Method for preparing trimethylolpropane by adopting hydrogenation method

The invention provides a method for preparing trimethylolpropane by adopting a hydrogenation method. The method comprises the following steps: performing aldol condensation reaction between n-butanal and a formaldehyde aqueous solution to form a solution containing 2,2-dimethylolbutyraldehyde; performing hydrogenation reaction on the solution containing 2,2-dimethylolbutyraldehyde and hydrogen under the action of a hydrogenation catalyst to obtain a solution containing a product namely trimethylolpropane, wherein the solution containing 2,2-dimethylolbutyraldehyde contains 0.5-3wt% of 2-aldehydemethyl-2-hydroxymethyl butyl methyl ether, and is used as a basic reference. According to the method provided by the invention, a byproduct namely trimethylolpropane methyl ether type substance, which is generated in the process of preparing trimethylolpropane by adopting the hydrogenation method in which the components of the hydrogenation catalyst are used for performing hydrogenation decomposition directly, is optimized, so that the yield of trimethylolpropane is improved.