| 摘要 |
The invention relates to a method for the production of polyesters or copolyesters, wherein continuos esterification of dicarboxylic acid esters and diols or continuos interesterification of dicarboxylic acid esters with diols is carried out in n reaction pressure levels connected one after the other, wherein the pressure in the first reaction pressure level, which is higher relative to the other reaction pressure levels, drops successively from one reaction pressure level to the other, the vapor flows of the individual reaction pressure levels are jointly rectified in a rectifying column and the diol components falling to the bottom of the rectifying column are fed back again at least to the first reaction level. In order to reduce the degree of complication of said process, at least the last reaction pressure level has a negative pressure, the pressure in the rectifying column is higher than the pressure in the last reaction pressure level and the vapors coming out of the last reaction pressure level are compressed to the pressure prevailing in the rectifying column.
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