Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
  • C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
  • C07C5/373—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen with simultaneous isomerisation
  • C07C5/387—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen with simultaneous isomerisation of cyclic compounds containing non six-membered ring to compounds containing a six-membered aromatic ring

Definitions

• Alkylcyclopentanes and gasoline or naphtha fractions containing the-same are dehydroisomerized to aromatic compounds by contacting with a fluorided Group VII-B or VI II metal-alumina catalyst and a carbon oxide as a conversion reaction moderator.
• a fluorided metal-alumina catalyst and a carbon oxide moderator such as carbon monoxide or carbon dioxide
• alkylcyclo pentanes are selectively converted to aromatics and gasoline or naphtha fractions containing the same are upgraded.
• This invention relates to the production of aromatic hydrocarbons from naphthenes and from petroleum fraction containing naphthenes.
• this invention relates to a process for effecting dehydroisomerization of five memberednaphthene ring hydrocarbons to aromatics such as the conversion of methylcyclopentane to benzene.
• Alkylcyclopentanes are found as components of light straight run gasoline and are contained in other gasoline fractions such as naphtha fractions resulting from thermal and catalytic conversion of petroleum. Typically, saturated gasoline or naphtha fractions are treated or up graded to improve their anti-knock characteristics.
• One means of upgrading such streams is by the Well known process of reforming wherein naphthetic hydrocarbons such as cyclohexane compounds are dehydrogenated to aromatics.
• Another object of this invention is to provide a means for upgrading gasoline and naphtha fractions containing alkylcyclopentanes.
• Another object of this invention is the direct production of benzene from methylcyclopentane.
• Yet another object of this invention is to provide a means for converting alkylcyclopentanes to aromatics by 3,756,941 Patented Sept. 4, 1973 Fee employing a catalyst having hydrocracking and hydrogenation activity under processing conditions capable of controlling catalyst activity and selectivity.
• this invention contemplates a process for the dehydroisomerization of al-kylcyclopentanes to aromatic hydrocarbons which comprises contacting a hydrocarbon charge stock containing alkylcyclopentane with a fluorided Group VIIB or VII metal-alumina cataylst in the presence of hydrogen and a carbon oxide wherein the carbon oxide is introduced to said process at the rate of from about 5 10- to 5X10 gram mole of carbon oxide per hour per gram of said catalyst.
• Carbon oxides contemplated herein and introduced in the course of the process include carbon monoxide and carbon dioxide and preferably carbon monoxide.
• dehydroisomerization of alkylcyclopentanes is conducted in a single or continuous reaction stage wherein high conversion of the naphthene is undertaken providing high yields of recoverable liquid product including improved selectivity toward aromatic compounds.
• the dehydroisomerization process described herein is conducted in the presence of a fluorided Group VII-B or VIII metal-alumina catalyst under conversion conditions including temperatures of from about 750 to 1000 F., preferably 850 to 950 F., hydrogen to hydrocarbon mole ratios in the range of about 0.1:1 to 12:1, preferably 0.5:1 to 8:1 and when conducted as a continuous reaction at liquid hourly space velocities of from about 0.5 to 8, preferably 1 to 4.
• the process employs a catalyst comprising a member of Group VII-B or VIII of the Periodic Table, alumina and fluorine and represents a well known class of hydrocracking or reforming catalyst.
• a catalyst comprising a member of Group VII-B or VIII of the Periodic Table, alumina and fluorine and represents a well known class of hydrocracking or reforming catalyst.
• Exemplary of the Gorup VII-B and VIII metals forming a component of the catalyst we mention rhenium, platinum, palladium, rhodium and ruthenium, where the metal or combinations thereof is present in an amount of from about 0.01 to 5.0 weight percent and preferably from about 0.1 to 2.0 weight percent based on the composite catalyst.
• Aluminas in various forms may be used as a component of the catalyst and particularlythose aluminas having replaceable surface hydroxyl groups and surface areas of from S0 to 800 square meters per gram using the BET method.
• alumina we mention for example eta-alumina, gammaalumina, silica-stabilized alumina, i.e., aluminas containing approximately 5 weight percent silica, thoria-alumina,
• the catalyst is provided with additional acidity by virtue of the presence of from about 0.5 to 15.0 weight percent chemically combined fluorine and preferably from 0.5 to 6.0 weight percent.
• the role of our carbon oxide moderator, such as carbon monoxide, in the dehydroisomerization of alkylcyclopentanes and alkylcyclopentane fractions in contact with the aforementioned catalyst and hydrogen is to suppress the cracking aspect of the catalyst by which We mean to interfere with the acidity function of the catalyst surface while at the same time avoiding permanent damage or poisoning of the catalyst.
• our carbon oxide moderator introduced in the course of converting the naphthene to an aromatic strongly shifts the product distribution such that the catalyst is moderated to the extent that the cracking propensity of the catalytic material is inhibited.
• the amount of moderator beneficially employed and introduced in the course of the process varies from about 10 to 5 X gram mole of moderator per hour per gram of catalyst and preferably from about 1 l0- to 2.5 x10" gram mole of moderator per hour per gram of said catalyst.
• the preferred carbon oxide moderator employed in our process is cabon monoxide.
• the rate of carbon oxide introduction is dependent upon the temperature of the reaction such that higher amounts of moderator are required to inhibit cracking at higher temperatures while lesser amounts perform the same function at lower temperatures.
• Amounts such as 7 10- to 1.3 l0 gram mole of moderator per hour per gram of catalyst are suflrcient where the process is carried out at temperatures of about 850 F. whereas higher amounts such as 1.3 10 to 2.3 l0- are needed when processing temperatures are about 925 F.
• carbon oxide introduction and its effect upon the process is responsive to the percent fluorine on the catalyst.
• a catalyst containing lower amounts of fluorine such as 0.5 weight percent requires less carbon oxide to moderate the reaction, whereas fiuorine contents of about 6 weight percent require the higher rates of carbon oxide introduction.
• One convenient means of introducing the moderator to the reaction zone is to add the moderator to the hydrogen stream prior to hydrogen introduction to the reaction chamber. Moderator introduction can be on a continuous basis or alternatively, the carbon oxide may be pulsed or intermittently introduced to the reaction such that the rate of carbon oxide introduction is within the ranges stated above.
• C to C alkylcyclopentanes including for example methylcyclopentane and l,Z-dimethylcyclopentane, alone or in raflinate fractions can be dehydroisomerized in the presence of the catalyst, moderator and conversion conditions recited above to benzene, toluene and xylenes, The conversion is accomplished with minimal cracking such that liquid recoveries of and higher are easily obtained.
• methylcyclopentane is selectively converted to benzene.
• petroleum fractions such as light straight run gasoline having an initial boiling point of about 70 F. and an end point of about 400 F.
• a charge stock comprising commercial methylcyclopentane was contacted with a catalyst comprising 0.5 weight percent platinum on alumina fluorided to a 1 percent level.
• Conversion conditions included reaction temperatures of 800 F. and 850 F., 300 p.s.i.g. of hydrogen flowing at the rate of three cubic feet per hour, a catalyst charge of 85 grams cc.) and the charge stock was introduced at the rate of 100 cc. per hour or a space velocity of 1.0.
• Analysis of the charge stock showed it to contain the following; methylcyclopentane 80.3 percent, hexanes 11.8 percent, benzene 4.6 percent and cyclohexane 3.3 percent.
• Initial conversion was undertaken at temperatures of 800 F. and 850 F. to establish the activity and selectivity of the catalyst and process in the absence of a carbon oxide moderator. Samples were collected after each four hour processing period and analyzed by gas chromatography. Table I summarizes the results for the conversion periods.
• benzene yields are governed by the rate of conversion of methylcyclopentane and the loss of naphthenes to side cracking reaction. Increasing the reaction temperature from 800 F. to 850 F. significantly reduced the amount of recoverable liquid product at increased conversion rates.
• the benzene yield that is the amount of benzene basis the total feed, increased with the higher severity to 38.8%.
• the loss in liquid product of about 20 percent due to cracking became a limiting factor in the attainable benzene yield.
• Example II A charge stock comprising commercial methylcyclopentane mixed with normal heptane indicated on analysis to contain the following: methylcyclopentane 40.1 percent, hexanes 5.9 percent, benzene 2.3 percent, cyclohexane 1.7 percent and normal heptane 50.0 percent.
• the charge stock was contacted with a catalyst comprising 0.5 weight percent platinum on alumina fluorided to a one percent level. Conversion conditions included reaction temperatures of 850 F., 900 F. and 950 F., 250 p.s.i.g. of hydrogen flowing at the rate of 3 cubic feet per hour, a catalyst charge of 100 cc. and the charge stock was introduced at the rate of 100 cc.
• a process .for the dehydroisomerization of alkylcyclopentanes to aromatic'hydrocarbons which comprises contacting a hydrocarbon charge stock containing alkylcyclopentane with a fluorided Group VII-B or VIII metalalumina catalyst wherein said catalyst comprises from about 0.01 to 5.0 weight percent of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium and rhenium in the presence of substantially pure hydrogen and a carbon oxide, wherein said carbon oxide is introduced to said process at the rate of from about 5 X 10* to 5 X 10- gram mole of carbon oxide per hour per gram of said catalyst.
• a process according to claim 1 wherein said contacting is conducted at temperature of from 850 to 950 F.
• a process according to claim 1 wherein said contacting is conducted at a liquid hourly space velocity of from 0.5 to 8.0.
• a process according to claim 1 wherein said catalyst comprises from about 0.5 to 15.0 weight percent fluorine.
• a process according to claim 1 wherein said catalyst comprises from about 0.5 to 6.0 weight percent fluorine.
• hydrocarbon charge stock is a gasoline fraction including alkylcyclopentanes.
• hydrocarbon charge stock is a naphtha fraction containing naphthenes including alkylcyclopentanes.
• alkylcyclopentane has from 6 to 8 carbon atoms.
• alkylcyclopentane is methylcyclopentane and said aromatic hy- 950 F. coupled with increases in moderator levels in drocarbon is benzene.
• alkylcyclopentane is dimethylcyclopentane and said aromatic hydrocarbon is toluene.
• a process for producing benzene which comprises contacting methylcyclopentane with a fluorided Group VII-B or-VIII metal-alumina catalyst wherein said catalyst comprises from about 0.01 to 5.0 weight percent of a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium and rhenium in the presence of substantially pure hydrogen and a carbon oxide, wherein said carbon oxide is introduced to said process of the rate of from about 5 10 to 5 X 10- gram mole of carbon oxide per hour per gram of said catalyst.

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Cited By (1)

• 1971
  • 1971-06-21 US US00155348A patent/US3756941A/en not_active Expired - Lifetime
• 1972
  • 1972-05-19 GB GB2359572A patent/GB1335948A/en not_active Expired
  • 1972-05-22 ZA ZA723483A patent/ZA723483B/xx unknown
  • 1972-05-30 NL NL7207278A patent/NL7207278A/xx unknown
  • 1972-06-02 DE DE19722226935 patent/DE2226935A1/de active Pending
  • 1972-06-12 FR FR7221032A patent/FR2142982B1/fr not_active Expired
  • 1972-06-14 BE BE784878A patent/BE784878A/xx unknown
  • 1972-06-19 CA CA145,114A patent/CA968375A/en not_active Expired
  • 1972-06-19 IT IT25868/72A patent/IT956684B/it active
  • 1972-06-19 BR BR3963/72A patent/BR7203963D0/pt unknown
  • 1972-06-20 SE SE7208130A patent/SE373567B/xx unknown

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