecule. Preferably, they have about 20 to about 28 carbon atoms per molecule.
OLEFIN ISOMERIZATION CATALYST
The catalyst used to isomerize the normal alpha-olefin or mixture of normal alpha-olefins can be any catalyst that is capable of inducing both olefin isomerization and skeletal isomerization in the NAO while leaving the NAO otherwise essentially in tact. As used herein, the term “olefin isomerization” refers to movement of the carbon-carbon double bond within the molecule, and the term “skeletal isomerization” refers to rearrangement of the carbon atoms within the molecule. Examples of such catalysts include solid, acidic catalysts comprising at least one metal oxide, and having an average pore size of less than 5.5 Angstroms. Preferably, the solid, acidic catalyst comprises a molecular sieve with a one-dimensional pore system. More preferably, it is selected from the group consisting of molecular sieves SM-3, MAPO-11, SAPO-11, SSZ-32, ZSM-23, MAPO-39, SAPO-39, ZSM-22, and SSZ-20. The preferred molecular sieves are SAPO-11 and SSZ-32. Other possible solid, acidic catalysts useful for isomerization include molecular sieves ZSM-35, SUZ4, NU-23, NU-87, and natural or synthetic ferrierites. These molecular sieves are well known in the art and are discussed in Rosemarie Szostak's Handbook of Molecular Sieves (New York, Van Nostrand Reinhold, 1992), and U.S. Pat. No. 5,282,958, issued Feb. 1, 1994 to Santilli et al., both of which are hereby incorporated by reference.
The catalyst can be an admixture with at least one Group VIII metal. Preferably, the Group. VIII metal is selected from the group consisting of at least one of platinum and palladium, and optionally other catalytically active metals such as molybdenum, nickel, vanadium, tungsten, cobalt, zinc and mixtures thereof. More preferably, the Group VIII metal is selected from the group consisting of at least one of platinum and palladium. The amount of metal ranges from about 0.01% to about 10% by weight of the catalyst (not counting the weight of the metal), preferably from about 0.2% to about 5% by weight of the catalyst. The techniques of introducing catalytically active metals to the catalyst are disclosed in the literature, and pre-existing metal incorporation techniques and treatment of the catalyst to form an active catalyst such as ion exchange, impregnation or occlusion during preparation of the catalyst are suitable. Such techniques are disclosed in U.S. Pat. Nos. 3,236,761; 3,226,339; 3,236,762; 3,620,960; 3,373,109; 4,202,996; 4,440,996 and 4,710,485 which are incorporated herein by reference.
The “metal” or “active metal” as used herein means one or more metals in the elemental state or in some form such as sulfide, oxide or mixtures thereof. Regardless of the state in which the metallic component actually exists, the concentrations are computed as if they existed in the elemental state.
The catalyst is used in an amount effective to catalyze the isomerization reaction.
OLEFIN ISOMERIZATION PROCESS CONDITIONS
A preferred method of isomerizing the normal alpha-olefin or mixture of normal alpha-olefins involves catalytic isomerization using, for instance, a platinum-supported-on-SAPO-11 molecular sieve catalyst to partially isomerize a feed containing the NAO. This and related catalysts are described in U.S. Pat. No. 5,082,986, issued Jan. 21, 1992 to Miller, which is hereby incorporated by reference.
For platinum-on-SAPO-11 catalysts, partial isomerization is preferred. Therefore, preferred operating conditions include weight hourly space velocities (WHSV) between about 0.5 and about 10 at temperatures between about 100° C. and about 250° C. More preferred conditions include

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