Method for preparing tpo compound and co-producing 3-hydroxyalkyl-substituted oxetane compound

Disclosed is a method for preparing a compound of formula (I) and co-producing a compound of formula (II), wherein the method comprises the following steps: 1) reacting a compound of formula (III) with a compound of formula (IV) in the presence of an organic or inorganic base to obtain a compound of formula (V), and 2) reacting the compound of formula (V) with a compound of formula (VI) to obtain the compound of formula (I) and co-produce the compound of formula (II), wherein R1, R2, R3, R4, m, n, p, M, X and X' are as defined in the description. The method not only avoids the problem of recovering the large amount of organic waste gas, i.e. methyl chloride and ethyl chloride, involved in the production of a TPO compound, but also avoids the problem of the recovery processing of the large amount of organic waste water involved in the production of a 3-hydroxyalkyl-substituted oxetane compound. Moreover, the whole process has a low preparation cost, a simple operation process and a safe reaction process, is easy to control and environmentally friendly, easily achieves large-scale production, and has industrial production value.