Benzene styrene, molar concentrations

Chromatography by ion exchange on a sulfonated poly(styrene-co-divinyl benzene) phase has been proposed as a replacement for titrimetry.57 Eluted by a dilute solution of a neutral salt such as sodium ethanesulfonate, the conductance of the protons can be measured in the absence of a suppressor from sub-millimolar to molar concentration. The response factors of mono-, di-, and trichloroacetic acid and of o-phthalic acid were large and essentially equivalent to ethanesulfonic acid, while the response factor of acetic acid was far smaller. A syringe pump has generated pressures as high as 72,000 psi (5000 bar) in a capillary column packed with 1 p particles, generating a fraction capacity of 300 peaks in 30 minutes.58... 

Fig. I. Concentration of styrene monomer (A) and polystyryl-lithium (B) in arbitrary units during a polymerization of 1.4 x 10 molar styrene with 1.1 x 10 molar butyllithium in benzene...

Fig. 5. Effect of tetrahydrofuran on the propagation rate in the polymerization of styrene in benzene. Concentration of polystyryHithium, o I.l x 10 molar, x 1.4 x 10 molar...

Figure 1. Rate of formation of polystyryllithium at about 7 x 10 A molar butyllithium o—benzene at 30° C., [styrene] = 0.0067M —cyclohexane at 40° C., [styrene] = 0.253M. Note the much higher styrene concentration required in cyclohexane to produce a similar rate.

MCM-41 analogue metallosilicates containing the redox aetive metals V, Co, Cr and Ni or bimetals VCo and CrNi have been synthesized from aqueous gel by hydrothermal treatment. The mono- and bimetallic molecular sieves were eharacterized by various techniques, such as XRD, N2 adsorption-desorption, SEM, TEM and FTIR spectroscopy. The catalytic activity in the selective oxidation of styrene and benzene with H2O2 has been evaluated. The catalytic properties and the characteristics of the structure were correlated with the synthesis conditions, the nature and concentration of the metal, the association of two metals and their molar ratio in the bimetallic incorporated silicates and the oxidation state of the metal cations in the precursors. 

The gas phase alkylation of toluene with methanol was carried out in a fixed-bed tubular reactor at atmospheric pressure. Samples were sieved to retain particles with 0.35-0.40 mm in diameter for catafytic measurements. A mixture of toluene/methanol of 1 1 molar ratio was vaporized in a preheating section and delivered to the reactor. The reaction was carried out at 400 °C, employing a space velocity (WHSV) of 2 h. Toluene conversion (Xtoi) was calculated as Xtoi (%) = [EYj / (ZYj + Ytoi.)]100, where ZYj is the molar fiactions of the aromatic reaction products, including benzene, and Ytoi is the outlet molar fiaction of toluene. The selectivity to product j was determined as Sj (%) = [Y/EYj.lOO. The Sei-bz selectivity includes the sum of ethylbenzene and styrene, which are the side-chain alkylation products. In-situ poisoning experiments were carried out by doping the toluene/methanol mixture with either acetic acid or 3,5-dimethyl pyridine in a concentration range between 0-15000 ppm... 

Figure 4-19. Change of the z average root mean square radius of gyration ( Rg) with concentration for poly(styrene) in benzene at 20° C and various molar masses (after H. Dautzenberg).

The polymerization of styrene in solution [53,58] and bulk [54,55,59—61] by the redox system benzoyl peroxide-di-n-alkylaniline has been studied considerably by many researchers. Different dialkylanilines (DAAs) such as dimethylaniline (DMA), diethylaniline (DBA), di-n-butylanilines, di-n-oc tylaniline, and di-n-decylaniline combined with benzoyl peroxide have been studied for the solution polymerization of styrene [58] in benzene at 30 C. It was found that the initial rate of polymerization increased with a decrease of the molar ratio of BZ2O2/DAA for a specific concentration of monomer and BZ2O2. The degree of polymerization decreased with the decrease of molar ratio of BZ2O2/DAA. The initiator efficiency seemed to increase gradually with the number of carbons of the alkyl groups in the DAAs, with the exception of di-n-octylaniline. 

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