Chemical demand

Synthetic Fiber and Plastics Industries. In the synthetic fibers and plastics industries, the substrate itself serves as the solvent, and the whitener is not appHed from solutions as in textiles. Table 6 Hsts the types of FWAs used in the synthetic fibers and plastic industries. In the case of synthetic fibers, such as polyamide and polyester produced by the melt-spinning process, FWAs can be added at the start or during the course of polymerization or polycondensation. However, FWAs can also be powdered onto the polymer chips prior to spinning. The above types of appHcation place severe thermal and chemical demands on FWAs. They must not interfere with the polymerization reaction and must remain stable under spinning conditions. 

As Figure 14 also shows, the only acetylene derivatives to sustain growth during this period were the so-called acetylenic chemicals. These include 1,4-butanediol, vinyl ethers, A/-vinyl-2-pyrroHdinone, and butanediol. Of these, 1,4-butanediol, a principal feed for tetrahydrofuran, accounts for over 90% of the acetylenic chemicals demand (38). 

The current chemical demand for propylene is a little over one half that for ethylene. This is somewhat surprising because the added complexity of the propylene molecule (due to presence of a methyl group) should permit a wider spectrum of end products and markets. However, such a difference can lead to the production of undesirable by-products, and it frequently does. This may explain the relatively limited use of propylene in comparison to ethylene. Nevertheless, many important chemicals are produced from propylene. 

In the production of anionic surfactants, the analytical procedures to be adopted for quality control and/or assessment are of particular importance. Their reliability as well as their time and chemical demand is a fundamental topic for the economy and success of the surfactant production cycle. To this end the most important analyses to be done on the various types of anionic surfactants are outlined in Tables 15-19. Mention must be made of potentiometric titration of the sulfonic acid (whatever the processed feedstock), which allows one to obtain reliable results over a very short time. 

Safe handling of chemicals demands a combination of hardware and software such as operating procedures, staff selection and training. Systems of work will generally include ... 

Chemical customers vary significantly with regard to their expectations of what constitutes acceptable service, so it is necessary to consider the manner in which chemicals are used in a particular system. For example, high chemical demand that is... 

To summarize, an increasingly constricted industry is an engine for the expansion of chemical commodity markets and the invention of new arenas for the consumption of chemicals. It is in part the supply of pesticides, herbicides, and fertilizers that sets the conditions for chemical demand. Internalizing the costs associated with chemical risks, especially under these constrictive economic conditions, is essentially unthinkable. As such, the risks and hazards associated with the industry are largely shunted downwards along the commodity chain to other players, including applicator service providers. 

More toluene is formed than is needed in the catalytic reforming of naphtha. Benzene is always in tight supply. Table 8.7 shows the catalytic reformate production percentages of benzene, toluene, and xylene vs. the U.S. chemical demand. When the price is right it is economical to hydrodealkylate (add hydrogen, lose the methyl) toluene to benzene. This is best done on pure toluene, where the yield can be as high as 98.5%. The reaction can be promoted thermally or catalytically. As much as 30-50% of all benzene is made this way. 

Solids contact lowest chemical demand and higher effluent quality... 

Because certain herbicides can predispose plants to disease (ISl) and because efficient Integrated weed control (biological and chemical) demands that there be little or no adverse Interactions when these two systems are used simultaneously, further research In this area Is necessary. Indeed It would be useful, for example. If a herbicide and pathogen Interaction was synergistic against weeds. 

Tempered steel is used for the construction of all these pressure reactors, alloyed with chromium and molybdenum to make them resistant to hydrogen under pressure, so that no decarburization, embrittlement and grain boundary splitting occurs. These pressure reactors are more and more being constructed out of several layers. In this way the total reactor wall is built up of a multitude of individual layers, which are wound round a central tube. The advantage of such a multiple layer construction, as against pressure chambers with a plate-girder construction, is that the central tube is subject to chemical demands and the adjacent layers... 

The products in the foregoing tabulation represent only the chemical demand for propylene. Much of the propylene generated in refineries is consumed for gasoline components (polygasoline in an oligomers unit) or is used as fuel in the refinery. The reason is that the combined production of propylene from olefins plants and refineries far exceeds the chemical demand. 

Rapid economic and chemical demands as well as growth in developing economies... 

As is the case for most of the higher technology industries, chemical demand and production are both dominated by the NAFTA, EU and Asia/Pacific regions. These three regions together accounted for 84% of worldwide production and 81% of sales in 1999, and in no other region does the per capita consumption of chemicals come close to the world average (see Table 5.1). 

In this chapter we will examine the catalytic strategies that hydrolases employ to meet these chemical demands. 

Attention to the propylene shortage had crystallized with the publication of a major study by Stobaugh (56) in 1967, in which he analyzed thoroughly the sources and markets for propylene. He suggested that by 1970 over-all propylene production from both refining and chemical sources would probably not exceed 19 billion lbs, and chemical demand would have increased to 7.5 billion lbs at a value of 2.5 cents/lb. Stobaugh lists both U.S. propylene producers and their plant capacities as well as propylene consumers. 

Ockerbloom and Mitchell (II, 43) pointed out that the shortage predicted by 1970 could be aggravated by factors such as growth of propylene chemical demand even beyond forecast levels and by legislation against lead alkyls. 

C EN (12) has listed propylene markets which show that by 1968 Stobaugh s 7 billion lb prediction had been met and that price had risen past 2.5 cents to 3.0 cents/lb for chemical grade propylene (90-95% purity). Table II shows the use breakdown for propylene and also a prediction of 11 billion lbs chemical demand by 1973. 

It was pointed out above that nitrite is usually present only in traces in arable soils. We have always explained this by saying that nitrate-forming bacteria remove it as fast as formed. In the light of the newer knowledge we may need to emphasize that there is both a biological and a chemical demand for each bit of nitrite as the Nitrosomonas bacteria produce it. 

The chromatographically and chemically demanding pyridoxyl group which anyhow did not display the required tautomerizing activity could consequently be replaced by the cheaper benzyl residue (see Scheme 21) (33,38). Thus, reaction of diketones like 75 with benzylamine and subsequent reduction of the intermediate isoquinolinium salt 86 provided a very efficient one-pot synthesis of the required tetrahydroisoquinolines 92 and 93, which were moreover already ben-zylated for further syntheses. 

---