Olefin Oligomerization Using Delaminated Zeolite Supports As Catalyst (Chevron)

CATEGORY: ZEOLITES: OLEFIN OLIGOMERIZATION 
Olefin Oligomerization Using Delaminated Zeolite Supports As Catalyst (Chevron)
United States Patent Application 20160122258
Zhan; Bi-Zeng ;   et al.   May 5, 2016
Assignee: Chevron U.S.A.
Abstract
Provided is an improved process for olefin oligomerization allowing one to realize superior selectivity. The process comprises contacting a hydrocarbon feed comprised of straight and branched chain olefins under oligomerization conditions with a catalyst comprising delaminated SSZ-70. The delaminated SSZ-70 offers a zeolite layer with a single unit cell of thickness in one dimension, allowing for elimination of mass transfer in comparison with regular SSZ-70. The result is superior selectivity.
FIELD OF THE INVENTION
[0002] The present invention relates to delaminated zeolites and their use as catalysts in the hydroprocessing of hydrocarbons. More specifically, the present invention relates to the use of delaminated SSZ-70 as a catalyst in liquid olefin oligomerization.
BACKGROUND
[0003] Zeolites are widely used as acidic catalysts for refining applications attributed to their unique and uniform pore structure with sizes in the sub-nanometer range. The pore sizes of zeolites dictate reaction of refining processes including hydroisomerization, hydrocracking, olefin alkylation and olefin oligomerization, thus dictate reaction selectivity. However, hydroprocessing products often experience varying degree of continuously (over)cracking when they diffuse out of nanometer-scaled zeolitic channels. Thus elimination of these types of side-reactions is significant for efficiency improvement. One of the solutions for preventing overcracking is reduction of acidic strength. But this approach reduces catalyst activity at the same time.
[0004] A. Corma et al. in "Delaminated zeolite precursors as selective acidic catalysts", Nature, vol. 396, November 1998, pp 353-356, discusses delaminating MCM-22(P), the precursor of both MCM-22 and ERB-1 zeolites. The delaminated zeolite is designated ITQ-2, and was shown to have catalytic potential.
[0005] Molecular sieve SSZ-70 is known and is discussed in "Physiochemical Properties and Catalytic Behavior of the Molecular Sieve SSZ-70", Archer et al. Chemistry of Materials, 2010, vol. 22, pp 2563-2572. A method for the synthesis of the SSZ-70 is discussed. Pure silica, borosilicate and aluminosilicate SSZ-70 materials were prepared and characterized. The catalytic activity of Al-SSZ-70 materials was tested using the CI (Constraint Index) test. U.S. Pat. Nos. 7,108,843 and 7,550,073 also discuss the synthesis of the molecular sieve SSZ-70, and its use in hydrocarbon conversion processes such as hydrocracking. The disclosure of both U.S. Pat. Nos. 7,108,843 and 7,550,073 are expressly incorporated herein by reference in their entirety.
[0006] It would be of great value to the hydroprocessing industry if a more effective and selective olefin oligomerization process were discovered.
SUMMARY
[0007] Provided is a process involving the oligomerization of liquid olefins in the presence of a delaminated SSZ-70 catalyst. The delaminated SSZ-70 has been found to provide unexpected improvements in the catalysis of hydroprocessing hydrocarbons. It has been found that delaminated SSZ-70 offers a zeolite layer with a single unit cell of thickness in one dimension, allowing an elimination of mass transfer in comparison with regular SSZ-70 (non-delaminated). It also provides the possibility of eliminating the spatial constraint on oligomerized product to meet some specific applications. For example, significant improvement of selectivity to larger molecules with boiling point in the range of base oil (e.g. 600.degree. F.+) is believed possible in olefin oligomerization when using a delaminated SSZ-70 catalyst with acidic sites located on the external surface compared to regular SSZ-70.
[0008] Among other factors, it has been discovered that using a catalyst comprising delaminated SSZ-70 as a catalyst in an olefin oligomerization process, particularly liquid olefin oligomerization, superior selectivity can be realized. A more effective process for preparing base oils is achieved, as significant improvement of selectivity to larger molecules with a boiling point in the 600.degree. F.+ range is possible.
Free Full Text Source:  http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=10&f=G&l=50&co1=AND&d=PG01&s1=chevron.AS.&OS=AN/chevron&RS=AN/chevron