The selective dimerization of isoolefins, such as isobutene or isopentane, or mixtures thereof, may be conducted in a system including a series of fixed bed reactors and a catalytic distillation reactor. The system may provide for conveyance of the fixed bed reactor effluents, without componential separation, to a downstream reactor. It has been found that a high selectivity to the dimer may be achieved even though intermediate separation of the desired product from unreacted components between reactors is not performed. Further, embodiments provide for use of a divided wall column for recovery of a high purity dimer product, reducing unit piece count and plot size.

Embodiments relate to a continuous process for the production of hydroxyethylpiperazine that includes feeding neat piperazine, recycled piperazine, and ethylene oxide to a reactor to form crude hydroxyethylpiperazine, in which the reactor is a continuous stirred tank reactor or a plug flow reactor. The process further includes continuously feeding the crude hydroxyethylpiperazine from the reactor to a distillation system that includes at least one distillation column, the distillation system produces at least a recycled piperazine stream and a hydroxyethylpiperazine stream, the recycled piperazine stream includes the recycled piperazine that is fed to the reactor to form the crude hydroxyethylpiperazine, and the hydroxyethylpiperazine stream includes at least 60 wt % of hydroxyethylpiperazine based on a total weight of the hydroxyethylpiperazine stream.

A process for the selective dimerization and etherification of isoolefins, including feeding a mixed C4 stream and an oxygenate stream to a first fixed bed reactor containing a first catalyst, producing a first reactor effluent comprising dimers of the isoolefin, unreacted C4s, and unreacted oxygenates. Feeding the first reactor effluent directly to a second fixed bed reactor containing a second catalyst, producing a second reactor effluent containing dimers of the isoolefin, unreacted C4s, and unreacted oxygenates. Feeding the second reactor effluent to a catalytic distillation reactor system containing a third catalyst. Concurrently in the catalyst distillation reactor system reacting unreacted C4s in the presence of the third catalyst to form additional dimers of the isoolefin and/or ethers, and separating the dimers of the isoolefins from unreacted oxygenates and unreacted C4s.

A production process of acetic acid according to the present invention inhibits concentration of hydrogen iodide and improves a liquid-liquid separation of an overhead from a distillation column. Acetic acid is produced by distilling a mixture containing hydrogen iodide, water, acetic acid and methyl acetate in a first distillation column (3) to form an overhead and a side cut stream or bottom stream containing acetic acid, cooling and condensing the overhead in a condenser (C3) to form separated upper and lower phases in a decanter (4). According to this process, a zone having a high water concentration is formed in the distillation column above the feed position of the mixture by feeding a mixture having a water concentration of not less than an effective amount to not more than 5% by weight (e.g., 0.5 to 4.5% by weight) and a methyl acetate concentration of 0.5 to 9% by weight (e.g., 0.5 to 8% by weight) as the mixture to the distillation column and distilling the mixture. In the zone having a high water concentration, hydrogen iodide is allowed to react with methyl acetate to produce methyl iodide and acetic acid.

A method for forming poly(dimethoxymethane) includes a step of separating a formaldehyde-containing blend into a first bottom stream and a first top stream. The first formaldehyde-containing blend includes methanol, formaldehyde, and water while the first bottom stream includes water. The first top stream includes dimethoxymethane that is produced from the reaction between methanol and formaldehyde. The first top stream is separated into a second bottom stream and a second top stream. The second bottom stream includes poly(dimethoxymethane) while the second top stream includes dimethoxymethane, methanol, and ethanol. The second top stream is separated into a third bottom stream and a third top stream. Third bottom stream includes methanol and ethanol while the third top stream includes dimethoxymethane. The third top steam can be recycled to form additional poly(dimethoxymethane). A system that implements the method is also provided.

Disclosed herein is a method for assisting a thermally-induced change to a nano-sized solute or dispersed-phase in a liquid. The method comprises the step of passing gas bubbles through the liquid, the gas in the gas bubbles having a temperature higher than the bulk temperature of the liquid.

Disclosed is a method for separating, with a multi-stage distillation column, a mixture containing an active hydrogen-containing compound (A) and a compound (B) that reversibly reacts with the active hydrogen containing compound (A), the method comprising distillation-separating the active hydrogen-containing compound (A) and the compound (B) with the multi-stage distillation column in the presence of an intermediate-boiling-point inactive compound (C) that has a normal boiling point between a normal boiling point of the active hydrogen-containing compound (A) and a normal boiling point of the compound (B) and is chemically inactive for both of the (A) and the compound (B).

A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

The present invention relates to a process for treating, by reactive distillation, an olefinic feedstock comprising linear olefins containing n carbon atoms, and branched olefins, the branched olefins comprising tertiary branched olefins, for example a mixture of n-butenes and of tertiary branched olefins comprising isobutene, so as to produce an olefinic effluent with a mass content of tertiary branched olefin of less than or equal to 3% by weight and a heavy hydrocarbon effluent, said process comprising the feeding of a reactive distillation section with said olefinic feedstock and with an alcohol feedstock comprising a primary alcohol, said reactive distillation section comprising a column composed at least of an upper reflux zone into which is introduced said alcohol feedstock, comprising, for example, ethanol, an intermediate reaction zone comprising at least 6 reactive doublets, and a lower fractionation zone at the level of which said section is fed with said olefinic feedstock, said reactive distillation section being operated at a relative pressure of between 0.3 and 0.5 MPa, a column head temperature of between 40° C. and 60° C., with a reflux ratio of between 1.8 and 2.2.

The present disclosure relates to a heat exchange system which is capable of saving energy consumed in a whole process by exchanging heat of different streams from each other, included in a continuous preparation system of a diester-based composition.