US 7,002,052 B2Granted

Integrated process for producing an alkenyl-substituted aromatic compound

AssigneeDow Global Technologies LLC

InventorsSimon Hamper, William M. Castor, Richard A. Pierce

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Abstract

An integrated process of preparing a C2-5 alkenyl-substituted aromatic compound using a C6-12 aromatic compound and a C2-5 alkane as raw materials. The process involves feeding a C2-5 alkane, for example ethane, and a C2-5 alkyl-substituted aromatic compound, for example ethylbenzene, to a dehydrogenation reactor for concurrent dehydrogenation to a C2-5 alkene, for example ethylene, and a C2-5 alkenyl-substituted aromatic compound, for example stryrene; separating the dehydrogenation effluent to recover a gaseous stream containing alkene, hydrogen, and alkane, and to recover the aromatics with high efficiency; feeding the gas stream and a C6-12 aromatic compound to an alkylation reactor to obtain the corresponding C2-5 alkyl-substituted aromatic compound, which is recycled to the dehydrogenation reactor; subjecting the alkylation unit vent stream containing alkane and hydrogen to a separation step to recover alkane, which is recycled to the dehydrogenation unit; hydrogen, which is recovered at 99% chemical grade purity and energy.

Claims63

Dependent claims

An integrated process of preparing a C2-5 alkenyl-substituted aromatic compound and hydrogen from a C2-5 alkane and a C6-12 aromatic compound, the process comprising:

(a) contacting a C2-5 alkane and a C2-5 alkyl-substituted aromatic compound in a dehydrogenation reactor in the presence of a dehydrogenation catalyst under process conditions sufficient to prepare a dehydrogenation effluent stream comprising a C2-5 alkenyl-substituted aromatic compound, the C2-5 alkyl-substituted aromatic compound, a C2-5 alkene, the C2-5 alkane, and hydrogen;
(b) separating the dehydrogenation effluent stream under conditions sufficient to obtain an essentially non-aromatic, gaseous stream comprising the C2-5 alkene, the C2-5 alkane, and hydrogen, and an aromatics stream comprising the C2-5 alkenyl-substituted aromatic compound and the C2-5 alkyl-substituted aromatic compound, the aromatics recovery being greater than about 90 weight percent;
(c) feeding the essentially non-aromatic gaseous stream comprising C2-5 alkene, C2-5 alkane, and hydrogen into an alkylation reactor wherein the gaseous stream is contacted with a C6-12 aromatic compound in the presence of an alkylation catalyst under process conditions sufficient to prepare an alkylation effluent stream comprising the C2-5 alkyl-substituted aromatic compound, and optionally, poly(C2-5 alkyl-substituted) aromatic compounds(s), and optionally, unreacted C6-12 aromatic compound, and a gaseous stream comprising C2-5 alkane and hydrogen;
(d) separating the alkylation effluent stream under conditions sufficient to recover a C2-5 alkyl-substituted aromatic compound fraction, and optionally, a poly(C2-5 alkyl-substituted) aromatic compound(s) fraction, and optionally, a C6-12 aromatic compound fraction;
(e) recycling the C2-5 alkyl-substituted aromatic compound recovered from steps (b) and (d) into the dehydrogenation reactor of step (a);
(f) separating the gaseous stream comprising C2-5 alkane and hydrogen obtained from step (c) under conditions sufficient to obtain an essentially pure stream of hydrogen and an essentially pure stream of C2-5 alkane;
and
(g) recycling the C2-5 alkane from step (f) into the dehydrogenation reactor of step (a).

5 more elements

An integrated process of preparing styrene from benzene and ethane comprising:

(a) contacting ethane and ethylbenzene in a dehydrogenation reactor in the presence of a dehydrogenation catalyst under process conditions sufficient to prepare a dehydrogenation effluent stream comprising styrene, ethylbenzene, ethane, ethylene, and hydrogen;
(b) separating the dehydrogenation effluent stream under conditions sufficient to obtain an essentially non-aromatic gaseous stream comprising ethylene, ethane, and hydrogen, and an aromatics stream comprising ethylbenzene and styrene, the total aromatics recovery being greater than about 90 weight percent;
(c) feeding the essentially non-aromatic gaseous stream comprising ethylene, ethane, and hydrogen into an alkylation reactor wherein the stream is contacted with benzene in the presence of an alkylation catalyst under process conditions sufficient to prepare an alkylation effluent stream comprising ethylbenzene and, optionally, poly(ethyl)benzenes and unreacted benzene, and an essentially non-aromatic gaseous stream comprising ethane and hydrogen;
(d) separating the alkylation effluent stream under conditions sufficient to recover ethylbenzene and, optionally, polyethylbenzenes and benzene;
(e) recycling the ethylbenzene recovered from steps (b) and (d) into the dehydrogenation reactor of step (a);
(f) separating the essentially non-aromatic, gaseous stream comprising ethane and hydrogen obtained from step (c) under conditions sufficient to obtain an essentially pure stream of hydrogen and an essentially pure stream of ethane;
and
(g) recycling the ethane from step (f) into the dehydrogenation reactor of step (a).

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/181,106Filed 24 Jan 2001 · us provisional application
Priority: 2 Feb 2000
Published: US 2003/0028059 A16 Feb 2003
Granted: 21 Feb 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification31 codes

C07C 15/46
The hydrocarbon substituent containing a carbon-to-carbon double bond: styrene; Ring-alkylated styrenes
C07C 2/66
Addition to a carbon atom of a six-membered aromatic ring: catalytic processes
C07C 5/3332
Catalytic processes: with metal oxides or metal sulfides
C07C 5/3337
With metals: of the platinum group