Basic chemicals, additives

The basic chemical premise involved in making synthetic natural gas from heavier feedstocks is the addition of hydrogen to the oil ... 

The synthesis of dehydro-hnalool (28) rehes on the basic chemicals acetone and acetjiene. Addition of a metal acetyUde to acetone yields methylbutynol (33). Semihydrogenation affords the alkene (34) which is reacted with /-propenylmethyl ether. A Cope rearrangement of the adduct yields methyUieptenone (35). Addition of a second mole of metal acetyUde to dehydro-linalool (28) is followed by a second Cope rearrangement to yield... 

In the pulp and paper industry, anionic and cationic acrylamide polymers are used as chemical additives or processing aids. The positive effect is achieved due to a fuller retention of the filler (basically kaoline) in the paper pulp, so that the structure of the paper sheet surface layer improves. Copolymers of acrylamide with vi-nylamine not only attach better qualities to the surface layer of.paper, they also add to the tensile properties of paper in the wet state. Paper reinforcement with anionic polymers is due to the formation of complexes between the polymer additive and ions of Cr and Cu incorporated in the paper pulp. The direct effect of acrylamide polymers on strength increases and improved surface properties of paper sheets is accompanied by a fuller extraction of metallic ions (iron and cobalt, in addition to those mentioned above), which improves effluent water quality. 

There exist a considerable number of compounds containing labile chlorine which bring about sulfur-less vulcanization at levels of approximately 3 phr [64] as basic chemicals such as lead oxides and amines are needed. Additionally, it may be assumed that diene mbbers are cross-linked by such systems through the formation of C-C links this would mean, initially, hydrogen chloride is split off and later neutralized by the base. Examples of chemicals that act in the manner are listed below ... 

While analyzing the outcome of RISKCYCLE project [1] one of the main points noticed is that selected hazardous pollutants (chemical additives) that are contained in consumer and industrial products, are ultimately circulated globally due to the products waste/recycling path. These global pollutant cycles are likely to pose risks to humans and the environment, but for a final evaluation of the impacts, many basic data are lacking. 

Several of these steps are shown in schematic fashion in Figure 6.3. Of course, if the catalyst is nonporous, steps 2 and 6 are absent. Steps 1, 2, 6, and 7 are obviously physical processes, while steps 3 to 5 are basically chemical in character. The rates of the various steps depend on a number of factors in addition to the concentration profiles of the reactant and product species. 

The Chemicals Group markets over 7000 products. In addition to basic chemicals such as industrial salts, household salt, chlorine and methylamines, Akzo Nobel produces a wide range of special chemical products. 

Despite of 150-year s history of vulcanization process, it is impossible to consider that fundamental and applied researches in direction of vulcanization systems perfection are completed. For today one of the ways of rubbers properties improvement is the synthesis and application of the new chemicals-additives, including, vulcanization active, that is connected, first of all, with reduction of global stocks of zinc ores as basic raw material for reception of traditional activator - zinc oxide. Besides, modem increase of industrial potential and the accumulation of big quantity wastes derivate the problems of ecological character, which require the emergency decision. Therefore creation of resourcesaving technologies of the new compounds reception from products of secondary raw material processing has paramount importance. 

Studies on morphology and conclusions about observed levels of proton conductivity have also been carried out on PEMs other than Nafion and sulfonated poly(ether ketone). These include studies in which phenomenological examinations of relationships between conductivity and observed microstructure were carried out upon polymer systems where acid content was varied but the basic chemical structure was kept constant. In addition, other systems allowed... 

In addition, many mineral species, such as the chain silicates, contain identical basic chemical units, and hence exhibit very similar crystal structures but have different chemical compositions. These minerals may be members of a mineral series if the chemistry varies predictably. The variations, known as atomic substitution, are based on Pauling s rules. 

The basic structure of all steroid hormones is similar (see Chapter 60, Fig. 60.4). The addition of a hydrogen atom at position 5 and an angular methyl group at positions 18 and 19 establishes the basic chemical framework for androgenic activity. 

Having produced many different carbon skeletons via the first phase of the isoprenoid/terpenoid pathway, the second phase of diversity generation occurs in all organisms when a number of versatile enzymes carry out a series of chemical additions, rearrangements and deletions by acting on different carbons in the basic skeleton. The... 

The questions of interest to an engineer in this case are How do the initial concentration, the particle size, and the nature of the interparticle potential affect the structure of the dispersion, the structure of the final specimen, and the processing time How long does the process take What kinds of chemical additives are suitable The permeability and the capillary suction in the mold determine the rate of production of the specimens. How does one adjust the two to optimize production These questions require a basic understanding of colloid and surface science and phenomena. 

In the following the basic chemical and physical properties of free flavin will be described in some detail, because the knowledge of these properties is the key for a detailed understanding of the function of flavoproteins. In addition, some general and common properties of the classes of flavoproteins will be presented and discussed in relation to some new concepts. It will however not be possible to cover the whole literature. For the reader interested in more details, the recent review papers by Massey and Hemmerich Bruice , Walsh Simondson and Tollin , and Hemmerich (and references therein) should be consulted. An overview of the pertinent research on flavins and flavoproteins is easily accessible by the proceedings of the international symposia... 

Most artificial gases, such as producer gas. coal gas. water gas. manufactured gas. and town gas contain a high content of methane. In addition to its use as a basic chemical and fuel, methane is of notable interest because of its role as the anchor compound of the alkanes (paraffin or aliphatic hydrocarbons). All of these compounds may be considered derivatives of methane. 

In basic chemicals, nitrile hydratase and nitrilases have been most successful. Acrylamide from acrylonitrile is now a 30 000 tpy process. In a product tree starting from the addition of HCN to butadiene, nicotinamide (from 3-cyanopyridine, for animal feed), 5-cyanovaleramide (from adiponitrile, for herbicide precursor), and 4-cyanopentanoic acid (from 2-methylglutaronitrile, for l,5-dimethyl-2-piperidone solvent) have been developed. Both the enantioselective addition of HCN to aldehydes with oxynitrilase and the dihydroxylation of substituted benzenes with toluene (or naphthalene) dioxygenase, which are far superior to chemical routes, open up pathways to amino and hydroxy acids, amino alcohols, and diamines in the first case and alkaloids, prostaglandins, and carbohydrate derivatives in the second case. 

Steroid hormones bear a remarkable structural similarity to one another (see Fig. 29-1). The precursor for steroid biosynthesis is cholesterol. Consequently, all of the steroid hormones share the same basic chemical configuration as their parent compound. This fact has several important physiologic and pharmacologic implications. First, even relatively minor changes in the side chains of the parent compound create steroids with dramatically different physiologic effects. For instance, the addition of only one hydrogen atom in the sex steroid pathway changes testosterone (the primary male hormone) to estradiol... 

Chemical products can be roughly segmented into basic chemicals, polymers, specialty and performance products, industrial gases, and agrochemicals. However, for practical purposes they are usually classified as commodities and specialties , the latter having higher value added and distinctive key success factors that allow for some additional differentiation between competing products. Albeit this distinction is commonplace in the industry, it should be kept in mind that chemical commodities are not nearly as commoditized as true commodities such... 

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