Abstract: A method for synthesizing beta-dicarbonyl compounds, particularly beta-diketones, from at least two carbonyl compounds, such as esters and ketones, in the presence of a strong base or a mixture of strong bases by Claisen condensation with a titer of greater than 95%. The method includes providing a synthesis reactor on which a separation column, provided with a condenser and with at least one microwave generator, is mounted; feeding a first carbonyl compound and the strong base into the synthesis reactor; heating the reactor and starting up the condenser; starting up the microwave generator(s); when the mixture is brought to a boil at total flux, feeding the second carbonyl compound into the reactor; and after a waiting time, stopping the reactor and acidifying and washing the reaction mixture.

Abstract: This invention relates to a process for the preparation of aqueous emulsions of blocked (poly)isocyanates, this process comprising the steps consisting successively in: a) placing an isocyanate composition containing free isocyanate functions in contact with at least one blocking agent A in the presence of a surfactant B and an aqueous phase, the said isocyanate composition being added gradually to a stock containing at least some of the aqueous phase and at least some of the blocking agent; and optionally, b) subjecting the mixture obtained to a shear (speed gradient) of greater than 1000 s?1, preferably greater than 20,000 s?1 and less than 1,000,000 s?1, preferably less than 200,000 s?1, and c) repeating step b), optionally after step a) has been repeated, until a stable emulsion is obtained whose particles have a Sauter diameter of greater than 0.1 ?m, preferably 0.2 ?m, and less than 5 ?m, preferably less than 2 ?m, and a dispersion width of less than 5 ?m.

Abstract: This invention relates to a process for the preparation of aqueous emulsions of blocked (poly)isocyanates, this process comprising the steps consisting successively in: