US3907916A — Dehydrogenation of alkyl aromatic hydrocarbons

Claim 1

Independent Claim 141 words

IN A METHOD OF ACTIVATING SELF-REGENATIVE DEHYDROGENATION CATALYST USEFUL FOR DEHYDROGENATING ALKYL AROMATIC HYDROCARBONS HAVING FROM 1 TO 2 SIX MEMBERED RINGS AND FROM 1 TO 2 ALKYL GROUPS OF 2-3 C ATOMS TO THE CORRESPONDING ALKENYL AROMATIC HYDROCARBON, BY PASSING A MIXTURE OF STEAM AND SAID ALKYL AROMATIC HYDROCARBON OVER SAID CATALYST AT A TEMPERATURE OF FROM ABOUT 600* TO ABOUT 700*C THE UMPROVEMENT COMPRISING INTERRUPTING THE FEED OF TE SAID ALKYL ARO MATIC HYDROCARBON AND CONTAINING THE FEED OF STEAM AT THE SAID TEMPERATURE FOR A PERIOD OF 7-30 MINUTES EACH 24-48 HOURS WITH LITTLE OR NO CARBON OXIDE EFFLUENCE DURING THE ACTIVATION CYCLE TO PROVIDE A CATALYST A TIVATION CYCLE, RESUMING THE FEED OF SAID ALKYL AROMATIC HYDROCARBON FOR DEHYDROGENATION THEREOF UNDER HIGH SEVERITY REACTION CONDITIONS, AND REPEATING SAID ACTIVATION CYCLES AND SAID ALKYL AROMATIC HYDROCARBON DEHYDROGENATION CYCLES.

Claim 2

Dependent Claim 141 words

IN A METHOD OF ACTIVATING SELF-REGENATIVE DEHYDROGENATION CATALYST USEFUL FOR DEHYDROGENATING ALKYL AROMATIC HYDROCARBONS HAVING FROM 1 TO 2 SIX MEMBERED RINGS AND FROM 1 TO 2 ALKYL GROUPS OF 2-3 C ATOMS TO THE CORRESPONDING ALKENYL AROMATIC HYDROCARBON, BY PASSING A MIXTURE OF STEAM AND SAID ALKYL AROMATIC HYDROCARBON OVER SAID CATALYST AT A TEMPERATURE OF FROM ABOUT 600* TO ABOUT 700*C THE UMPROVEMENT COMPRISING INTERRUPTING THE FEED OF TE SAID ALKYL ARO MATIC HYDROCARBON AND CONTAINING THE FEED OF STEAM AT THE SAID TEMPERATURE FOR A PERIOD OF 7-30 MINUTES EACH 24-48 HOURS WITH LITTLE OR NO CARBON OXIDE EFFLUENCE DURING THE ACTIVATION CYCLE TO PROVIDE A CATALYST A TIVATION CYCLE, RESUMING THE FEED OF SAID ALKYL AROMATIC HYDROCARBON FOR DEHYDROGENATION THEREOF UNDER HIGH SEVERITY REACTION CONDITIONS, AND REPEATING SAID ACTIVATION CYCLES AND SAID ALKYL AROMATIC HYDROCARBON DEHYDROGENATION CYCLES.

Claim 3

Dependent Claim 31 words

The method of claim 1 in which the catalyst has a weight ratio of hydrated iron oxide and anhydrous iron oxide of 1:4 to 17:20 and about 13:7 to 4:1, respectively.

Claim 4

Dependent Claim 47 words

The method of claim 1 in which the catalyst contains from about 62.5 to about 87.9% by weight of Fe2O3, from about 2 to about 2.5% by weight of Cr2O3 and from about 9.6 to about 35.3% by weight of at least one of K2O or K2CO3.

Claim 5

Dependent Claim 16 words

The method of claim 3 in which the catalyst contains about 3.5% by weight of V2O5.

Claim 6

Dependent Claim 86 words

The method of claim 1 in which the catalyst contains from about 24.8 to 30% by weight each of Fe2O3 and ZnO, from about 5 to about 30% by weight of potassium oxide, hydroxide or carbonate, from about 5 to about 10% by weight of an oxide of copper, cadmium, thorium or silver, from about 5 to about 10% by weight of an alkali metal chromate, from about 1 to about 5% by weight of a refractory cement and a small amount of A carbonaceous material.

Claim 7

Dependent Claim 142 words

In a method of dehydrogenating an alkyl aromatic hydrocarbon having from 1 to 2 six membered rings and from 1 to 2 alkyl groups of from 2 to 3 C atoms each and a total of 8 to 14 C atoms in said hydrocarbon, in the presence of steam, at a temperature of from about 600* to about 700*C., by passing a mixture of the steam and said hydrocarbon over a self-regenerative catalyst, the improvement comprising, interrupting the flow of the alkyl aromatic hydrocarbon while continuing the flow of steam at the said temperature for a period of from 7 to about 30 minutes during each 24-48 hours, then resuming the flow of alkyl aromatic hydrocarbon and repeating the steps of interrupting the flow of said alkyl aromatic hydrocarbon and continuing the flow of steam for said 7-30 minutes each 24-48 hours.

Claim 8

Dependent Claim 142 words

In a method of dehydrogenating an alkyl aromatic hydrocarbon having from 1 to 2 six membered rings and from 1 to 2 alkyl groups of from 2 to 3 C atoms each and a total of 8 to 14 C atoms in said hydrocarbon, in the presence of steam, at a temperature of from about 600* to about 700*C., by passing a mixture of the steam and said hydrocarbon over a self-regenerative catalyst, the improvement comprising, interrupting the flow of the alkyl aromatic hydrocarbon while continuing the flow of steam at the said temperature for a period of from 7 to about 30 minutes during each 24-48 hours, then resuming the flow of alkyl aromatic hydrocarbon and repeating the steps of interrupting the flow of said alkyl aromatic hydrocarbon and continuing the flow of steam for said 7-30 minutes each 24-48 hours.

Claim 9

Dependent Claim 34 words

The method of claim 6 in which the alkyl aromatic hydrocarbon is ethyl toluene, and the feed during dehydrogenation contains from 1.5 to 3 parts by weight of steam per part of said hydrocarbon.

Claim 10

Dependent Claim 16 words

The method of claim 7 in which the steam to hydrocarbon ratio is 1.7 to 1.

Claim 11

Dependent Claim 70 words

The method of claim 7 in which the steam to hydrocarbon ratio is 3 to 1, the dehydrogenation temperature is 620*-640*C., the liquid hourly space velocity is about 0.3, the steaming period is of about 15 minutes duration each 24 hours, and the catalyst contains 24.81% by weight of Fe2O3, 24.1% of ZnO, 22.5% K2CO3, 7.44% Cu2O, 7.44% Na2Cr2O7 3.9% alumina cement, 4% methyl cellulose and 5.1% graphite before calcining.

Claim 12

Dependent Claim 29 words

The method of claim 6 in which the alkyl aromatic hydrocarbon is ethyl benzene and feed during dehydrogenation contains 0.4 to 1 part of steam per part of hydrocarbon.

Claim 13

Dependent Claim 31 words

The method of claim 6 in which the alkyl aromatic hydrocarbon is diethyl benzene and the feed during dehydrogenation contains from 1.5 to 6 parts of steam per part of hydrocarbon.

Claim 14

Dependent Claim 32 words

The method of claim 6 in which the alkyl aromatic hydrocarbon is isopropyl benzene and the feed during the dehydrogenation step contains 0.4 to 1.5 parts of steam per part of hydrocarbon.

Claim 15

Dependent Claim 33 words

The method of claim 6 in which the alkyl aromatic hydrocarbon is ethyl biphenyl and the feed during the dehydrogenation step contains from 0.8 to 2 parts of steam per part of hydrocarbon.

Claim 16

Dependent Claim 21 words

The method of claim 6 in which temperature during the catalyst steaming step is about the same as the dehydrogenation temperature.

Claim 17

Dependent Claim 20 words

The method of claim 10 in which the catalyst contains 87.9% by weight of Fe2O3, 2.5% Cr2O3 and 9.0% K2O.

Claim 18

Dependent Claim 22 words

The method of claim 10 in which the catalyst contains 74.5% by weight of Fe2O3, 2.0% Cr2O3, 20.0% K2CO3 and 3.5% V2O5.

Claim 19

Dependent Claim 20 words

The method of claim 10 in which the catalyst contains 62.5% by weight of Fe2O3, 2.2% Cr2O3, and 35.3% K2CO3.

Claim 20

Dependent Claim 35 words

The method of claim 10 in which the catalyst contains 23.6% by weight of ferric oxide hydrate, 35.3% anhydrous ferric oxide, 16.7% K2CO3, 2.5% K2Cr2O7, 2.5% V2O5, 2.8% cement, 8.3% methyl cellulose, and 8.3% graphite.

Claim 21

Dependent Claim 34 words

The method of claim 12 in which the catalyst contains 24.81% by weight of Fe2O3, 24.81% ZnO, 22.5% K2CO3, 7.44% Cu2O, 7.44% Na2Cr2O7, 3.9% alumina cement, 4% methyl cellulose and 5.1% graphite before calcining.

Claim 22

Dependent Claim 20 words

The method of claim 11 in which the catalyst contains 87.9% by weight of Fe2O3, 2.5% Cr2O3 and 9.0% K2O.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-09-22	1979-03-24	1979-09-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-09-22	1983-03-24	1983-09-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-09-22	1987-03-24	1987-09-23	$7700.00	Window Closed / Lapsed

Dehydrogenation of alkyl aromatic hydrocarbons

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