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Understanding the details of free radical polymerization (FRP) in multi-component mixtures and solutions is of great importance for the synthesis of polymeric functional materials. Using the framework of dissipative particle dynamics (DPD), we develop a new computational approach to model FRP that couples the reaction kinetics for the polymerization processes to the dynamics of the complex fluid. We specifically consider two mechanisms of chain termination: disproportionation and combination. We analyze the effects of initiation, propagation, and termination on the polymerization kinetics in three-dimensional bulk polymerization by varying the corresponding reaction probabilities. Our model not only allows us to capture the interplay between hydrodynamics and reaction kinetics, but also provides an effective means to model polymerization in the presence of solid inclusions. We demonstrate the latter feature by simulating the formation of polymer-clay nanocomposite gels by FRP in solution in the absence of organic cross-linking agents, where the exfoliated clay particles serve as multi-functional cross-linkers for the polymer network. We observe that increasing the volume fraction of clay particles can lead to an increase in the number of inter-particle cross-linking chains, which could improve the mechanical properties of the material. Our findings provide insight into the polymerization kinetics of the FRP, as well as potential guidelines for tailoring experimental conditions to achieve the desired polymerization products.

The new regioisomer 7-methyl-pyrazolo[4,5-e][1,2,4]thiadiazine nucleus (5) was synthesized, and its novel mono-N2- or N4-substituted pyrazolo[4,5-e][1,2,4]thiadiazines (6, 7) were regioselectively prepared by deprotonation of N2 or/and N4 atoms with different molar ratio of NaH and alkyl halides. Anti-HIV-1 screening tests showed some compounds to be potent as HIV-1 non-nucleoside reverse transcriptase inhibitors (HIV-1 NNRTIs).

Organocatalytic asymmetric direct aldol reactions in brine with high diastereo- and enantioselectivities, using a readily available bifunctional amide catalyst, were developed.Key words: aldol reaction, organocatalyst, asymmetric catalysis, water.

Sterically and electronically tunable and bifunctional organocatalysts have been developed and evaluated in the direct aldol reaction of heterocyclic ketones. Catalysts with different substituents showed variable catalytic efficiency for analogous substrates, indicating the importance of fine-tuning the strength of the hydrogen bonding in the two NH groups. The reactions all proceeded in good to high yield and with excellent enantioselectivities ranging from 90% to >99% ee. In most cases, high diastereoselectivities ranging from 96/4 to 99/1 were obtained for the anti aldol adduct.