Ind. Eng. Chem.
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Prod. Res. Dev. 1904, 23, 240-245
Table 11. Emulsion Polymerizability of Monomers Initiated by Ti3+/H,NOHa ____run no. monomer polymer yield, % _ _ _ _ I -
__ ___
.
73 76 LC 88 87
styrene acrylonitrile vinyl acetate' methyl methacrylate is0 pre ne
91.3 52 85 lOOb
8.0
a All runs at 30 ' C , 100.0 m L of water, 20.0 mL of monomer, 1.00 g of DTMACI, 1.58 M Ti(II1) and NH,OH, injected through 20 0.1-mL injections at 15-min intervals. Percent yield difficult t o determine due t o much precipitated polymer. 2.0 g of DTMACl used. Initiator concentration: 0.88 M with 15 0.1-mL injections at lO-min intervals.
ion and/or hydroxylamine form such complexation or adsorption could account for the need for long injection intervals. Continued experiments are being directed at determining the details of the initiation process. Effect of Polymerization Temperature. There appears to be a direct relation between polymer yield and reaction temperature. Emulsion polymerization conducted at 0 "C gave a poly(styrene) yield of 55%; at 30 "C: 77%; and at 60 "C: 85%. All polymerizations were conducted by using 1 g of DTMACl and 15 0.1-mL injections of 1.3 M initiators. Polymerizability of Various Monomers. Using the optimum conditions for styrene polymerization, an attempt was made to polymerize the four monomers: acrylonitrile, methyl methacrylate, vinyl acetate, and isoprene. Styrene is also included for comparison, except that 2.0 mL of initiators was injected in 0.1-mL increments to increase the poly(styrene) yield above 90%. The results of the monomer studies are shown in Table 11. Acrylonitrile gave a very unstable (much preciptate) product which appeared to be composed of tiny particles, indicative of a suspension polymerization. The methyl methacrylate product was very thick but smooth in consistency. Vinyl acetate gave a normal appearing latex, much like that of the styrene system.
Summary These studies show that styrene and other common vinyl monomers may be polymerized in an emulsion system using the redox initiating system titanium trichloridehydroxylamine. Cationic emulsifiers give the most satisfactory yield of polymer and the initiators must be introduced incrementally. Styrene could be polymerized to over 90 % yield of latex. Vinyl acetate behaved similar to styrene. The methyl methacrylate product was thick and unstable, while acrylonitrile may not have polymerized by a true emulsion mechanism. Further study will have to be made to optimize polymerization conditions for each monomer type and additional research is needed to determine the initiation mechanism in an emulsion environment. Registry No. TiC13, 7705-07-9; Triton X-100, 9002-93-1; hexadecyltrimethylammonium chloride, 112-02-7;hydroxylamine, 7803-49-8;poly(styrene) (homopolymer), 9003-53-6; poly(acry1onitrile) (homopolymer), 25014-41-9; poly(methy1 methacrylate) (homopolymer), 9011-14-7;poly(viny1 acetate) (homopolymer), 9003-20-7; poly(isoprene) (homopolymer), 9003-31-0; dodecyltrimethylammonium chloride, 112-00-5.
Literature Cited Albisetti, C. J.; Coffman, D. D.; Hoover, F. W.; Jenner, E. L.; Mochel, W. E. J . Am. Chem. SOC. 1050, 81, 1489. Blazek, A.; Koryta, J. Collect. Czech. Chem. Commun. 1053, 18, 326. Davis, P.; Evans, M. G.; Higglnson, W. C. E. J . Chem. SOC. 1051, 2563. Fischer, 0.; Dracka, 0.: Fischerova, E. Collect. Czech Chem. Common. 1061, 26. 1505. Herman, H. B.; Bard, A. J. Anal. Chem. 1064, 36, 510. Howard, E. G. U S . Patent 2587 109 (duPont), Sept 4, 1951. Izumi, 2 . ; Ranby, B. Macromolecules 1075, 8 , 151. Kakurai, T.; Iwai, S.; Noguchi, T. Kobunshl Kagaku 1066, 23, 279. Kakural, T.; Sugata, T.; Noguchl, T. Kobunshi Kagaku 1068, 120. Lingane, P. J.; Christie, J. H. J . Nectroanal. Chem. 1067, 13, 227. Minisci, J.; Galli, R. Tetrahedron Lett. 1065, 1879. Pierson, R. H.; Gantz, E. St. C. Anal. Chem. 1054, 26, 1809. Rubio, S.; Serre, J.; Sledz, J.; Schue, F.; ChaD9let-LetOUrneuX, G. Polymer 1081, 22, 519. Seaman, H.; Taylor, P. J.; Waters, W. A. J . Cbem. SOC. 1954, 4690. Serre, B.; Rubio, S.; Siedz, J.; Schue, F.; Chapelet-Letourneux, G. Polymer 1081, 22, 513.
Received for review July 22, 1983 Accepted December 1, 1983
Stereographic Display of Three-Dimensional Solubility Parameter Correlations David L. Wernlck Corporate Research, Exxon Research and Englneerlng Company, Annandale, New Jersey 0880 1
Correlations of solution properties with Hansen's three-dimensional solubility parameter are not adequately displayed in two-dimensional graphs. The need for laborious construction of threedimensional scale models is eliminated by computer simulation and stereographics. Data points are rotated to the desired viewing angle and projected as a stereopair. Levels of the dependent variable (e.g., solubility) are represented by differing plot symbols. Correlations of magnesium nitrate solubility, cellulose acetate solubility and solution viscosity, benzene activity coefficients, tert-butyl chloride solvolysis rates. 9,1Odibromoanthracene fluorescence lifetimes, and activated carbon adsorption equilibria are illustrated.
It has become clear in recent years that one-dimensional solvent parameter scales such as Kosower's 2, Dimroth et al.'s E,, Hildebrand's 6, or dielectric constant cannot adequately correlate the entire range of solvent effects of interest to chemists (Kamlet et al., 1981; Hildebrand et 0196-4321/84/1223-0240$01.50/0
al., 1970). Several workers have therefore proposed two-, thee-, four-, or even five-dimensionalscales based on linear free energy relationships (Kamlet et al., 1981), on factor analysis (Cramer, 1980), or on cohesive energy density concepts (Barton, 1975; Blanks and Prausnitz, 1964). 0 1984 American
Chemical Society
Ind. Eng. Chem. Prod. Res. Dev., Vol.
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23,No. 2, 1984 241
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6,
6,
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0 6
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6, 6, Figure 1. Orthogonal projections of Mg(N08)2.6H20solubility vs. 6 of solvent: (0)1 1g/g of solvent; (*) 0.4-1; (A)0.2-0.4; ( X ) 0.1-0.2; ( 0 ) 5% solubility; (*) polymer swells; (A) insoluble. Axes and tickmarks as in Figure 2.
above simulates such models by rotation of the data to desired points of view and stereoprojection. The resulting
P
stereographs, identical in principle to steroviews of molecular structures commonly used in crystallography, convey all the information of the solid model. One can thus determine solubility regions and examine other 6 correlations with full generality and with little effort. The convenience of the stereographic approach should be emphasized. Our program, which called upon the SAS statistical and graphics software package, had a length of only 83 lines and an execution cost under $1. A good stereograph was usually produced with - 2 h of labor, including time for data input, editing, and selection of an optimal perspective. Comparable performance is expected on any system with modern graphics software and high resolution hardware. Examples of 6 correlations have been chosen to illustrate applications to diverse chemical phenomena as well as the advantages of stereographical display. Discussion of the chemical significance of each correlation has been limited to that which seems warranted by current theoretical understanding. Detailed inferences from the shape of solubility contours, etc., must await a deeper understanding of the physical properties measured by bH, b p , and bD. Likewise, fitting arbitrary nonlinear equations to the data serves little scientific or statistical purpose in the absence of a theoretical functional form relating 6 to the phenomenon under investigation. Solubility of Magnesium Nitrate. Solubility of a salt presents a demanding test of the Hansen system and of graphical display techniques since 6 values were not originally assigned to correlate properties of ionic solutes. Orthogonal projections of Mg(N0J2-6H20 solubility (Hansen, 1969) in 28 organic solvents, including alcohols, ketones, amides, ethers, hydrocarbons, chlorinated hydrocarbons, acetic acid, y-butyrolactone, and dimethyl sulfoxide, are plotted in the manner recommended by Hansen in Figure 1. Although it is clear from any of the two-dimensionalplots that solubility correlates with 6, the shape of solubility contours cannot be discerned, nor can the quality of the correlation be evaluated. Recognizing these difficulties, Hansen (1969) suggested either building a solid model or assuming spherical contours (represented as circles on the scale of Figure 1) about a center found by trial and error. Figure 2 is a stereograph of the same data. The clustering of points at each solubility level, indicating a good correlation with 6, is immediately apparent. It is clear that solubility increases with increasing 8H and 8p; evidence for or against a dD effect is lacking without additional data.
0
t Figure 4. Stereograph of cellulose 2.45-acetate solubility and viscosity of 15% solutions vs. 6 of solvent at 25 'C: (0) 176-190 cP; (*) 335-864 cP;(A) 1530-9650 cP; ( X ) 16800 cP; ( 0 )
