Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By addition of entire unsaturated molecules – e.g.,...
Patent
1996-10-22
2000-11-07
Dunn, Tom
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By addition of entire unsaturated molecules, e.g.,...
502 67, 502 71, 502 77, C07C 212
Patent
active
061439428
DESCRIPTION:
BRIEF SUMMARY
This invention relates to oligomerization reactions, and to catalysts, more especially to molecular sieve, preferably zeolite, catalysts, and their use in such reactions.
Molecular sieve catalysts of many types have been proposed for use in numerous chemical processes. Among such processes are oligomerization reactions, especially of lower olefins, e.g., alkenes, to higher olefins, e.g., higher alkenes, for example, the oligomerization of C.sub.2 to C.sub.6, especially C.sub.3 and C.sub.4, olefins, to olefins in the C.sub.6 to C.sub.12 range.
GB-A-2106131 describes oligomerizing medium molecular weight .alpha.-olefins, e.g., C.sub.8 to C.sub.14 olefins, to form heavy olefin mixtures comprising trimers, tetramers and pentamers of the starting materials, using intermediate (0.5 to 0.65 nm) pore size zeolites or other molecular sieves as catalysts. As examples of zeolites are given HZSM-5, 11, 12, 21, 23, 35, and 38, and "crystalline admixtures" or physical admixtures of such zeolites, e.g., ZSM-5 and ZSM-11. U.S. Pat. No. 4,417,086 has a similar disclosure.
U.S. Pat. No. 4,324,940 describes, inter alia, the use as an oligomerization catalyst of ZSM-5, selectively oligomerizing smaller rather than larger molecules.
U.S. Pat. No. 4,642,404 describes the activation of an extrudate of the medium pore zeolites listed in GB-A-2106131 with steam and the resulting activity of a ZSM-5 product treated in this way as a propene oligomerization catalyst. U.S. Pat. No. 4,754,096 describes the oligomerization of propene using ZSM-5 to provide lubricant oil range hydrocarbons.
U.S. Pat. No. 4,975,401 describes the advantage of using a mixture of ZSM-5 and ZSM-12 in cracking alkyl-benzenes over the use of either catalyst alone.
U.S. Pat. No. 5,177,282 describes oligomerization of an olefin by passing it over two molecular sieves in series before being contacted with a Ni-containing catalyst; in an example ethene is passed first over a 0.3 nm pore size sieve, then over a Type 13X molecular sieve.
EP-A-293914 describes crystalline admixtures and physical mixtures of various molecular sieves and their use in oligomizeration of olefins; in one example the catalytic activities of a SAPO-11/AlPO.sub.4 -11 composite and physical mixtures of the two sieves are compared.
U.S. Pat. No. 4,919,896 describes the use of series reactors for oligomizeration of olefins; a number of different zeolites are proposed as catalysts.
U.S. Pat. No. 4,032,432 relates primarily to cracking, but light ends withdrawn from the reactor are contacted with a catalyst comprising a mixture of larger pore, e.g., faujasite, and smaller pore, e.g., mordenite, erionite or ZSM-5, zeolites.
U.S. Pat. No. 4,247,416 describes the preparation of ZSM-25 and mentions the possibility of its being incorporated in another unspecified zeolite as matrix.
All prior published proposals for olefin oligomerization have their advantages and disadvantages, the latter including an insufficient ability to control the extent of oligomerization. For example, in the oligomerization of propene, if ZSM-5 is employed as catalyst, the oligomer product contains a relatively low proportion of dimer, and higher proportions of trimer, tetramer and pentamer. If ZSM-22 is employed as catalyst, the dimer is by far the major product. However, in neither case is the yield of trimer high. If, therefore, the desired product is one with a high nonene content neither catalyst offers an attractive route.
The present invention is based on the observation that the product obtained when oligomerization is carried out over a catalyst comprising at least two molecular sieves contains a higher proportion of a certain oligomeric species than is obtainable by carrying out the reaction over any one of the zeolite species alone.
In a first aspect, the invention provides a process for the oligomerization of an olefin, which comprises contacting under oligomerization conditions a feed comprising at least one olefin with a catalyst comprising at least one molecular sieve having a refined constraint index (as hereina
REFERENCES:
patent: 3702886 (1972-11-01), Argauer
patent: 4032432 (1977-06-01), Owen
patent: 4247416 (1981-01-01), Doherty et al.
patent: 4324940 (1982-04-01), Dessau
patent: 4417086 (1983-11-01), Miller
patent: 4481177 (1984-11-01), Valyocsik
patent: 4556477 (1985-12-01), Dwyer
patent: 4642404 (1987-02-01), Shihabi
patent: 4754096 (1988-06-01), Chang et al.
patent: 4919896 (1990-04-01), Harandi et al.
patent: 4973781 (1990-11-01), Valyocsik et al.
patent: 4975401 (1990-12-01), Kaeding et al.
patent: 5177282 (1993-01-01), Nierlich et al.
patent: 5243112 (1993-09-01), Chester et al.
patent: 5278114 (1994-01-01), Wielers et al.
"Estimation of the void structure and pore dimensions of molecular sieve zeolites using the hydroconversion of n-decane," Martens et al., Zeolites, vol. 4, pp. 98-107, Apr., 1984.
"Exploration of the void size and structure of zeolites and molecular sieves using chemical reactions," , Pure & Appl. Chem. , vol. 58, No. 10, pp. 1329-1338, 1986.
Martens Luc Roger Marc
Verrelst Wim Herman
Collins Douglas J.
Dunn Tom
Exxon Chemical Patents Inc.
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