Method for the energy-efficient production of sodium and potassium alcoholates

A process for producing at least one alkali metal alkoxide of formula MAOR, wherein R is a C1 to C6 hydrocarbon radical and wherein MA is a metal selected from the group consisting of sodium and potassium, the process comprising:

• (a1) reacting a reactant stream SAE1 comprising ROH with a reactant stream SAE2 comprising MAOH, in countercurrent in a reaction column RRA, to afford a crude product RPA comprising MAOR, water, the ROH, and the MAOH,
• wherein a bottoms product stream SAP comprising the ROH and the MAOR is withdrawn at a lower end of the reaction column RRA, and a vapour stream SAB comprising the water and the ROH is withdrawn at an upper end of the reaction column RRA, and
• (a2) optionally, simultaneously with and spatially separate from (a1), reacting a reactant stream SBE1 comprising ROH with a reactant stream SBE2 comprising MBOH, in countercurrent in a reaction column RRB, to afford a crude product RPB comprising MBOR, water, the ROH, and the MBOH,
• wherein MB is a metal selected from the group consisting of sodium and potassium, and
• wherein a bottoms product stream SBP comprising the ROH and the MBOR is withdrawn at a lower end of the reaction column RRB and a vapour stream SBB comprising the water and the ROH is withdrawn at an upper end of the reaction column RRB,
• (b) passing the vapour stream SAB and, if (a2) is performed, the vapour stream SBB, in admixture with the vapour stream SAB or separately from the vapour stream SAB, into a rectification column RDA, and separating SAB and optionally SBB in the rectification column RDA into an ROH-comprising vapour stream SB2 having a pressure pB2 and a temperature TB2 at a top of the rectification column RDA and a water stream SW at a bottom of the rectification column RDA,
• (c) compressing at least a portion of the vapour stream SB2 to obtain a vapour stream SB3 compressed with respect to the vapour stream SB2, and having a pressure pB3>pB2 and a temperature TB3>TB2, and
• (d) transferring energy from the vapour stream SB3 to at least one selected from the group consisting of the crude product RPA, the reactant stream SAE1, the reactant stream SAE2, the bottoms product stream SAP, and the vapour stream SAB and, if (a2) is performed, alternatively or additionally, transferring energy from the vapour stream SB3 to at least one selected from the group consisting of the crude product RPB, the reactant stream SBE1, the reactant stream SBE2, the bottoms product stream SBP, and the vapour stream SBB, to obtain a vapour stream SB4 having a lower energy content than the vapour stream SB3.