716results about How to "Short holding time" patented technology

The invention provides a connection method for carbon steel and zirconium oxide ceramic. In the method, pulse current is mainly applied to carbon steel, zirconium oxide ceramic and a titanium foil active intermediate layer to perform discharge plasma connection by using discharge plasma sintering equipment; and the discharge plasma connection has the following technological parameters that: the axial pressure is 10-50MPa; the temperature raise rate is 50-600 DGE C / min; the connection temperature is 800-1,100 DEG C; the temperature keeping time is 10-50 minutes; and vacuum degree in a furnace chamber is 6-10Pa. The invention also provides a connecting piece for the carbon steel and the zirconium oxide ceramic manufactured by the connection method.

The invention discloses a method for preparing sucralose-6-ester by utilizing a phase transfer catalyst to catalyze and chloridize. The method comprises the following steps: adding the phase transfer catalyst in a prepared Vilsmeier reagent, and dropwise adding a DMF (Dimethyl Formamide) solution of sucrose-6-ester at 5-10 DEG C; raising the temperature to 45-55 DEG C, and keeping the temperaturefor 1-1.5 hours; raising the temperature to 75-85 DEG C, and keeping the temperature for 1-1.5 hours; raising the temperature to 108-109 DEG C, keeping the temperature for 2.5-3 hours, reducing the pressure, concentrating and evaporating a chlorine-containing solvent; reducing the temperature of material liquid to room temperature; and introducing ammonia, thereby neutralizing. The method provided by the invention has the beneficial effects that the energy consumption can be reduced, the low-temperature reaction is stable and safe, the final temperature of the reaction is low and the generation of by-products is reduced. During a treating process after chloridizing the material liquid, the ammonia is introduced for neutralizing, thereby achieving zero carried water and reducing the decomposition and loss of the sucralose-6-ester. Meanwhile, the recycling cost of the solvent DMF is lowered, the energy consumption during production is reduced, and the phase transfer catalyst is used forboosting the efficient dissolving of the raw material and causing the chlorination reaction to be stably and efficiently carried out.