Institut Francais Du Pe'trole

Institut Fracnais Du Petrole

Lionel Asselineau

Paul Mikitenko

Alexandre Rojey

Christian R Busson

Ari Minkkinen

Jacques Alagy

Christian Streicher

Bernard Torck

Jean Gaillard

Massimo Zuliani

Michel Hellin

Jacques Leonard

Jean Alain Chodorge

Alain Convers

Jean Charles Viltard

Paul Mikitenlo

A process for the separation of oxygenated compounds, containing mainly methanol and possibly a minor amount of water and/or dimethyl ether, from a mixture of hydrocarbons containing 3 to 8 carbon atoms containing said oxygenated compounds. The mixture is distilled in a distillation zone (D). A gaseous distillate (line 2) is taken overhead which contains methanol, possibly water, possibly dimethyl ether, and hydrocarbons. The gaseous distillate is separated in a separator (B) and at least one organic liquid phase is recovered (line 6) and sent as a reflux to the head of distillation zone D. An aqueous liquid phase (line 5) may possibly be recovered, also a gaseous phase (line 4). A phase (line 8) is extracted as a side stream from the distillation zone and sent to a permeation zone (PV) comprising at least one membrane which is selectively permeable to methanol; a permeation step is carried out on said phase. At least one methanol-enriched permeate (line 14) is recovered downstream of the permeation zone, preferably as a vapor, and at least one residue (line 11) is recovered upstream which is optionally recycled to the distillation zone. The purified hydrocarbon mixture is extracted (line 16) from the bottom of the distillation column.

Combined distillation and permeation process for the separation of

Process for the production of tertiary ethers (MTBE, ETBE, TAME, ETAE) in which a hydrocarbon cut (1) containing four or five carbon atoms is reacted with methanol or ethanol (2, 3) in a reactor and recovering ethers (11) and a distillate (10) after distillation (C.sub.I). The distillate undergoes a first extractive distillation step in column (C.sub.11) in the presence of a solvent (27) which is selective towards olefinic hydrocarbons. A saturated hydrocarbon-rich overhead fraction (15) is recovered along with a bottom fraction (18) which is rich in olefins, solvent and alcohol. The olefins (20) are separated from the solvent and alcohol (24) in a second extractive distillation step (C.sub.III). The olefins are isomerised in a skeletal isomerisation reactor (5) and the isomerate is recycled (2) to reactor (6). The alcohol and solvent are separated in a stripping column (C.sub.IV). Alcohol (26) is recycled to the synthesis reactor (6) while the solvent (27) is recycled to C.sub.II. The temperature at the bottom of the second column (C.sub.III) can be reduced by addition of fresh (4) or recycled (34) alcohol.

Process comprising two extractive distillation steps for the production

A reactive distillation process which makes it possible, in the same enclosure, to carry out a catalytic reaction and isolate by distillation the sought product, in which the liquid phase containing the reagents passes from bottom to top through at least one catalyst bed, without the vapor phase of the distillation traversing said catalyst beds. These operating characteristics occur in a reactive distillation zone (C) including an alternation of distillation cells (D) having one or more trays (5) and reaction cells (R) containing the catalyst beds and designed in such a way that the liquid phase flowing from a distillation tray (5) flows above an overflow ( 7) through a downpipe (6) and approaches the base of the catalyst bed (8), traverses the latter in a downward flow and is then allowed to flow over a distillation tray (5) of the following distillation cell (D), so that the distillation vapor circulating from bottom to top through the distillation trays (5) does not traverse said reaction cells (R). Each reaction cell (R) is physically separated from the adjacent distillation cell or cells (D). The process can in particular be applied to the synthesis reactions of tertiary alkyl ethers by the addition of aliphatic monoalcohols (methanol, ethanol) on isoolefins (isobutene, isopentene).

Reactive distillation process and apparatus for carrying it out

For the separation of butenes and butanes by extractive distillation, a charge mainly containing butenes and butanes is contacted in an extractive distillation column under pressure with a first selective polar solvent, S1 (e.g., dimethyl formamide), the butanes being collected at the top. The solvent S1 containing the butenes and passing out at the bottom is mixed with a second solvent, S2, having a boiling point intermediate between that of butenes and that of the solvent S1, the mixture passing into a desorption column under pressure, where the butenes are collected at the top. The mixture of solvent S1 and S2 is separated in a purification column under atmospheric pressure, the solvent S2 passing out at the top is recycled to the desorption column, and the solvent S1 passing out at the bottom is recycled to the extractive distillation column.

Process for the separation of butenes and butanes by extractive

For the separation of butanes and butenes by extractive distillation, a charge mainly containing butanes and butenes is contacted in an extractive distillation column under pressure with a polar solvent (e.g., dimethyl formamide), the butanes being collected at the head. The solvent containing the butenes passes into a second column under pressure, where the butenes are partly desorbed and collected at the head. The solvent still containing butenes is purified in a third column under atmospheric pressure and the solvent-containing vapor distillate thereof is returned, after compression, to the lower part of the second column.

Process for the separation of butanes and butenes by extractive

For preparing at least one boric oxide in an anhydrous or hydrated form and of general formula B.sub.2 O.sub.3, xH.sub.2 O, in which x is a number from 0 to 3, a methyl borate hydrolyzate comprising boric oxide and methanol is introduced into a distillation column is introduced the product from, at least one compound (preferably a hydrocarbon such as, e.g., 2,3-dimethyl butane or 2-methyl pentane) forming a heteroazeotrope with methanol, said heteroazaeotrope having a boiling point below that of the azeotrope formed by methyl borate with methanol and at least one compound having a boiling point higher than that of methyl borate, said compound not forming an azeotrope with a boiling point below that of said heteroazeotrope and then at the head of the column said heteroazeotrope is recovered and at the bottom of the column a suspension containing at least one boric oxide. A description is also given of a process for the oxidation of at least one saturated hydrocarbon into a product incorporating the corresponding alcohol wherein oxidation is carried out with oxygen in the presence of a boric oxide with. The oxidation product is hydrolyzed into orthoboric acid and alcohol, which is recovered by separation from the organic phase. The aqueous phase containing the boric acid is fed into a methyl borate formation zone and the methyl borate is recovered in the form of its azeotrope with methanol. The recovery of the boric oxide from said azeotrope is performed in accordance with the aforementioned process, the recovered boric oxide being recycled to the oxidation stage.

Process for the preparation of boric oxide by hydrolysis of methyl

A C.sub.4 and/or C.sub.5 olefinic hydrocarbon cut, containing dimethyl ether and water as impurities, in a relative proportion of dimethyl ether to water of at most 5:1, is purified in a distillation zone where it is introduced at an intermediate level, distant from the top or from the bottom thereof by at least 3 theoretical plates, optionally with a stripping gas, and separated into a overhead fraction comprising an aqueous liquid phase and a hydrocarbon liquid phase at least partially recycled as reflux to the upper part of the distillation zone, and a bottom fraction formed of the purified C.sub.4 and/or C.sub.5 olefinic cut.

Process for purifying a C.sub.4 and/or C.sub.5 hydrocarbon cut

Process for dehydrating aliphatic alcohols admixed with water wherein the alcohols-water mixture is subjected to a first fractionation in the presence of a selective solvent, giving a vapor effluent containing dehydrated light alcohols and a liquid phase containing heavy alcohols, water and the selective solvent, said liquid phase being subjected to a second fractionation giving as vapor effluent an hetero-azeotropic mixture of water and heavy alcohols and, as liquid effluent, the selective solvent, which is fed back, said hetero-azeotropic mixture being condensed and separated into:

Process for producing dehydrated alcohols for use as component of a

Methyl tert.butyl ether is obtained by reacting an isobutene-containing C.sub.4 cut with methanol and distilling the reaction product at a superatmospheric pressure of 7-30 atm. abs. to recover a top fraction and a bottom fraction containing methyl tert.butyl ether. The isobutene conversion rate and the purity of the ether are increased by recycling a portion of the top fraction to the reaction zone.

Process for manufacturing and recovering methyl tert.butyl ether

Process for isolating methyl tert-butyl ether contained in the reaction product of methanol with a C.sub.4 hydrocarbon cut containing isobutene, comprising fractionating said reaction product by introducing it at an intermediate point of a distillation zone, recovering methyl tert-butyl ether at the bottom thereof and, at the top thereof, a mixture of C.sub.4 hydrocarbons with methanol which is washed with water and condensed and wherefrom is separated a condensed C.sub.4 hydrocarbon fraction, a portion of which is fed back as reflux to the top of the distillation zone and another portion discharged, and separating the remaining water-methanol mixture by distillation.

Process for isolating methyl tert-butyl ether from the reaction products

Process for producing and isolating methyl-tert-butyl ether (MTBE) comprising etherifying isobutene, contained in a C.sub.4 hydrocarbons mixture, with methanol in the presence of a recycle stream of C.sub.5 and/or C.sub.6 hydrocarbons, separating from the obtained reaction product, by fractionation, at least the major part of the unconverted C.sub.4 hydrocarbons, and discharging them, and fractionating the remaining product in two fractions, one of which contains an azeotrope of methanol with the C.sub.5 and/or C.sub.6 hydrocarbons and is recycled, the other fraction containing the purified MTBE.

Process for the preparation and isolation of methyl-tert-butyl ether

Process for separating benzene and/or toluene from mixtures thereof with saturated hydrocarbons, by extractive distillation using an aliphatic N-alkylamide as extraction solvent, comprising introducing in the distillation column, above the level of introduction of the extraction solvent, liquid water in an amount and under such conditions that said water is completely vaporized without substantially diluting the solvent, condensing the vapors discharged from the top of the column and dividing the resulting condensate into a phase of liquid saturated hydrocarbons, and a phase of water.

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Paris, France

Lionel Asselineau