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The content and mobility of unreacted methacrylic units in the polymer obtained from trimethylolpropane trimethacrylate, polyTRIM, has been investigated using solid-state NMR techniques. Porous particles of polyTRIM were prepared by suspension polymerization with toluene and isooctane as porogenic agents. The content of remaining double bonds was determined by cross-polarization magic angle spinning (CP-MAS) 13C NMR. In unreacted units, the carbonyl resonance is shifted ca. 10 ppm upfield compared to the reacted units, due to conjugation with the carbon-carbon double bond. A detailed analysis of the cross-polarization behavior showed that quantitative results can be obtained. The amount of unreacted units, typically 0-15%, was found to depend on the polymerization parameters. Conditions favoring mobility, i.e., higher temperatures or increased solvent quality, resulted in lower content of residual double bonds. Bromine addition can also be used to determine the unreacted units, although the obtained values are somewhat higher than the NMR data. The reactivity toward bromine further indicates that the mobility is reasonably high. This has also been confirmed by measurements of the rotating-frame relaxation time constant, Tip(13C). Most likely, T\p is dominated by spin-lattice processes; i.e., it can be interpreted in terms of molecular dynamics. The values obtained for C=0 and >C*=CH2 in unreacted units are about twice that of C=0 in reacted units, indicating increased mobility. The reactivity of the remaining double bonds in a radical polymerization with a chiral monomer was also demonstrated.

Spherical macroporous particles, intended for use as carrier particles in various types of column operations, were prepared by suspension and microsuspension polymerization of trimethylolpropane trimethacrylate (TRIM), in the presence of various amounts of porogenic agents (toluene or mixtures of toluene and isooctane). The texture and properties of the particles varied markedly with the amount and * Systematic UIPAC name: 2,2-bis(methacryloyloxymethyl)butyl methacrylate. 0 1991 Hiithig & Wepf Verlag, Base1 CCC 0003-3146/91/$04.00 113 P. Reinholdsson, T. Hargitai, R. Isaksson, B. Tornell Isooktan) hergestellt. Textur und Eigenschaften der Partikel variierten deutlich mit dem Anteil und der Zusammensetzung des porogenen Reagens und wurden zusatzlich durch die Wahl des Suspensionstabilisators beeinflufit. Die makroporosen Partikel wiesen ein Gesamtporenvolumen von 0,4 bis 3,6 cm3/g und eine spezifische Oberflache von 7 bis >450 m2/g auf. Alle Partikel enthielten Makroporen und, aufier den Teilchen mit sehr niedriger spezifischer Oberflache, einen gewissen Anteil an Mikroporen (Durchmesser < 60 A). Durch Erniedrigung der Monomerkonzentration und Erhdhung des Isooktan-Gehaltes im porogenen Reagens auf 50 Gew.-To konnte das Auftreten von Mikroporen vollstandig unterdriickt werden. Das Erhohen des Isooktan-Gehaltes fiihrte zu einem vergrofierten Gesamtporenvolumen und zu einem verringerten Quellvermogen der Polymermatrix in Toluol. Der Einflufi einer Hitzebehandlung bei 130 "C und eines Aufpfropfens von Polymethylmethacrylat auf die Partikeleigenschaften wurde ebenfalls untersucht. Die Menge an nicht umgesetzten Doppelbindungen in den Partikeln konnte durch Variation der Polymerisationstemperatur verandert werden. Das Vorhandensein leicht zuglnglicher Doppelbindungen ist wichtig, da sie zur Funktionalisierung der festen makroporosen Partikel verwendet werden konnen.

Optical resolving power of chiral stationary phases (CSPs) containing 3,5-dimethylphenyl carbamoylated P-cyclodextrin chemically bonded to silica was compared with those of two commercial stationary phases containing carbamoylated P-cyclodextrin (p-CD), Cyclobond I SN and Cyclobond I DMP. For most of examined 14 racemates, higher selectivities were obtained on our CSPs than on the commercial CSPs. This may be ascribed to the higher degree of substitution of carbamate groups on p-CD and to the opposite orientation of the immobilized p-CD on our materials. The present CSPs were evaluated under reverse, normal and supercritical fluid chromatographic conditions. The highest selectivities were usually obtained under normal phase chromatographic conditions. The influence of cyclodextrins, a-, p -and y-CD, on the enantioselectivity was compared. Each CSP containing different cyclodextrin showed the highest enantioselectivity for different racemates.t Present address:

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