Method for producing alkali metal alcoholates in an electrolysis cell

A process for producing a solution L1 <21> of an alkali metal alkoxide XOR in an alcohol ROH, in an electrolysis cell E <1>, where X is an alkali metal cation and R is an alkyl radical having 1 to 4 carbon atoms, said process comprising the following steps:

• (i) providing an alkali metal cation-conducting solid-state electrolyte ceramic F′ <19> having a surface OF′ <190>;
• (ii) removing a portion of the alkali metal cation-conducting solid-state electrolyte ceramic F′ <19> by compressed air blasting with a solid blasting abrasive N <30>, which produces an alkali metal cation-conducting solid-state electrolyte ceramic F <18> having a surface OF <180> which differs from the surface OF <190> in at least one subregion OFΔ <183>, wherein the surface OF <180> comprises the surfaces OA/MK <181> and OKK <182> and wherein OA/MK <181> and/or OKK <182> comprise at least a portion of OFΔ <183>;
• (iii) arranging the alkali metal cation-conducting solid-state electrolyte ceramic F <18> in the electrolysis cell E <1>, wherein said electrolysis cell comprises at least one anode chamber KA <11>, at least one cathode chamber KK <12> and at least one interposed middle chamber KM <13>;
• wherein the at least one anode chamber KA <11> comprises:
• at least one inlet ZKA <110>;
• at least one outlet AKA <111>;
• and an interior IKA <112> with an anodic electrode EA <113>;
• the at least one cathode chamber KK <12> comprises:
• at least one inlet ZKK <120>;
• at least one outlet AKK <121>;
• and an interior IKK <122> with a cathodic electrode EK <123>;
• and the at least one middle chamber KM <13> comprises:
• at least one inlet ZKM <130>;
• at least one outlet AKM <131>;
• and an interior IKM <132>;
• wherein IKA <112> and IKM <132> are divided from one another by a diffusion barrier D <14>, and AKM <131> is connected by a connection VAM <15> to the inlet ZKA <110>, such that liquid can be passed from IKM <132> into IKA <112> via the connection VAM <15>;
• IKK <122> and IKM <132> are divided from one another by a dividing wall W <16>comprising the alkali metal cation-conducting solid-state electrolyte ceramic F <18>, wherein F <18>makes direct contact with the interior IKK <122> via the surface OKK <182> and with the interior IKM <132> via the surface OA/MK <181>,
• (iv-β) and wherein the following steps (β1), (β2), (β3) proceed simultaneously:
• (β1) a solution L2 <22> comprising the alcohol ROH is routed through IKK<122>, wherein, when OKK <182> includes at least a portion of OFΔ <183>, the solution L2 <22>makes direct contact with the at least on subregion OFΔ <183>;
• (β2) a neutral or alkaline, aqueous solution L3 <23>of a salt S comprising X as cation is routed through IKM <132>, then via VAM <15> through IKA <112>, where, when OA/MK <181> includes at least a portion of OFΔ <183>, the solution L3 <23> makes direct contact with the at least on subregion OFΔ <183>;
• (β3) voltage is applied between EA <113> and EK <123>, thereby providing solution L1 <21> at the outlet AKK <121>, with a higher concentration of XOR than in L2 <22>, and providing aqueous solution L4 <24> of S at the outlet AKA <111>, with a lower concentration of S than in L3 <23>.