Benzene properties/recovery

Solubility — the amount of a given substance (the solute) that dissolves in a unit volume of a liquid (the solvent). This property is of importance in the handling and recovery of spilled hazardous materials. Water-insoluble ehemicals are much easier to reeover from water than spills of water-soluble chemicals. Acetone, which is miscible/soluble in water in all proportions, is not readily reeoverable from water. In contrast, benzene, which is lighter than water and insoluble as well, can be readily trapped with a skimmer. For organie eompounds, solubility tends to deerease with inereasing moleeular weight and ehlorine content. 

Etliylene production involves liigh temperatures (1500°F) in tlie pyrolysis section and cryogenic temperatures in tlie purification section. The feedstocks, products, and by-products of pyrolysis are flaimnable and pose severe fire liazards. Benzene, wliich is produced in small amounts as a byproduct, is a known carcinogen. Table 21.7.1 summarizes some of the properties of etliane (feedstock) and tlie product gases. Figure 21.7.1 shows a simplified schematic diagram of the pyrolysis and waste heat recovery section on an etliylene plant. 

These facts suggest that variable recoveries of parathion from the evaporation procedure, as used routinely, should be expected. In general, however, the recovery data did not demonstrate a clear-cut distinction between acetone and benzene for the purpose at hand. A slow steady loss of parathion in proportion to the volume of either solvent evaporated (1) was not noted, which would indicate that the rate of evaporation is also important. The final decision as to solvent was determined by certain incidental properties of the parathion. 

Effects of Alcohols. Alcohols are common additives to many surfactant formulations being considered for oil recovery. Wade (12) has studied the effect of alcohol additions on interfacial properties and phase behavior for pure alkyl benzene sulfonates. 

The use of supercritical fluid extraction (SEE) as an extraction technique is related to the unique properties of the supercritical fluid. These fluids have a low viscosity, high diffusion coefficients, low toxicity, and low flammability, all clearly superior to the organic solvents used in SPE extraction. The most common fluid used is carbon dioxide. SEE extractions of sediment samples have shown recoveries of >95% for all the individual PCBs. The separation of PCDDs from PCBs and chlorinated benzenes is difficult because of their similar solubility. An interesting development is the use of fat retainers. Samples, mixed in different weight ratios with, e.g., silica/silver nitrate 10% or basic alumina, can be placed in 7 ml extraction cells. The analytes are recovered by elution with 1.5-1.8 ml of hexane. With the correct fat-silica ratios and SEE conditions, no additional cleanup procedure is necessary for GC with an electron-capture detector (ECD). One drawback of SEE may be that the methods developed are valid for a specific matrix, but as soon as, e.g., the fat content of a biota sample or the type of lipids changes, the method has to be adapted. SEE is relatively complicated compared to other extraction techniques. In addition, the cell volumes are small, which limits the sample intake, and, with that, the detection limits. Einally, some reliable types of SEE equipment have recently been withdrawn from the market. This will have a substantial negative effect on the use of SEE in the near future. 

Cunninghame and Miles determined the extraction properties of a number of possible impurities in the development of a batch process for separating Pu from irradiated U. Their results are shown in Fig. 37. Their procedure, which should be easily adaptable to the laboratory scale, is to pre-extract the Zr from 0.5 M HNOj while the Pu is reduced to Pu(III) with hydroxylamine, oxidize to Pu(IV) with NaNO, extract with 0.2 M TTA-benzene, scrub with dilute HNOg, and back-extract the Pu into 8 M HNOg. They report a 99.4% Pu recovery on a 1-gram scale with decontamination factors from Zr and U of 3000 and 667, respectively. 

Selective adsorption properties are obtained from the structure, controlled distribution of pore sizes, high surface areas and chemical nature of the matrix. Applications include the recovery of a wide range of solutes from the aqueous phase, including phenol, benzene, toluene, chlorinated organics, PCBs, pesticides, antibiotics, acetone, ethanol, detergents, emulsifiers, dyes, steroids, amino acids, etc. Regeneration may be effected by a variety of methods which include steam desorption, solvent elution, pH change and chemical extraction. 

The operation of Fig. 11-2 shows conditions for diesel fuel (5,000 bpd) extraction, but the same plant has been operated on kerosene (5,000 bpd) and naphtha (4,100 bpd). Table 11-3 indicates the yields and properties during operation for diesel fuel. The process has also been applied to catalytic cycle oils and to the recovery of benzene and toluene from catalytic reformates. ... 

Chem. Descrip. 70% mono substituted C20-24 benzene Uses Intermediate for sulfbnatlon to produce dispersants, emulsifiers, rust preventives, crankcase additives, demulsifiers, ore flotation collectors, textile chems., degreasers, enhanced oil recovery chems. used In emulsion polymerization, lubricating grease mfig., metalworking, cleaners Properties Lt. color mild odor m.w. 450 vise. 34 cSt (100 F) i.b.p. 560 F pour pt. 65 F flash pt. (COC) 420 F dielec, const. 2.1-2.2 AristolB [Pilot]... 

---