Beta zeolite catalyst

A. Corma, S. Iborra, S. Miquel, and J. Primo, Preparation of long-chain alkyl glucoside surfactants by one-step direct Fischer glucosidation, and by transace-talation of butyl glucosides, on beta zeolite catalysts, /. Catal., 180 (1998) 218-224. 

The Beta-zeolite catalyst samples were purchased from PQ Corporation and from UOP. The HF-treated p-zeolite and montmorillonite clay samples were prepared as described previously (9,12). 

Han, M.. hi, X., fin, S., Intrinsic kinetics of the alkylation of benzene with propylene over beta zeolite catalyst, Kinet. Catal., 42 (4), 533-538, 2001... 

A Simple Method for the Preparation of Active Ti Beta Zeolite Catalysts... 

While the structure of beta was being investigated, new uses for this zeolite were being discovered. A major breakthrough came in late 1988 when workers at Chevron invented a liquid phase alkylation process using beta zeolite catalyst. Chevron patented the process in 1990. While Chevron had significant commercial experience with the use of Y (FAU) zeolite in liquid phase aromatic alkylation. Chevron quickly recognized the benefits of beta over Y as well and other... 

Because new high-acfivify befa zeolife cafalysfs such as QZ-2000 catalyst are such strong acids, they can be used at lower reaction temperatures than SPA catalyst or other relatively lower-activity zeolites such as MCM-22 catalyst. The lower reaction temperature in turn reduces the olefin oligomerization reaction rate, which is relatively high for SPA catalyst. The result is that beta zeolite catalysts tend to have higher selectivity to cumene and lower selectivity to both nonaromatics that distill with cumene (such as olefins, which are analyzed as Bromine Index, and saturates) and heavy by-products. For example, although butyl-benzene is typically produced from traces of butylene... 

Beta zeolite catalyst is also an extremely effective catalyst for the transalkylation of DIPB to produce cumene. Because of the high activity of beta zeolite, transalkylation promoted by beta zeolite can take place at very low temperature to achieve high conversion and minimum side products such as heavy aromatics and additional -propylbenzene as highlighted in Fig. 6. Virtually no tri-isopropyl benzene is produced in the beta system owing to the shape selectivity of the three-dimensional beta zeolite structure, which inhibits compounds heavier than DIPB from forming. 

Beta zeolite catalyst can be optimized to nearly eliminate all undesirable side reactions in the production of cumene. The improvement in beta zeolite catalyst quality has occurred to the point that any significant impurities in the cumene product are governed largely by trace impurities in the feeds. The selectivity of the catalyst typically reduces by-products to a level resulting in production of ultrahigh cumene product purities up to 99.97 wt%. At this level, the only significant byproduct is n-propylbenzene with the catalyst producing essentially no EB, butylbenzene, or cymene beyond precursors in the feed. Fig. 7 shows the reactions of some common feedstock impurities that produce these cumene impurities. 

Water can act in this environment as a Bronsted base to neutralize some of the weaker zeolite acid sites. This effect is not harmful to any appreciable extent to the beta zeolite catalyst at typical feed stock moisture levels and under normal alkylation and transalkylation conditions. This includes processing of feedstocks up to the normal water saturation condition (typically 500-1000 ppm) resulting in 10-150 ppm water in the feed to the alkylation reactor dependent on feed and/or recycle stream fractionation efficiency. 

Small quantities of methanol and ethanol are sometimes added to the C3S in pipelines to protect against freezing because of hydrate formation. Although the beta zeolite catalyst is tolerant of these alcohols, removing them from the feed by a water wash may still be desirable to achieve the lowest possible levels of EB or cymene in the cumene product. Cymene is formed by the alkylation of toluene with propylene. The toluene may already be present as an impurity in the benzene feed, or it may be formed in the alkylation reactor from methanol and benzene. Ethylbenzene is primarily formed from ethylene impurities in the propylene feed. However, similar to cymene, EB can also be formed from ethanol. 

Sulfur has no significant effect on beta zeolite catalyst at the levels normally present in olefin and benzene feeds considered for cumene production. However, even though the beta zeolite catalyst is sulfur tolerant, trace sulfur that makes its way into the finished cumene unit product may be a feed quality concern for downstream phenol processors where the typical sulfur specification is <1 ppm. The majority of sulfur compounds associated with propylene (mercaptans) and those associated with benzene (thiophenes) are converted to by-products outside the boiling range of cumene. Because some sulfur compounds form... 

Use of beta zeolite catalyst does not require the benzene feed to be clay treated prior to use in alkylation service. Some of the unsaturated material in the benzene can lead to the formation in the alkylation reactors of polycyclic-aromatic material which will get preferentially trapped in some zeolites having relatively small-sized pores. This can lead to increased deactivation rates in such small-pore zeolites. Beta zeolite s large pore structure makes it possible to more easily handle this polycyclic-aromatic material and as a result does not require further treatment of the benzene feed to remove unsaturated material. In addition, alpha-methylstyrene (AMS) is produced by alkylation of benzene with methylacetylene or propadiene. Some of the AMS alkylates with benzene, forming diphenyl-propane, a heavy aromatic that leaves the unit with the DIPB column bottoms. 

From a commercial standpoint this knowledge has had the additional benefit of developing a regeneration protocol that is extremely robust. It has been demonstrated in commercial in situ and ex situ procedures that the beta zeolite catalyst can be regenerated with excellent results providing complete restoration of fresh catalyst performance. The feature of complete regenerability is another attribute that distinguishes beta zeolite catalysts... 

Long-Term Stability of Beta Zeolite Catalyst... 

A good example of the ruggedness of the beta zeolite catalyst can be found in the case of JLM s Blue Island (Illinois) Q-Max operation. The operation started in August 1996 as the first Q-Max process operation with UQP beta zeolite catalyst. Initial operating results were reported in 1997. The unit has continued to operate with stable performance for more than 7 yr without catalyst regeneration in spite of the presence of significant levels of feed contaminants. 

Excellent monoalkylation selectivity has also been observed over many years of service in the JLM operation as shown in Fig. 10. Under the normal operating conditions of the unit, an equilibrium cumene selectivity of about 91 mol% is predicted. Thus, results clearly show that the beta zeolite catalyst is active enough to achieve near-equilibrium selectivity. This is an important feature of the catalyst as the amount of dialkylate that must be processed in the transalkylator and the subsequent cost of processing this material are minimized. 

Taking advantage of the in situ regeneration capability, the customer opted to regenerate the catalyst three times during this period. The results show the remarkable resilience of the beta zeolite catalyst to the stresses of regeneration with virtually no loss in monoalkylate selectivity or cumene product quality as a result of repeated regenerations. 

P-16 - Isomerization of /f-butane over small crystals of H-Beta and Pt-H-Beta zeolite catalysts... 

V. H. Tillu, D. K. Dumbre, R. D. Wakharkar, V. R. Choudhary, Tetrahedron Lett. 2011, 52, 863-866. One-pot three-component Kabachnik-Fields synthesis of a-aminophosphonates using H-beta zeolite catalyst. 

Lopez-Fonseca R, Gutierrez-Ortiz JI, Gonzdlez-Velasco JR. Catalytic Combustion of Chlorinated Hydrocarbons Over H-BETA and PdO/H-BETA Zeolite Catalysts. Appl Catal A Gen 2004 271 39-46. 

Lopez-Fonseca, R., Gutierrez-Ortiz, J., Gutierrez-Ortiz, M., et al. (2005). Catalytic oxidation of aliphatic chlorinated volatile organic compounds over Pt/H-BETA zeolite catalyst under dry and humid conditions, Catal. Today, 107, pp. 200-207. 

Previously, Kantam et al. also carried out the Friedel-Crafts acylation of pyrrole with acetic anhydride over microcrystalline beta zeolites with less successful results [118]. The microcrystalline beta zeolite catalysts showed the highest activity in the acylation reaction due to their higher acidity as compared with ordinary beta zeolite. When a microcrystalline beta zeolite I (with a particle size of 1-10 gm obtained by mechanical disintegration of beta zeolite) was used as catalyst, 73% of conversion and 58% of selectivity to 2-acetylp5n role was reached after 2.5 h of reaction time. However, when a microcrystalline beta zeolite II (with a particle size of 10-50 gm obtained by decreasing the aging time to 48 h instead of 1 week) was used, 78% of conversion and 64% of selectivity to 2-acetylpyrrole was reached after 2h of reachon time. 

Cobalt on Beta zeolite catalysts [96] demonstrated a bifunctional character with the maximum activity at a specific concentration of the metal and particle size. The selectivity was strongly influenced by the zeolite Beta acidity, which promotes the formation of isoparaffins at 220°C, unlike conventional zeolites revealing a poor isomerization activity at this temperature. This difference was explained by the small size of Beta zeolite crystallites. 

This is relatively the most intense area of research in exploring the microenvironments within and around catalyst particles. The authors examined [8] the prospects of tailoring the catalyst microenvironment while reviewing the scientific advances made in the sulfuric acid fi ee toluene nitration employing solid acid catalysis. Haouas et al., [9] carried out toluene nitration with nitric acid and acetic anhydride employing H Beta Zeolite catalyst. They attributed the enhancement of para-selectivity in the mononitro toluenes to the transformation of lattice aluminum framework of the catalyst from a tetrahedral (TH)... 

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