5 results about "Isomerization" patented technology

The invention provides an n-alkene isomerization catalyst. The catalyst contains 50-90% (by mass) of a molecular sieve and the balance aluminum oxide; the molecular sieve is composed of SAPO-11 and ZSM-5, wherein SAPO-11 accounts for 75-90% (by mass) of the total mass of the molecular sieve, and ZSM-5 accounts for 10-25% (by mass) of the total mass of the molecular sieve; the microparticle size of the molecular sieve in the catalyst is 1-2 micrometers. The catalyst has high n-alkene isomerization activity, the isoalkene yield is high and can be maintained for a long time, a long one-way running cycle is achieved, the decreasing amplitude of regeneration performance obtained after multiple times of scorching is small, and the catalyst is suitable for the process of preparing isobutene from n-butene through an isomerization reaction and the process of preparing isopentene from n-pentene through an isomerization reaction and particularly suitable for the process of preparing isobutene through post-etherification C4 n-butene isomerization.

The invention provides a method for preparing 5-methylthienyl-2-thiol from levulinic acid, relating to thiophene compounds. The method comprises the following steps: adding levulinic acid into a solvent, and adding a Lawesson reagent to react; washing the product with an alkali, neutralizing 4-methoxyphenylphosphonic acid to obtain a salt, and transferring the salt into a water phase, wherein the target product 5-methylthienyl-2-thiol is retained in an organic phase and separated from the 4-methoxyphenylphosphonic acid; and carrying out reduced pressure distillation on the organic phase to obtain the 5-methylthienyl-2-thiol. The raw material reacts with the Lawesson reagent, and the 5-methylthienyl-2-thiol can be prepared by a cascade thionation-cyclization-isomerization process in one reaction procedure, so the steps are simple. The sodium carbonate or sodium bicarbonate solution is used for washing, so that the Lawesson reagent residue 4-methoxyphenylphosphonic acid can be effectively removed on the premise of not influencing the target product 5-methylthienyl-2-thiol. The obtained product has abundant reaction sites, such as aromatic thiophene rings, mercapto groups and the like, and has high plasticity.

The invention relates to a catalyst for preparing alpha-acetoxyacetone by hydroformylation of vinyl acetate, the catalyst is generated in situ by a rhodium precursor, a phosphine ligand and an alkali metal salt aid in the presence of a solvent, and in the presence of the solvent, the alkali metal salt modified phosphine ligand and the rhodium precursor are coordinated to form a rhodium-phosphine catalyst system. Aiming at the current situation that a traditional vinyl acetate hydroformylation catalyst does not have isomerization catalytic reaction activity and cannot directly synthesize alpha-acetoxyacetone, the catalyst provided by the invention is characterized in that an auxiliary alkali metal salt is introduced into a rhodium-phosphine complex catalyst system; the purpose of catalyzing the generation of the hydroformylation product 2-acetoxypropionaldehyde of vinyl acetate and rapidly carrying out isomerization reaction to synthesize alpha-acetoxyacetone is achieved.