Aromatics, prices

Figure 7 shows the effect on ethylene production cost from naphtha cracking with BTX aromatics value increases as a parameter. (The basis we have used for determining the effect of aromatics price increases is given in Table XII). Figure 7 indicates that a 5 /gal increase in BTX... 

Aliphatic Isocyanates. Aflphatic diisocyanates have traditionally commanded a premium price because the aflphatic amine precursors ate mote expensive than aromatic diamines. They ate most commonly used in appHcafions which support the added cost or where the long-term performance of aromatic isocyanates is unacceptable. Monofuncfional aflphatic isocyanates, such as methyl and -butyl isocyanate, ate used as intermediates in the production of carbamate-based and urea-based insecticides and fungicides (see Fungicides, agricultural Insectcontroltechnology). 

Uses. Pyromellitic dianhydride imparts heat stabUity in applications where it is used. Its relatively high price limits its use to these applications. The principal commercial use is as a raw material for polyimide resins (see POLYIMIDES). These polypyromellitimides are condensation polymers of the dianhydride and aromatic diamines such as 4, -oxydianifine ... 

A typical catalytic hydrodealkylation scheme is shown ia Figure 3 (49). The most common feedstock is toluene, but xylenes can also be used. Recent studies have demonstrated that and heavier monoaromatics produce benzene ia a conventional hydrodealkylation unit ia yields comparable to that of toluene (51). The use of feeds containing up to 100% of C —aromatics iacreases the flexibiUty of the hydrodealkylation procedure which is sensitive to the price differential of benzene and toluene. When toluene is ia demand, benzene suppHes can be maintained from dealkylation of heavy feedstocks. 

U.S. petroleum benzene prices since 1974 are Hsted in Table 6 (64). Until 1978, benzene prices were relatively stable and through 1985 they increased considerably, peaking in 1981 because of the increased demand for aromatics in the gasoline pool. At that time, there was also a large surplus of low priced imported benzene and a softening of the ethylbenzene—styrene market. The decline of cmde oil prices in 1986 caused a dramatic drop in domestic benzene prices. In 1987, U.S. benzene production increased 13.9% over 1986, and this rise was largely ascribed to a favorable export market for benzene derivatives... 

Although it is somewhat of an oversimplification, the polysulphones are best considered as a group of materials similar to the aromatic polycarbonates but which are able to withstand more rigorous conditions of use. Because of their higher price they are only considered when polycarbonates or other cheaper polymers are unsuitable. 

Diphenol/thiophenol is one of the most important polymer precursors for synthesis of poly(aryl ethers) or poly-(aryl sulfides) in displacement polymerizations. Commonly used bisphenols are 4,4 -isopropylidene diphenol or bisphenol-A (BPA) due to their low price and easy availability. Other commercial bisphenols have also been reported [7,24,25]. Recently, synthesis of poly(aryl ethers) by the reaction of new bisphenol monomers with activated aromatic dihalides has been reported. The structures of the polymer precursors are described in Table 2. Poly(aryl ether phenylquinoxalines) have been synthesized by Connell et al. [26], by the reaction of bisphenols containing a preformed quinoxaline ring with... 

DO is the lowest priced product and the goal is to reduce its yield. The DO s yield largely depends on the quality of the feedstock and the conversion level. Naphthenic and aromatic feedstocks tend to yield more bottoms than paraffinic feedstocks. If the conversion is m the low- to mid-70 s, increasing catalyst-to-oil ratio or using a catalyst with an active matrix can reduce slurry yield. Raising conversion reduces bottoms yield. If the conversion is in the 80 s, little more can be done to reduce bottoms yields. 

Table 4 shows that the substrates usually involved in the reaction with polydichlorophosphazene belong to the categories of aliphatic or aromatic compounds containing in their own chemical structure free -OH and/or -NH2 functionalities, which can be easily found on the market in great abundance and at cheap prices. 

Price i was the first to suggest that the factor of specificity in monomer addition is owing to electrostatic interaction of net charges on the monomer double bond and on the radical arising from polarization by the substituent. Alfrey and Price proposed that the rate constant be written, in analogy with Hammett s equation for the effects of nuclear substituents on the reactivity of aromatic compounds, as follows ... 

The behavior of the different amines depends on at least four factors basicity, nucleophilicity, steric hindrance and solvation. In the literature (16), 126 aliphatic and aromatic amines have been classified by a statistical analysis of the data for the following parameters molar mass (mm), refractive index (nD), density (d), boiling point (bp), molar volume, and pKa. On such a premise, a Cartesian co-ordinate graph places the amines in four quadrants (16). In our preliminary tests, amines representative of each quadrant have been investigated, and chosen by consideration of their toxicity, commercial availability and price (Table 1). 

Transmetallation of aiyl halide (VIII) with n-butyl lithium and treating it with readily available and inexpensive 3-ethoxycyclohexen-l-one followed by acid work-up would provide enone (XI) (Scheme 8). Enone (XI) can be then aromatized to phenol (X) or any other biaryl alkyl ether. By using this protocol, 3-ethoxycyclohexen-l-one is a synthon for 3-hydroxyphenyl boronic acid. The bulk price of 3-ethoxycyclohexen-l-one is 85/kg compared to 3500 for the boronic acid, thereby significantly reducing the cost to prepare biaryl (X). 

Stoker, P.W., M.R. Plasterer, R.L. McDowell, R. Campbell, S. Fields, R. Price, C. Muehle, W.R. West, G.M. Both, J.R. Larsen, and M.L. Lee. 1984. Effects of coal-derived tars on selected aquatic and mammalian organisms. Pages 1239-1257 in M. Cooke and A.J. Dennis (eds.). Polynuclear Aromatic Hydrocarbons Mechanisms, Methods and Metabolism. Battelle Press, Columbus, OH. 

Extrusion reactions, aromatic system formation by, 21 148 Extrusion rheometers, 21 730-731 Exudate gums, 13 61, 63t Exudation, from TNT, 10 734 Ex-works prices, 15 37 Exxal 6... 

The phthalic anhydride based resins were the first developed useful unsaturated resins. Using phthalic anhydride offers resin producers the flexibility to substitute, mole-for-mole , maleic anhydride out of the formulation and therefore reduce the active double-bond sites. Consequently, the product becomes less brittle. Furthermore, aromatic acid components in the polymer backbone provided much better strength for the cured products. Phthalic anhydride is not a costly material and historically it is similarly priced to maleic anhydride. By... 

Ether-linked bisphthalonitriles were synthesized by Mr. T. R. Price of the Naval Research Lab. A number of monomers containing various aliphatic and aromatic "linking groups" between the phthalonitrile functions are available three representative aromatic monomers were selected for this study... 

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