Industrial catalyst formulations

Silver alone on a support does not give rise to a good catalyst (150). However, addition of minor amounts of promoter enhance the activity and the selectivity of the catalyst, and improve its long-term stabiHty. Excess addition lowers the catalyst performance (151,152). Promoter formulations have been studied extensively in the chemical industry. The most commonly used promoters are alkaline-earth metals, such as calcium or barium, and alkaH metals such as cesium, mbidium, or potassium (153). Using these metals in conjunction with various counter anions, selectivities as high as 82—87% were reported. Precise information on commercial catalyst promoter formulations is proprietary (154—156). 

The key to good reactor simulation is undoubtedly a knowledge of the reaction kinetics. The kinetics of the catalytic oxidation of benzene to maleic anhydride has been studied for different catalysts and conditions by many workers (8-13) however only Quach et al ( ) examined a catalyst, FX203, of a type simi-liar to that employed by Kizer et al (FB203-S). Both catalysts are fabricated by Halcon Catalyst Industries, but are of different formulation. 

Campbell, J.S. Influences of catalyst formulation and poisoning on the activity and die-off of low temperature shift catalysts. Industrial and Engineering Chemistry Process Design and Development, 1977, 9, 588. 

Initially it was intended to use the alumina as smelter feed. However, as the unique character of this alumina became clear, it was introduced to other markets, in particular the catalyst market. For the catalyst industry this was an unknown type of material and it was difficult to convince catalyst makers to use Ziegler-alumina in their formulation. Finally, the breakthrough came when catalyst manufacturers recognized the advantages of the high purity and the specific physical properties of alkoxide derived aluminas. 

Different reactive routes were adopted to generate in situ the block copolymers. A criterion of classification of the different methods can be tentatively made by considering the different compatibilizer precursors added to polymer blends a catalyst, a polymer bearing reactive groups, or a reactive additive. In the following, it is necessary to take into account that, often in industrial formulations, more than one compatibilizer precursor might be used. 

It is common practice in the siHcone mbber industry to prepare specific or custom mixtures of polymer, fillers, and cure catalysts for particular appHcations. The number of potential combinations is enormous. In general, the mixture is selected to achieve some special operating or processing requirement, and the formulations are classified accordingly. Table 6 Hsts some of the commercially important types. 

Curing Catalysts for A Methylol Agents. Many acid-type catalysts have been used in finishing formulations to produce a durable press finish. Catalyst selection must take into consideration not only achievement of the desked chemical reaction, but also such secondary effects as influence on dyes, effluent standards, formaldehyde release, discoloration of fabric, chlorine retention, and formation of odors. In much of the industry, the chemical suppher specifies a catalyst for the agent so the exact content of the catalyst may not be known by the finisher. 

Type AD-G is used in an entirely different sort of formulation. The polymer is designed for graft polymerisation with methyl methacrylate. Typically, equal amounts of AD-G and methyl methacrylate are dissolved together in toluene, and the reaction driven to completion with a free-radical catalyst, such as bensoyl peroxide. The graft polymer is usually mixed with an isocyanate just prior to use. It is not normally compounded with resin. The resulting adhesive has very good adhesion to plasticised vinyl, EVA sponge, thermoplastic mbber, and other difficult to bond substrates, and is of particular importance to the shoe industry (42,43). 

A good methanation catalyst is one which is physically strong, is reducible at 300°C (570°F) and has high activity. In order to provide a long life, it must retain these properties in use. Lives of 3-5 years are commonly obtained from charges of Imperial Chemical Industries, Ltd. (ICI) catalyst 11-3, depending on the temperature of operation and the presence of poisons in the synthesis gas, factors which are discussed below. These properties can be obtained by careful attention to the formulation and manufacture of the catalyst. 

The attention given to the causes and control of catalyst die-off in industry is well illustrated by the behavior of different formulations of Cu-ZnO-AhOs catalysts for the low temperature water gas shift reaction. 

Hydroformylation is an important industrial process carried out using rhodium phosphine or cobalt carbonyl catalysts. The major industrial process using the rhodium catalyst is hydroformylation of propene with synthesis gas (potentially obtainable from a renewable resource, see Chapter 6). The product, butyraldehyde, is formed as a mixture of n- and iso- isomers the n-isomer is the most desired product, being used for conversion to butanol via hydrogenation) and 2-ethylhexanol via aldol condensation and hydrogenation). Butanol is a valuable solvent in many surface coating formulations whilst 2-ethylhexanol is widely used in the production of phthalate plasticizers. 

Suppose that our tests in the laboratory have yielded a formulation with an excellent activity in terms of turnover per active site for a certain reaction, and a fabulous selectivity towards the desired product. Will this substance be a successful catalyst in an industrial application Not necessarily. It will have to be developed into a material with the following properties. 

Experimental Materials. All the data to be presented for these illustrations was obtained from a series of polyurethane foam samples. It is not relevant for this presentation to go into too much detail regarding the exact nature of the samples. It is merely sufficient to state they were from six different formulations, prepared and physically tested for us at an industrial laboratory. After which, our laboratory compiled extensive morphological datu on these materials. The major variable in the composition of this series of foam saaqples is the aaK>unt of water added to the stoichiometric mixture. The reaction of the isocyanate with water is critical in determining the final physical properties of the bulk sample) properties that correlate with the characteristic cellular morphology. The concentration of the tin catalyst was an additional variable in the formulation, the effect of which was to influence the polymerization reaction rate. Representative data from portions of this study will illustrate our experiences of incorporating a computer with the operation of the optical microscope. 

Very seldom does an industrial catalyst consist of a single chemical compound or metallic element. Most often a catalyst formulation consists of a multitude of components, each of which performs an essential task in the creation of a commercially viable catalyst. Figure 6.7,... 

We report here about the investigation of the low temperature watergas shift reaction on an industrial catalyst (GIRDLER G 66-B and E with copper and zinc oxides as main components) under transient conditions by means of wavefront analysis. After a qualitative analysis to obtain information about the relevant mechanistic scheme the main effort has been concentrated on the dependence of the microkinetics on different oxidation states of the catalyst. The watergas shift reaction in its overall formulation... 

---