Lewis Acids: From Conventional Homogeneous to Green Homogeneous and Heterogeneous Catalysis

Organic catalysis over zeolites: A perspective on reaction paths within micropores

Shape-selective catalysis in zeolites

Inorganic molecular sieves: Preparation, modification and industrial application in catalytic processes

In this review, a brief survey is offered on the main nanotechnology synthetic approaches available to heterogeneous catalysis, and a few examples are provided of their usefulness for such applications. We start by discussing the use of colloidal, reverse micelle, and dendrimer chemistry in the production of active metal and metal oxide nanoparticles with well-defined sizes, shapes, and compositions, as a way to control the surface atomic ensembles available for selective catalysis. Next we introduce the use of sol–gel and atomic layer deposition chemistry for the production and modification of high-surface-area supports and active phases. Reference is then made to the more complex active sites that can be created or carved on such supports by using organic structure-directing agents. We follow with an examination of the ability to achieve multiple functionality in catalysis via the design of dumbbells, core@shell, and other complex nanostructures. Finally, we consider the mixed molecular-nanostructure approach that can be used to develop more demanding catalytic sites, by derivatizing the surface of solids or tethering or immobilizing homogeneous catalysts or other chemical functionalities. We conclude with a personal and critical perspective on the importance of fully exploiting the synergies between nanotechnology and surface science to optimize the search for new catalysts and catalytic processes.

Nanostructured materials for applications in heterogeneous catalysis

A process for producing substantially linear hydrocarbons by oligomerizing a lower olefin at elevated temperature and pressure which comprises contacting the lower olefin under oligomerization/polymerization conditions with siliceous acidic ZSM-23 zeolite having Bronsted acid activity; wherein the zeolite has acidic pore activity and wherein the zeolite surface is rendered substantially inactive for acidic reactions. The zeolite surface can be neutralized by a bulky pyridine compound having an effective cross-section larger than the zeolite pore. The preferred deactivating agent is 2,4,6-collidine, which may be applied to the zeolite as a pretreatment or added with olefin feed in a continuous process. The olefin oligomers may be used as alkylating agents to prepare biodegradable alkylbenzenes and alkylphenylsulfonates. A preferred catalyst for this alkylation reaction is dealuminized mordenite.

Olefin oligomerization with surface modified zeolite catalyst

There is provided an improved process for the vapor phase oxidation of alkanes to dicarboxylic acidanhydrides, particularly butane to maleic anhydride, which comprises using a vanadiumphosphorus-oxygen complex catalyst having a P/V atomic ratio of 0.5-2, promoted or modified with certain transition metals, preferably zirconium, chromium, iron or hafnium. Using these catalysts, the oxidation process can be carried out at lower temperatures and increased yield as compared to the unpromoted complex.

Oxidation of alkanes to maleic anhydride using promoted vanadium-phosphorus catalyst

Para-Disubstituted aromatics are produced in the presence of a catalyst comprising zeolite ZSM-48 Selective cracking of para-isomers may also be accomplished to produce mixtures rich in meta-isomers

Selective production and reaction of p-Disubstituted aromatics over zeolite ZSM-48

A process for the selective alkylation of substituted or unsubstituted benzene compounds with relatively long chain length alkylating agents to produce phenylalkanes having an improved yield of the 2-phenylkane isomer. The reaction is carried out in the presence of crystalline zeolite catalysts characterized by channels or networks of pores having openings with a major dimension of 6-7 angstroms.

Preparation of 2-phenylalkanes

A process for converting a methanol feed to light olefins over a zeolite catalyst comprising at least some crystalline aluminosilicate zeolitic material having a Constraint Index of about 1 to 12 and a silica/alumina mole ratio of at least about 12, e.g., ZSM-5, in the presence of diluent which provides O 2 -containing gas, e.g. air, in the reaction zone under methanol conversion conditions. By using such a ZSM-5 type zeolite catalyst and an oxygen-providing diluent, methanol can be converted to an olefin-containing hydrocarbon product enriched in C 2 to C 4 olefins such as ethylene.

Lewis B. Young

Papers

Olefin oligomerization with surface modified zeolite catalyst

Oxidation of alkanes to maleic anhydride using promoted vanadium-phosphorus catalyst

Selective production and reaction of p-Disubstituted aromatics over zeolite ZSM-48

Preparation of 2-phenylalkanes

Catalytic conversion of methanol to light olefins