Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By addition of entire unsaturated molecules – e.g.,...
Patent
1995-11-14
1999-05-04
Langel, Wayne
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By addition of entire unsaturated molecules, e.g.,...
502 66, 502 74, 502161, 502162, 585513, 585514, 585651, B01J 3118, C07C 224, C07C 226
Patent
active
059005211
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to catalysts supported on inorganic carriers, for producing ethylene which is used in basic reactions including polymerization, copolymerization and polycondensation reactions in the petrochemical industry and fine chemicals industry, and preparation of the catalysts having the following formula:
In Ma,Pc/S formula (I), M is a compound selected from the group consisting of RuCl.sub.2 (PPh.sub.3).sub.3, RuCl.sub.2 (CO).sub.2 (PPh.sub.3).sub.2, Ru.sub.3 (CO).sub.12, RhCl(CO)(PPh.sub.3).sub.2, IrCl(CO)(PPh.sub.3).sub.2, Pd(PPh.sub.3).sub.4, Pt(PPh.sub.3).sub.4 and RuCl.sub.3.xH.sub.2 O; S is an inorganic carrier selected from the group consisting of .alpha.-Al.sub.2 O.sub.3, .gamma.-Al.sub.2 O.sub.3, SiO.sub.2, SiO.sub.2 -Al.sub.2 O.sub.3, Y-zeolite, MgO and TiO.sub.2 ; P is a promoter selected from the group consisting of PPh.sub.3, P(OCH.sub.3).sub.3, P(OC.sub.2 H.sub.5).sub.3 and P(O)(OC.sub.2 H.sub.5).sub.3 ; a is the amount of metal in the catalyst in weight percent, ranging from 0.25 to 5 wt %; and c is the amount of promoter in the catalyst in weight percent, ranging from 1.0 to 20.0 weight percent.
Further, the present invention provides a new process for the preparation of ethylene by directly converting methane or purified natural gas, in the presence of the above catalyst with nitrogen, at a temperature of about 670 to 850.degree. C., preferably in the range of 710 to 810.degree. C., which is a distinctly lower reaction temperature compared to that used for the conventional synthesis of hydrocarbon(s) by dehydrogenation. By the process of the present invention, ethylene is obtained in a short time, with a high yield, and without by-products, such as CO, CO.sub.2, contrary to oxidative coupling reactions where oxygen is introduced.
BACKGROUND
There are very few processes known in the art which use a catalyst to produce ethylene by direct conversion of methane; moreover, what is known is in a different technical field from the present invention. In conventional processes, large amounts of by-product such as carbon dioxide are produced, separation and removal thereof is difficult and environmental pollution is likely to be caused. Also, synthesis of hydrocarbon(s) by conventional dehydrogenation is conducted at relatively high temperatures, i.e., about 1500 to 1550.degree. C. via thermal or electric cracking reactions which require a high energy supply, expensive high temperature equipment (plan), as well as running at an enormous loss of thermal energy, which is costly, such as severe corrosion of the reactor.
Various patents which describe synthesis of hydrocarbon(s) by oxidative coupling or dehydrogenation reactions, include U.S. Pat. Nos. 5066629, 5068486 and 5118654, Canadian Patent No. 2016675 and Japanese Patent Nos. 04352730, 04368342.
SUMMARY OF THE INVENTION
Until now, new catalysts being able to conduct conversion reaction not at so (ultra) high temperature as that in process for synthesis of hydrocarbons by dehydrogenation but at distinctly lower (mid.low) temperature, and new process for producing said catalyst, and new process for conversion into ethylene using said catalyst have always been expected.
To meet the expectations above, resulting from years of study, the inventors have developed a new catalyst and a simple process for obtaining ethylene in a short time, with high yield and with trace amounts of impurities, by converting methane or purified natural gas in the presence of said catalyst at distinctly lower temperatures compared to that used for the synthesis of hydrocarbon(s) by dehydrogenation or oxidative coupling reactions. Thus, by the present invention, the direct conversion of methane carried out at distinctly low temperatures enables costs associated with enormous amounts of thermal energy that was needed in the synthesis of hydrocarbon(s) by dehydrogenation or oxidative coupling reactions to be saved, and minimizes environmental pollution by reducing the amount of impurities, namely CO.sub.2, produced. By the p
REFERENCES:
patent: 4255283 (1981-03-01), Bartek et al.
patent: 5105053 (1992-04-01), Jacobson et al.
patent: 5177294 (1993-01-01), Siriwardane
Ahn Pyung Kwon
Park Dae Chul
Korean Research Institute of Chemical Technology
Langel Wayne
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