Method for preparing pinacolone

A method for preparing pinacolone, comprising:

• reacting raw materials in the presence of a catalyst to produce pinacolone;
• wherein the raw materials comprise 2-methyl-2-butene, hydrochloric acid and formaldehyde;
• the catalyst is a single lanthanide Lewis acid, a compounded lanthanide Lewis acid, or a lanthanide metal oxide soluble in hydrochloric acid;
• the single lanthanide Lewis acid is selected from the group consisting of lanthanum chloride, cerium chloride, praseodymium chloride and neodymium chloride;
• the compounded lanthanide Lewis acid is a combination of a first component and a second component;
• wherein the first component is selected from the group consisting of lanthanum chloride, cerium chloride, praseodymium chloride and neodymium chloride;
• the second component is selected from the group consisting of lanthanum chloride, cerium chloride, praseodymium chloride, neodymium chloride, erbium chloride, holmium chloride, dysprosium chloride, thulium chloride, and a combination thereof;
• and the second component is free of a compound selected as the first component;
• a molar ratio of the first component to the second component in the compounded lanthanide Lewis acid is 1-50:50-1;
• and
• in a case that the second component is a combination of two compounds respectively selected from the group consisting of lanthanum chloride, cerium chloride, praseodymium chloride, neodymium chloride, erbium chloride, holmium chloride, dysprosium chloride and thulium chloride, a molar ratio of the first component to one of the two compounds to the other of the two compounds is 1-5:1-3:1-3.