The present disclosure provides a method for producing purified trans-1,2-difluoroethylene (HFO-1132(E)) and/or 1,1,2-trifluoroethylene (HFO-1123), comprising a distillation step of distilling composition 1 comprising difluoromethane (HFC-32) and HFO-1132(E) and/or HFO-1123 to obtain composition 2 in which HFC-32 is reduced from composition 1; and an extractive distillation step of bringing composition 2 into contact with an extraction solvent to obtain a composition comprising HFO-1132(E) and/or HFO-1123, in which HFC-32 is reduced from composition 2, composition 2 being an azeotropic composition or azeotrope-like composition comprising HFC-32 and HFO-1132(E) and/or HFO-1123.

The present disclosure provides a control method for a rectification and purification system of electronic-grade chlorine trifluoride. A rectification device of electronic-grade chlorine trifluoride includes a two-stage cryogenic rectification device including a low-boiling column and a high-boiling column. An extraction agent is arranged in the two-stage cryogenic rectification device for further dissociating associated molecules of hydrogen fluoride and chlorine trifluoride to meet the requirements of electronic-grade chlorine trifluoride. The reflux ratio parameter stability of a vapor-liquid (chlorine trifluoride-hydrogen fluoride) phase equilibrium system can be effectively improved by a column plate temperature control method, thus realizing wide dynamic smooth running under various working conditions. The column plate temperature control method can achieve an effective separation of chlorine trifluoride and various impurity components by deep rectification technology, yielding electronic-grade chlorine trifluoride through purification.

The present disclosure provides a control method for a rectification and purification system of electronic-grade chlorine trifluoride. A rectification device of electronic-grade chlorine trifluoride includes a two-stage cryogenic rectification device including a low-boiling column and a high-boiling column. An extraction agent is arranged in the two-stage cryogenic rectification device for further dissociating associated molecules of hydrogen fluoride and chlorine trifluoride to meet the requirements of electronic-grade chlorine trifluoride. The reflux ratio parameter stability of a vapor-liquid (chlorine trifluoride-hydrogen fluoride) phase equilibrium system can be effectively improved by a column plate temperature control method, thus realizing wide dynamic smooth running under various working conditions. The column plate temperature control method can achieve an effective separation of chlorine trifluoride and various impurity components by deep rectification technology, yielding electronic-grade chlorine trifluoride through purification.

This process relates to controlling acetal formation when removing acetaldehyde from a methanol carbonylation process using an extractive distillation column. Acetals may be formed by a secondary reaction of acetaldehyde and an alcohol (such as methanol). The process controls the formations to prevent excess acetal accumulation in the lower stream from the extractive distillation column.

This process relates to controlling acetal formation when removing acetaldehyde from a methanol carbonylation process using an extractive distillation column. Acetals may be formed by a secondary reaction of acetaldehyde and an alcohol (such as methanol). The process controls the formations to prevent excess acetal accumulation in the lower stream from the extractive distillation column.

A process for producing acetic acid is provided that is capable of lowering acetaldehyde mass composition in acetic acid. The process for producing acetic acid according to the present invention comprises at least one distillation step that satisfies the following operating conditions (i) temperature in a lower portion of the distillation column is not less than 40° C.; (ii) water mass composition in the lower stream is not less than 0.3 wt. %; or (iii) acetic acid mass composition in the lower stream on weight percentage basis is greater than the acetic acid mass composition in the first mixture; wherein the methanol mass composition in the first mixture is less than or equal to 2 wt. %.

A process for producing acetic acid is provided that is capable of lowering acetaldehyde mass composition in acetic acid. The process for producing acetic acid according to the present invention comprises at least one distillation step that satisfies the following operating conditions (i) temperature in a lower portion of the distillation column is not less than 40° C.; (ii) water mass composition in the lower stream is not less than 0.3 wt. %; or (iii) acetic acid mass composition in the lower stream on weight percentage basis is greater than the acetic acid mass composition in the first mixture; wherein the methanol mass composition in the first mixture is less than or equal to 2 wt. %.

The present invention provides a method for separating HFC-245cb and (E)-HFO-1234ze having close boiling points, i.e., boiling points with only 1° C. difference, by extractive distillation from a composition containing the HFC-245cb and the (E)-HFO-1234ze. More specifically, the present invention is a method for separating HFC-245cb and (E)-HFO-1234ze from a composition containing the HFC-245cb and the (E)-HFO-1234ze, the method comprising subjecting the composition to extractive distillation using at least one extractant selected from the group consisting of halogenated hydrocarbons, halogenated unsaturated hydrocarbons, nitriles, ketones, carbonates, alcohols, hydrocarbons, esters and ethers.

The present invention provides a method for separating HFC-245cb and (E)-HFO-1234ze having close boiling points, i.e., boiling points with only 1° C. difference, by extractive distillation from a composition containing the HFC-245cb and the (E)-HFO-1234ze. More specifically, the present invention is a method for separating HFC-245cb and (E)-HFO-1234ze from a composition containing the HFC-245cb and the (E)-HFO-1234ze, the method comprising subjecting the composition to extractive distillation using at least one extractant selected from the group consisting of halogenated hydrocarbons, halogenated unsaturated hydrocarbons, nitriles, ketones, carbonates, alcohols, hydrocarbons, esters and ethers.

The present invention provides a method for separating HFC-245cb and (E)-HFO-1234ze having close boiling points, i.e., boiling points with only 1° C. difference, by extractive distillation from a composition containing the HFC-245cb and the (E)-HFO-1234ze. More specifically, the present invention is a method for separating HFC-245cb and (E)-HFO-1234ze from a composition containing the HFC-245cb and the (E)-HFO-1234ze, the method comprising subjecting the composition to extractive distillation using at least one extractant selected from the group consisting of halogenated hydrocarbons, halogenated unsaturated hydrocarbons, nitriles, ketones, carbonates, alcohols, hydrocarbons, esters and ethers.