Super high activity catalyst

LIPP-SHAC [Liquid polymerization of propylene with super high activity catalyst] A process for making polypropylene. Developed by the Shell Chemical Company and used at Pemis, The Netherlands Carrington, England and Geelong, Australia. 

COMPOSITEMATERIALS - SURVEY] (Vol 7) SITAC. See Super high activity catalyst. 

A new class of super highly active catalysts based on an MgCl2 support have been developed since the late 1970s. These catalysts are characterised by the appearance of surface-active species of practically one type. Their productivities are up to 2000 kg of polypropylene (with an isotactic index of 95-98 %) per gram Ti/h. In addition, lower Al/Ti ratios, i.e. ratios of the trialkylaluminium activator to titanium species, are required, and the usual reciprocal correlation between polypropylene isotactic index and yield is virtually absent [28,38],... 

Ethylene, hydrogen, co-monomer and a super-high activity catalyst are fed into the reactors (1). Polymerization reaction occurs under a slurry state. The automatic polymer property control system plays a very effective role in product-quality control. Slurry from the reactors is pumped to the separation system (2). The wetcake is dried into powder in the dryer system (3). As much as 90% of the solvent is separated from the slurry and is directly recycled to the reactors without any treatment. The dry powder is pelletized in the pelletizing system (4) along with required stabilizers. 

Chadwick, J. G. Effects of Electron Donors in Super High Activity Catalysts for Polypropylene. In Ziegler Catalysts-, Fink, G., Miilhaupt, R., Brintzinger, H.-H., Eds. Springer Berlin, 1995 p 427. 

Solid super bases, prepared by successive treatment of y-alumina with alkali metal hydroxide and alkali metal, are highly active catalysts for reactions involving reactive carbanions, and have been commercialised by Sumitomo (Suzukamo et al, 1997). For example, t.vobutylbenzene, the. starting material for ibuprofen (see earlier) is produced by side-chain alkylation of toluene with propylene over a K/KOH/AI2O3 catalyst (Eqn. (14)). 

Description Catalyst in mineral-oil-slurry is metered into the reactor together with co-catalyst and modifier. The proprietary supported catalyst developed by BP has control morphology, super-high activity and very high sterospecifity. The resulting PP product is characterized by narrow particle size distribution, good powder flowability, minimum catalyst residues, noncorrosiveness, excellent color and low odor. 

Recently, we reported that an Fe supported zeolite (FeHY-1) shows high activity for acidic reactions such as toluene disproportionation and resid hydrocracking in the presence of H2S [1,2]. Investigations using electron spin resonance (ESR), Fourier transform infrared spectroscopy (FT-IR), MiJssbauer and transmission electron microscopy (TEM) revealed that superfine ferric oxide cluster interacts with the zeolite framework in the super-cage of Y-type zeolites [3,4]. Furthermore, we reported change in physicochemical properties and catalytic activities for toluene disproportionation during the sample preparation period[5]. It was revealed that the activation of the catalyst was closely related with interaction between the iron cluster and the zeolite framework. In this work, we will report the effect of preparation conditions on the physicochemical properties and activity for toluene disproportionation in the presence of 82. ... 

The tungstophosphoric acid shows high activity, close to H2SO4 used as a benchmark. Regrettably, this acid is soluble in water and hence not usable as a solid catalyst. However, the corresponding cesium salt (Cs2.5) is also super acidic and its mesoporous structure has no limitations on the diffusion of the reactants. Cs2.5 exhibits low activity per weight, hence it is not suitable for industrial applications. 

After an iPP particle reached the FBR, co-polymerization of ethylene-propylene starts preferrably inside the porous PP matrix. Depending on the individual residence time, the particle will be filled with a certain amount of ethylene-propylene rubber, EPR, that improves the impact properties of the HIPP. It is important to keep the sticky EPR inside the preformed iPP matrix to avoid particle agglomeration that could lead to wall sheeting and termination of the reactor operation. Ideally a "two phase" structure, see Fig.5.4-3, is produced. Finally, a "super-high impact" PP results that contains up to 70% EPR. How much EPR is formed per particle depends on three factors catalyst activity in the FBR, individual particle porosity, and individual particle residence time in the FBR. All particle properties are therefore influenced by the residence time distribution, and finally, a mix of particles with different relative amounts of EPR is produced - a so called "chemical distribution" see, for example, [6]. 

The best combination of chiral ligands and activators can easily be found out in an efficient way by super high throughput screening (SHTS) employing CO-HPLC with achiral stationary phase for affording the most enantioselective activated catalyst to give excellent yields and enantioselectivities. 

Cationic oxazaborinane 59 (Figure 3.10) is a chiral super-Lewis-acidic catalyst recently described by Corey and coworkers [61]. The catalyst is in equilibrium with 59a and the oxazaborinane system 59 5 59a is unstable and undergoes gradual decomposition at temperatures above -60 °C. A more active catalyst system is the tetraarylborate salt 59+B[C6H3 - 3,5 - (CF3)2]4 which allows the cycloadditions of cyclopentadiene (18) and a./i-unsaturated aldehydes to occur with a high level of stereoselectivity and enantioselectivity (Equations 3.16 and 3.17). 

Dialkylaminopyridines as highly active acylation catalysts , Hofle, G., Steglich, W. and Vorbruggen, H.,Angew. Chem., Int. Ed. Engl, 1979,17, 569 4-Dialkylaminopyridines super acylation and alkylation catalysts , Scriven, E. F. V., Chem. Soc. Rev., 1983, 12, 129. 

The five basic, indispensable requirements for a super-active catalyst are as follows High surface area. 

Keywords High density polyethylene Process control Process design Process modelling Product portfolio Super-active catalysts Ziegler slurry polymerization... 

In conclusion, super-active catalysts used in technical processes have a very high activity but do not overheat at the start-up of polymerization and remain at this high activity level over a long period of time in the range of the average residence time of around 1-2.5 h depending on process design (see Sect. 4). Only with those catalysts can the modem process be operated effectively. 

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