3results about How to "Size limit" patented technology

The application discloses a kind of for methanol and methyl methacrolein oxidation esterification catalyst and its preparation method and application, belong to catalytic synthesis technical field.The application first prepares silicon-titanium molecular sieve TS-1 carrier, then loads gold nanoparticles, and gold-based catalyst is prepared, TS-1 carrier can not only stabilize gold salt, Ti-O-Au bond can be formed between titanium species in TS-1 carrier and gold nanoparticles, improve the interaction between gold metal and carrier, more effectively limit the size of gold particle, form smaller size nano gold particle and good dispersity, improve the specific surface area of catalyst, to improve catalyst activity and stability.Mass concentration is 45-80% methanol and methyl methacrolein mixed solution and the obtained catalyst are mixed sufficiently, oxygen is input, and oxidation esterification reaction occurs under 70-160 DEG C, 0.5-2MPa, to prepare methyl methacrylate.The gold-based catalyst prepared by the application significantly improves the conversion rate of methyl methacrolein and the selectivity of methyl methacrylate.

This utility model discloses a color-mixing flash wheel, comprising: a wheel fork bracket and rivets. The wheel fork bracket has annular synchronous positioning components on both sides. Each set of synchronous positioning components has an annular flange on its outer side. A first bearing is mounted on the synchronous positioning component. A positioning light ring is mounted outside the first bearing. An annular circuit board is mounted inside the positioning light ring. The circuit board is electrically connected to multiple flash lamps, which emit multiple colors of light. A wheel core is mounted outside the positioning light ring. A second bearing is mounted outside the wheel core. The outer edge of the wheel core is recessed inward to form a placement groove adapted to the flash lamps. The flash lamps are connected to the circuit board via bent metal wires. The metal wires extend above the placement grooves to facilitate the placement of the flash lamps within the grooves. This utility model solves the defect that the small size of the light lamps prevents the mixing of multiple colors of light as the wheel rotates.

The invention belongs to a method for preparing melamine cyanurate by taking alkali metal salt as a catalyst. The method comprises the following steps: premixing raw materials; sequentially adding deionized water and melamine into the four-neck flask, and heating the system to 55 DEG C on the basis of sufficient stirring; step 2, adding cyanuric acid and an alkali metal salt catalyst into the system heated to 55 DEG C; step 3, heating the materials to 90 to 100 DEG C; continuously stirring for 1.5-3 hours to ensure that the reaction is uniform; step 4, cooling a product after the reaction to room temperature, separating out a solid-phase product through filtration, and washing with deionized water to remove unreacted raw materials and the catalyst, so as to obtain a washed product; step 5, drying and crushing the washed product to obtain melamine cyanurate with the purity not lower than 99%; the method has the characteristics that the reaction temperature and reaction time are reduced, side reactions are reduced, the yield is improved, and the product is high in purity and small and uniform in particle size.