English to Russian Law/Patents Chemistry; Chem Sci/Eng Получение синтетических сложных эфиров

A mixture, obtained from the esterification process, is distilled to separate several fractions: the first fraction consists of the excess methanol and is distilled at atmospheric pressure, at a temperature that is gradually increased from 40 to 100°C. As soon as the excess methanol is extracted, a process of separating the second fraction begins by graduating the vacuum from 33 to 600 hPa, preferably from 50 to 150 hPa, and, as soon as a 600 hPa value is achieved, the increase in the temperature starts and continues from 80 to 90°C until the end of the separation of the second fraction consisting of esters of mono-carboxylic acids.

Известно, что термин вакуум имеет много значений, связанных так или иначе с условиями сильного разрежения или давлением значительно ниже атмосферного. Как лучше в данном аспекте перевести вакуум? Пониженное давление?Остаточное давление?
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