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The nucleation mechanisms in high solids content semicontinuous miniemulsion polymerization was investigated using as case study a silicone−acrylic system. Batch polymerization of the miniemulsion used as initial charge of the reactor was studied. Semicontinuous processes using both miniemulsion feeding and neat monomer feeding were considered. Strategies to maximize the extent of droplet nucleation and to minimize the formation of polymer particles by homogeneous nucleation were discussed. [ABSTRACT FROM AUTHOR]

A telescoped process for the preparation of 2-methoxy-3-methyl-[l,4]benzoquinone is disclosed. When this novel process is compared to the prevailing method that utilizes Na2Cr2O7 as the oxidant, the novel process represents a high yielding (95%), green, and environmentally benign alternative with H2O2 and HNO3 as the oxidants and CH3COOH as the reaction medium. [ABSTRACT FROM AUTHOR]

Mechanistic investigations and protocols for the synthesis of 2-nitrobiphenyls and 2,2′-dinitrobiphenyls are disclosed. It is revealed that obstacles appear during the transmetalation step when the phenylboronic acid is substituted with a nitro group in the 2-position, whereas when substituted in the 3- or 4-positions, the reaction follows similar patterns as found in the electrophilic substitution of nitrobenzenes, an observation that may be attributed to the elimination step of the catalytic cycle. [ABSTRACT FROM AUTHOR]

A novel synthetic process leading to the framework of benzo[c]cinnoline has been discovered and investigated. The process is composed of two separate reactions, the first of which is a partial reduction of the nitro groups of the 2,2′-dinitrobiphenyl, a process that we believe proceeds via a SET mechanism to yield the hydroxyamino and nitroso groups. In the following step the cyclization takes place under formation of the -N=N- bond. We believe that this process take place via a radical mechanism through the nitroso radical anion. The novel process affords either benzo[c] cinnoline or benzo[c]cinnoline N-oxide, both in high yields, 93% and 91%, respectively. To obtain benzo[c]cinnoline, the reaction is conducted with an alcohol as solvent and an alkoxide as the base, while for benzo[c]cinnoline N-oxide, water is used as solvent with sodium hydroxide as the base. To establish the latter procedure, statistical experimental design and multivariate modeling were utilized to reveal the response surface for the reaction and to determine the optimal conditions for the reaction. A proposal for the complex reaction mechanism is given. During the corroboration of the mechanism, a new deoxygenation reaction for converting benzo[c]cinnoline N-oxide into benzo[c]cinnoline was discovered. The reaction is conducted by treating the N-oxide with sodium ethoxide at elevated temperature to achieve near-quantitative conversion into benzo[c]cinnoline in a yield of 96%. [ABSTRACT FROM AUTHOR]