Promoters Accelerators

Forderer, m. promoter accelerator conveyer. Ffirder-gut, n. goods to be conveyed or forwarded output, -hohe, /. delivery head, pressure head, -kohle, /. rough coal, coal directly from the mine, run-of-mine. forderlich, a. serviceable speedy. Forder-menge, /. output, -mittel, n. transportation means conveyer, fordem, v.t. demand, ask, require summon challenge. 

Innes, W. B., Catalyst Carriers, Promoters, Accelerators, Poisons, and Inhibitors, Chapter 6 in Catalysis, Volume I, edited by P. H. Emmett, Reinhold, New York, 1954. 

While filgrastim has proved a useful adjuvant to chemotherapy for many cancers, its administration in cases of myeloid leukaemia would give cause for concern, as these cells express receptors for G-CSF. In such cases, G-CSF could potentially promote accelerated growth of these malignant cells. 

The ability of such factors to promote accelerated cellular growth and division has predictably attracted the attention of the pharmaceutical industry. The clinical potential of a range of such factors, e.g. to accelerate the wound-healing process, is currently being assessed in various clinical trials (Table 7.2). 

The addition of increasing amounts of iodine promoters accelerates the hydrocarbonylation of methanol, but at the same time detioriates the hydrogenation ability of the cobalt catalysis. To obtain a high ethanol selectivity under these conditions, catalysts active for hydrogenation in the presence of iodine have to be added. Ruthenium compounds have been proved to be most suitable, as was mentioned earlier. Althou no detailed studies on the ruthenium intermediates involved are available, it is well known that aliphatic aldehydes... 

This chapter is intended to focus on catalysis in both thermal and photoinduced electron transfer reactions between electron donors and acceptors by investigating the effects of an appropriate substance that can reduce the activation barrier of electron transfer reactions. It is commonly believed that a catalyst affects the rate of reaction but not the point of equilibrium of the reaction. Thus, a substance is said to act as a catalyst in a reaction when it appears in the rate equation but not in the stoichiometric equation. However, autocatalysis involves a product acting as a catalyst. In this chapter, a catalyst is simply defined as a substance which affects the rate of reaction. This is an unambiguous classification, albeit not universally accepted, including a variety of terms such as catalyzed, sensitized, promoted, accelerated, enhanced, stimulated, induced, and assisted. Both thermal and photochemical redox reactions which would otherwise be unlikely to occur are made possible to proceed efficiently by the catalysis in the electron transfer steps. First, factors that accelerate rates of electron transfer are summarized and then each mechanistic viability is described by showing a number of examples of both thermal and photochemical reactions that involve catalyzed electron transfer processes as the rate-determining steps. Catalytic reactions which involve uncatalyzed electron transfer steps are described in other chapters in this section [66-68]. 

Which types of catalytic reactions can be promoted (accelerated) by such a pronounced decrease in catalyst work function They are called electrophilic, and we discuss them in the next section, together with their counterpart, electrophobic reactions, which are promoted by increasing catalyst work function. 

The model based on metal-hydroxide ions ([MOH]+) was further developed by Grande and Talbot [71]. Sasaki and Talbot [72] demonstrated the extendibility of this model to the electrodeposition of Co—Fe and Ni—Co alloys. They found that there is a slight inhibition of the more positive metal deposition and a promotion (acceleration) of the less positive metal deposition for all binary iron-group alloys. 

One widely known example of such ineffective attempts is the direct oxidation of methane-to-methanol (DOMM) (see Arutyunov and Krylov, 1998 and literature cited therein). Whereas at atmospheric or somewhat higher pressures the introduction of catalysts (or homogeneous promoters) accelerates the process and increases product (mainly formaldehyde) yield to some extent, at increasing pressures their efficiency sharply drops. As a result, the methanol yield cannot be increased by any means above the level attainable in high-pressure homogeneous oxidation. 

In the steam reforming of naphtha, potassium promoters accelerate the reaction of carbon with steam. However, this leads to formation of KOH, which sublimes. In this case, potassium aluminosilicate was successfully used as promoter. In the presence of steam and CO2 it decomposes into K2CO3 and KOH to an extent that is just sufficient to remove the coke that is formed. This prolonged catalyst lifetimes to 4-5 years [T35]. 

MW-promoted acceleration of such dehydration reactions using montmorillonite K 10 clay 40) or Envirocat reagent 41), EPZG (Scheme 7, 8) has been demonstrated in the preparation of imines and enamines. Microwaves at 2450 MHz... 

The policy of adopting these test methods for promoting accelerated wear tests which are representative of performance under normal operating conditions has been confirmed by prolonged service running of the most promising combinations. The results obtained from these tests indicate a second phase of steady very low wear rate after the initial heavier wear rate. However, the individuad combinations remain in the same order of merit. 

UPRs are composed not only of UPs and a crosslinking monomer, usually styrene they contain, moreover, initiators (hardeners), curing promoters (accelerators) and polymerization inhibitors, hi the systems with benzoyl peroxide as the initiator, tertiary aromatic amines, e.g. N,N-dimethylaniline or Ar,M-dimethyl-p-toluidine, are applied as the promoters. Some amino-glycols were built into the UP molecules, thus increasing the reactivity [170]. The best results were achieved when using 3,6-diaza-3,6-diphenyloctane-l,8-diol (Scheme 25) ... 

Wittenberg, N.J., L. Zheng, N. Winograd, and A.G. Ewing. 2008. Short-chain alcohols promote accelerated membrane distention in a dynamic hposome model of exocytosis. Langmuir 24 2637-2642. 

Recently, a new MF resin, tri(methoxymethyl)trimethylmelamine (TMMTMM), has been developed which has been found to be very useful in HS coatings. This has been shown to give faster curing and a unique combination of properties as compared to HMM, with a response to weak acid catalysis at a lower cure temperature (125 °C). The major drawback with this resin is that the cured films undergo decomposition under 60 °C Cleveland humidity conditions. Film decomposition has been assumed to be due to the higher basicity of TMMTMM, which promotes accelerated acid-catalyzed hydrolysis of the crosslinked sites. 

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