Polystyrene 2-butanone

For polystyrene in butanone at 67 C the following values of KC2/R0 X 10 were measuredf at the indicated concentrations and angles. Construct a Zimm plot from the data below using k = 100 cm g" for the graphing constant. Evaluate M, B, and from the results. In this experiment... 

The limit of detection for this instrument is about 10 pg/ ml for polystyrene in 2-butanone,163 which is close to two orders of magnitude higher than that of the deflection-type DRI. Moreover, the response of the ELSD is linear over only two decades in concentration.163 The ELSD is a useful backup detector when the DRI or UV detectors are not appropriate, e.g., when the UV absorbance or RI change is a function of copolymer composition as well as concentration or in gradient elution systems where changes in solvent composition cause drift in baselines of the UV and DRI detectors. Compounds about as volatile as the solvent are poorly detected by ELSD. 

A modified rare earth catalyst (30) which is based on a polystyrene backbone as depicted in Scheme 4.15 can be applied even in neat water. It is attached via a hydrophobic oligomeric linker which creates a nonpolar reaction environment and acts as a surfactant for the substrates. The reaction of 4-phenyl-2-butanone with tetraallyltin in water using 1.6 mol% of the scandium catalyst (30) afforded the corresponding homoallylalcohol in a yield of 95%. Interestingly, when using other solvents (dichloromethane, acetonitrile, benzene, ethanol, DMF) the yields decreased drastically, indicating a much higher reaction rate in water [98]. 

The crystallization of the acetone-insoluble polystyrene is completed by boiling for 2 h in freshly distilled butanone it is then allowed to stand overnight at room temperature and finally filtered and dried in vacuum at 60 °C. Yield of crystalline isotactic polystyrene 95-100% of the acetone insoluble portion.The crystalline melting range and the density see Sect. 2.3.4.1) are determined, as is also the limiting viscosity number in toluene at 20 °C. 

Precipitate the polystrene in 50 ml of cold methanol. If desired, it can be purified further by dissolving in 2-butanone and reprecipitating in methanol. When vacuum dried, the polystyrene gives approximately 1.8 g (100% yield). 

Homologous Polymers. As the size of a molecule increases, it is expected that its diffusion coefficient will decrease. Figure 5 shows a plot of D° vs. M for solutions of polystyrene in 2-butanone (methyl ethyl ketone) where the relationship between D° and M may be expressed by the semiempirical formula... 

The dependence of retention in Th-FFF on chemical composition of the polymers and solvent [84] also opens a wide field of application for Th-FFF, especially for copolymers. According to Eq. (42), retention in Th-FFF can be used to determine the thermal diffusion factor aT which was demonstrated for polystyrene in toluene [209]. Eater, this study was extended to other solvents (ethyl acetate, 2-butanone, p-dioxane, cyclohexane, dimethylformamide, chloroform, and ethylbenzene) [204]. 

Wolf, B. A. Breitenbach, J. W. Senftl, H., "Upper and Lower Solubility Gaps in the System Butanone-Acetone-Polystyrene," J. Polym. Sci., Part C, 31, 345 (1970). 

Syndiotactic polystyrene prepared with tetrabenzyltitanium or tetrabenzyl-zirconium and methylalumoxane was analysed by I3C NMR in regard to end-groups.155 A boiling butanone-soluble low molecular weight fraction shows signals due to both chain ends as shown below ... 

Simple diols have been subjected to the pinacol rearrangement in the presence of Amberlyst 15, a polystyrene sulfonic resin with a high concentration of acidic centers. When excess catalyst is used (g catalyst/g diol = 1.25) pinacol gives 3,3-dimethyl-2-butanone in near quantitative yield (batch reactor, 373 K, 2 h) [33]. Of the two isomeric ketones 3,3-diphenyl-2-butanone (10), formed with phenyl migration, is the sole product when 2,3-diphenyl-2,3-butanediol (9) is reacted (Scheme 6). This feature is very similar to that observed under homogeneous conditions in the presence of sulfuric acid [2]. An arylsulfonic silica catalyst prepared by grafting and sulfonation proved to be less selective [33]. 

From these data determine the second virial coefficient and the theta temperature of poly(a-methyl styrene) in cyclohexane, knowing that K = K hl AhlAcf, where K = 18.17 mol cm , the refractive index increment (d /dc) is 0.199 ml gr, and the temperature dependence of the refractive index is expressed by = -0.0005327 x T (°C) + 1.446. Static light-scattering measurements were carried out by Zimm (1948b) on polystyrene in butanone at 340 K at two concentrations. 

Wolf,B. A., Breitenbach,J.W., SenfU,H. Upper and lower solubility gaps in the system butanone/acetone/polystyrene. J. Polymer Sd. C (Symposia) 31, 345 (1970). 

Typical light-scattering data for polystyrene in butanone are plotted in Fig. 1.59 in a method which was suggested originally by Zimm [20,21]. The abscissa is... 

The synthesis of polystyrene with a liighly syndiotactic microstructure (Scheme 22.7) was achieved for the first time by Ishihara in 1986 with a catalyst consisting of a titanium precursor and aluminum activator. Roughly 98% of the polymer was insoluble in 2-butanone, and this material had an rrrr-pentad content greater that 98%. Many simple titanium catalysts activated by MAO were later shown to generate syndiotactic polystryrene. Tetrabenzyltitanium, when activated by MAO, catalyzes the polymerization of styrene to form a syndiotactic material with greater than 98% rr triads. Tetrahalo and tetraalkoxo titanium compounds also form syndiotactic polystryene when activated by MAO, but the activity of these catalysts was relatively low. 

Vapor-liquid equilibrium data of polystyrene in 2-butanone and methanol... 

Table 1 Coexistence data of polystyrene (Mn/(g/mol) = 133000, Mw/(g/mol) = 233000) in 2-butanone (C4HgO) and methanol (CH4O) at T= 303.15 K [2001WUE1],...

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