Ethyl benzene solubility parameter

Azad and Fitch (5) investigated the effect of low molecular weight hydrocarbon additives on the formation of colloidafr particles in suspension polymerization of methyl methacrylate and vinyl acetate. It was found that the additives n-octane, n-dodecane, n-octadecane, n-tetracosane and mineral oil exerted a thermodynamic affect depending upon water-solubility and molecular weight. Since these effects on emulsion polymerization have not been considered by the earlier investigators, we have chosen n-pentane and ethyl benzene as additives with limited water-solubility and n-octadecane, and n-tetracosane as water-insoluble ones. Seeded emulsion polymerization was chosen so that the number of particles could be kept constant throughout the experiments and only the effect of the other parameters on the rate could be determined. 

A pump capable of several thousand p.s.i. commonly is used. Not only is the pump needed to maintain supercritical conditions, but the solubilizing power of the system varies greatly with pressure, usually dissolving more solutes as the pressure increases. For example, COj at 1.23 g/em will dissolve eompounds with Hildebrand s solubility parameter (Chapter 41, p. 479) from 7-10, about the same as benzene, chloroform, ethyl acetate, acetone, cyclohexane, carbon tetrachloride, toluene, ethyl ether, and pentane. If the pressure is reduced so that the COj is about 0.9 g/cm then it will dissolve compounds with parameters from 7-9 (solvents like cyclohexane, carbon tetrachloride, toluene, ethyl ether, and pentane) and if further lowered to 0.6 g/cm, it will dissolve only compounds with parameters of 7-8 (ethyl ether and pentane). 

The solubility parameters for toluen e and ethyl benzene are nearly equal, so that the liquid mixture can be considered to be ideal (yi, y2 = 1). Since we do not know a priori whether pure toluene or pure ethyl benzene will freeze out as the solid component from a given mixture, the calculational procedure we will follow is to first assume that toluene appears as the solid component and compute the freezing-point temperature T/ of all toluene-ethyl benzene mixtures. 

FIGURE 3 The dependences of macromolecular coil fractal dimension on polymer and solvent solubility parameters difference A5 for copolymers SAN-MMA. The solvents 1— toluene, 2—ethyl benzene, 3— benzene, 4—chlorobenzene, 5—chloroform, 6—tetrahydrofuran, 7—pyridine, 8—methyl ethyl ketone, 9-1,4-dioxane, 10—N, N-dimethylformamide. The same conventional signs are used in Figs. 4-11. 

The two monomers of major interest, styrene and ethylene, are well known and details can be found on all aspects of their technology elsewhere. Poly(ethylene-co-styrene) is primarily produced via solution polymerization techniques using metallocene catalyst/co-catalyst systems, analogous to the production of copolymers of ethylene with a-olefin monomers. Solvents that can be employed include ethyl-benzene, toluene, cyclohexane, and mixed alkanes (such as ISO PAR E, available from Exxon). The thermodynamic properties of poly(ethylene-co-styrene), including solvent interactions and solubility parameter assessments, are important factors in relation to polymer manufacture and processing, and have been reported by Hamedi and co-workers (41). 

Poly(methyl methacrylate) prepared by free radical polymerization is amorphous and is therefore soluble in solvents of similar solubility parameter. Effective solvents include aromatic hydrocarbons such as benzene and toluene chlorinated hydrocarbons such as chloroform and ethylene dichloride and esters such as ethyl acetate and amyl acetate. Some organic materials, although not solvents for the polymer, cause crazing and cracking, e.g., aliphatic alcohols and amines. Poly(methyl methacrylate) has very good resistance to attack by water, alkalis, aqueous inorganic salts and most dilute acids. Some dilute acids such as hydrocyanic and hydrofluoric acids, however, do attack the polymer, as do concentrated oxidizing acids. Poly(methyl methacrylate) has much better resistance to hydrolysis than poly(methyl acrylate), probably by virtue of the... 

Ethylbenzene and methyl phosphonic acid act as model compounds to parameterize the interaction of beads A and B in models 2 and 3. Separate NPT MD simulations of 500 molecules of each type were carried out at ambient temperature (300 K) and pressure (1 bar). The force field of ethyl benzene was adapted from the PS force field of reference. For methyl phosphonic acid, the force field was taken from simulations of heptylpho-sphonic acid. The heat of vaporization was calculated separately for each type of molecule. The molar volume of each compound was calculated by dividing the molecular weight of the bead by the density obtained from NPT molecular dynamics. The experimental density for methyl phosphonic add was unknown. Therefore, molar volumes for both beads were calculated by MD simulations. The solubility parameters and dg calculated by equation 50 are given in Table 3. The calculated value of % parameter (1.41) from the solubility parameters, which was greater than zero, signifies that ethylbenzene and methyl phosphonic acid should not mix. 

Table 3 Hildebrand solubility parameters for bead A (styrene/ethyl benzene) and B (methyl phosphonic acid) for models 2 and 3. 

Physical Parameters. Paracetamol is obtained as large monoclinic prisms obtained from water having mp 169-170.5°C, and has a slightly bitter taste. It shows 1.293 Mfjnax (ethanol) 250 nm (g 13800). It is found to be very slightly soluble in cold water and considerably more soluble in hot water soluble in methanol, ethanol, DMF, ethylene dichloride, acetone, ethyl acetate slightly soluble in ether and almost insoluble in petroleum ether, pentane and benzene. 

S Physical Parameters. The crystals of clotrimazole has mp 147-149 C. It is a weak base, slightly soluble in water, benzene, toluene soluble in acetone, chloroform, ethyl acetate and DMF. It gets hydrolysed rapidly upon heating in aqueous acids. 

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