Energy recovery in a method for preparing 1,3,5-trioxane

A process for energy recovery in a process for the preparation of 1,3,5-trioxane comprising the steps

• a) reacting formaldehyde in the presence of water and at least one acidic catalyst in a first reactor to obtain a first product mixture, which comprises water and 1,3,5-trioxane, wherein the first product mixture is transferred as a first stream from the first reactor to a distillation tower,
• b) contacting the first product mixture with at least one extractant in the distillation tower to obtain an overhead product, and a side cut, wherein the overhead product comprises the at least one extractant and water, and wherein the side cut comprises the at least one extractant and 1,3,5-trioxane, wherein the overhead product is transferred as a second stream from the distillation tower to a mechanical compressor, wherein the second stream has a first temperature and a first pressure,
• c) mechanical compression of the second stream in the mechanical compressor to obtain a compressed stream, which has a second temperature and a second pressure, wherein the second temperature of the compressed stream is higher than the first temperature of the second stream and wherein the second pressure of the compressed stream is higher than the first pressure of the second stream,
• d) transferring heat from the compressed stream to the first reactor.