High boiling aromatics

The main product, benzene, is represented by solute (B), and the high boiling aromatics are represented by solute (C) (toluene and xylenes). The analysis of the products they obtained are shown in Figure 12. The material stripped form the top section (section (1)) is seen to contain the alkanes, alkenes and naphthenes and very little benzene. The product stripped from the center section appears to be virtually pure benzene. The product from section (3) contained toluene, the xylenes and thiophen which elutes close to benzene. The thiophen, however, was only eliminated at the expense of some loss of benzene to the lower stripping section. Although the system works well it proved experimentally difficult to set up and maintain under constant operating conditions. The problems arose largely from the need to adjust the pressures that must prevent cross-flow. The system as described would be virtually impossible to operate with a liquid mobile phase. 

A schematic diagram of the liquid solvent extraction process is illustrated in Figure 1. Where the production of liquid hydrocarbons is the main objective an hydrogenated donor process solvent is used, whereas in the production of needle coke this is not necessary and a coal derived high boiling aromatic solvent may be used (e.g. anthracene oil). An essential economic requirement of the process is that a high extraction yield of the coal is obtained and this will depend upon the coal used and the digestion conditions. 

The reactants are phthalic anhydride, urea and copper(n) chloride, which are heated in a high-boiling aromatic solvent such as 1,2,4-trichlorobenzene, nitrobenzene or m-dinitrobenzene in the presence of a catalyst, usually ammonium molybdate. The solvent also acts as a heat-transfer medium. On heating to 120 °C an exothermic reaction begins and this temperature is maintained for about an hour. The temperature is then raised to 160-180 °C and kept constant for 6-12 hours. During this time ammonia and carbon dioxide are evolved, together with some solvent the reaction is complete when ammonia evolution ceases. The remaining solvent is then removed by either steam or vacuum distillation. The yield is 90-95%. For many years the solvent process was in almost exclusive use. 

The reduction of polymers can be carried out by using a diimide, generated in situ. The precursor for diimide can be p-toluenesulfonyl hydrazide (TSH), the reaction temperature is between 110-160 °C and the solvents are high boiling aromatic compounds. Possible side-reactions are cis-trans isomerization of 1,4-dienes, attachment of hydrazide fragments to the polymer, degradation and cyclization of the polymer. 

Materials and Methods. First Series. The formula used in most of the tests was 10 pounds of DDT in 5 gallons of a solvent which consisted of a mixture of 2 gallons of carbon tetrachloride and 3 gallons of a high-boiling aromatic petroleum solvent (SV PD 544C)—roughly, a 30% DDT solution. The latter was the predecessor of the special fog oil solution, Sovacide F, that was later developed, which in itself possesses certain insecticidal qualities. 

F-5624A Fuels Containing High-Boiling Aromatic Hydrocarbons, Natl. Advisory Comm. Aeronaut. RM E52G11 (1952). 

Polyterpene resins are related to the oldest reported polymerization, as they were first observed in 1789 by Bishop Watson by treatment of turpentine with sulfuric acid [92]. Commercial polyterpene resins are synthesized by cationic polymerization of /3- and a-pinenes extracted from turpentine, of rf,/-limonene (dipentene) derived from kraft-paper manufacture, and of d-limonene extracted from citrus peels as a by-product of juice industry [1,80,82,93]. The batch or continuous processes are similar for the three monomers. The solution polymerization is generally performed in mixed xylenes or high boiling aromatic solvent, at 30-55° C, with AlCl3-adventi-tious water initiation. The purified feedstream (72-95% purity, depending on monomer) is mixed in the reactor with solvent and powdered A1C13 (2—4 wt% with respect to monomer), and then stirred for 30-60 min. After completion of the reaction, the catalyst is deactivated by hydrolysis, and evolved HC1 is eliminated by alkaline aqueous washes. The organic solution is then dried, and the solvent is separated from the resin by distillation. 

A process for the recovery of Am (and Pu) from these concentrates, based on solvent extraction with tricapryl methyl ammonium nitrate, TCMAN (Aliquat-336, nitrate form), was developed (30), and was operated for some time in a small-scale facility equipped with pulsed glass columns at the Alkem company to produce multi-gram amounts of americium dioxide. In its final version (3JU the process worked as follows The concentrated effluents were made up to 6 to 7 moles/1 nitric acid, and the U and Pu were extracted in the first column by 0,5 moles/1 TCMAN dissolved in Solves-so-100, a high-boiling aromatic diluent. U and Pu... 

In general the paraffinic hydrocarbons possess the mildest odor and the aromatics the strongest, the odor level (ASTM D-268, ASTM D-1296, IP 89) being related to the chemical character and volatility of the constituents. Odors caused by the presence of sulfur compounds or unsaturated constituents are excluded by specification. And apart from certain high-boiling aromatic fractions, which are usually excluded by volatility from the major-... 

A 10% solution of a high boiling aromatic solvent emulsifier with surfactants was used to remove the bulk of free oil by circulation through the heat exchanger. After circulation the unit was drained and flushed. Care would have had to be taken due to the flammability of the solvent and to avoid unacceptable discharge. 

The second procedure for an axial isomerization is thermal conditions. Refluxing of syn biphenyl chromium complexes 65 in high boiling aromatic solvent, e.g., toluene, xylene, mesitylene, for 2 h gave the antz-biphenyl chromium complexes 66 (Eq. 55) [59b,cj. 

TABLE 3 - THE EFFECT OF HIGH BOILING AROMATICS ADDITION ON BaP EMISSION - PERCENT INCREASE OF BaP WITH RESPECT TO "BASE FUELS"... 

PAHs but not the other high boiling aromatics which are listed in Table 4 (20). 

Chem. Descrip. Mixt. of high boiling aromatics, ketones and esters Uses Surf, additive to counteract surface defects, leveling agent for solv.-based coatings, chlorinated rubber systems, silk screen inks Properties Water-wh. liq. aromatic odor sp.gr. 0.86 dens. 7.16 vapor pressure 3 mm Hg flash pt. 43 C ref. index 1.470 <1.0%. in naphtha/ 2,6 dimethyl-4-hepanone/dipentene (14/5/1)... 

Chem. Descrip. Combination of high boiling aromatics, ketones, esters, and a polysiloxane... 

Features High-boiling aromatic HBF [Croda Food Services Ltd]... 

When MBH adducts 169 are heated in a high-boiling aromatic hydrocarbon, they undergo an intermolecular dehydrative double cyclization to produce functionalized 6,8-dioxabicyclo[3.2.1]octanes 171 (Scheme 3.68), which are often present as the basic framework in several pheromones, e.g. frontalin, exo-and endo-brevicomins, ot-multistriatin, However, the stereoselectivity in... 

The boiling point of o-xylene is around 5 °C higher than that of m-xylene, its nearest co-boiling compound. o-Xylene is therefore recovered by fractional distillation in columns with 100 to 150 trays, which requires a reflux ratio of 8-lO.i.The high-boiling aromatics are separated from the o-xylene by distillation in the o-xylene column with 40 to 60 trays and a reflux ratio of around 1 1. 

There is a large number of stages of orientation in the production of carbon products with a graphitic crystalline structure from high-boiling, aromatic residues with the concurrent elimination of hydrogen. 

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