Abstract: Demulsifiers containing an anionic surfactant selected from alkylsulfosuccinates, alkylsulfonates, alkylphosphonic acids, and their salts; a nonionic surfactant selected from ethylene oxide/propylene oxide copolymers, ethoxylated fatty acids of polyethylene glycol, terpene alkoxylates, and modified alkanolamides; or a combination of an anionic and a nonionic surfactant, and methods of use thereof in breaking emulsions.

Abstract: Disclosed is a method for preparing liquid fuel and chemical intermediates from biomass-derived oxygenated hydrocarbons. The method includes the steps of reacting in a single reactor an aqueous solution of a biomass-derived, water-soluble oxygenated hydrocarbon reactant, in the presence of a catalyst comprising a metal selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au, at a temperature, and a pressure, and for a time sufficient to yield a self-separating, three-phase product stream comprising a vapor phase, an organic phase containing linear and/or cyclic mono-oxygenated hydrocarbons, and an aqueous phase.

Abstract: The present inventions are (A) a solvent comprising at least one cycloalkyl alkyl ether (1) represented by the general formula: R1—O—R2 (wherein R1 is cyclopentyl or the like; and R2 is C1-10 alkyl or the like); (B) a method of preparations the ethers (1) characterized by reacting an alicyclic olefin with an alcohol in the presence of an acid ion-exchange resin having a water content of 5 wt % or less. The solvent is useful as cleaning solvent for electronic components, precision machinery components or the like, reaction solvent using various chemical reactions, extraction solvent for extracting objective organic substances, solvent or remover for electronic and electrical materials, and so on. The process enables industrially advantageous production of the objective cycloalkyl alkyl ethers (1).

Abstract: A catalytic reaction-rectification integrated process and a catalytic reaction-rectification integrated column (T-01), the specialized device of such process. The process comprises that the reactants are preheated and mixed with catalysts, and then fed into a jet agitation reaction section (6) located in the middle of the catalytic reaction-rectification integrated column (T-01) from a feeding inlet. The jet agitation reaction section (6) is a kettle-like reactor located in the middle of the catalytic reaction-rectification integrated column (T-01). After pressurized by a centrifugal pump (21), the reactant materials are admitted into a subsonic or transonic agitator (33) located within the reaction section (6). The reactant materials are ejected into the jet agitation reaction section (6) at high speed, to efficiently mix the solid and liquid phases in the reaction section (6) and to reinforce heat and mass transfer efficiency during the reaction.

Abstract: An enhanced method of producing ethers from iso-olefins and alcohols comprises at least one stage of separation of the excess alcohol by an ionic liquid. The ether-hydrocarbon-alcohol effluent treated in said separation stage by the ionic liquid comes from the reaction section and/or from a fractionating column. The separated and condensed alcohol is recycled in the process.

Abstract: This disclosure provides a method of preparing a crystalline molecular sieve comprising: (a) providing a reaction mixture comprising at least one source of ions of tetravalent element Y, at least one source of alkali metal hydroxide, water, optionally at least one seed crystal, and optionally at least one source of ions of trivalent element X, the reaction mixture having the following molar composition: Y:X2=2 to infinity, preferably from about 2 to about 1000, OH?:Y=0.001 to 2, preferably from 0.1 to 1, M+:Y=0.001 to 2, preferably from 0.

Abstract: Methods and catalysts for producing alcohols, ethers, and/or alkenes from alkanes are provided. More particularly, novel caged, or encapsulated, metal oxide catalysts and processes utilizing such catalysts to convert alkanes to alcohols and/or ethers and to convert alcohols and/or ethers to alkenes are provided.

Abstract: A process for producing a tertiary olefin and an aliphatic alcohol, which comprises adding an aliphatic alcohol to an alkyl tertiary-alkyl ether in advance, and then, decomposing the alkyl tertiary-alkyl ether. Examples of the aliphatic alcohol include methanol, ethanol and the like.

Abstract: Processes for preparing dibutyl ethers from 2-butanol using an ionic liquid.

Abstract: An enhanced ether production process from an olefinic cut containing at least one iso-olefin and from an alcohol comprises a stage of removal of the acetonitrile present in the hydrocarbon feed by liquid-liquid extraction, the extraction solvent being a non-aqueous ionic liquid of general formula Q+A?, wherein Q+ is an ammonium, phosphonium and/or sulfonium cation, and A? an anion likely to form a liquid salt with said cation. Advantageously, the method according to the invention generally allows the amount of water at the etherification reactor inlet to be divided by at least two and thus the purity of the ether produced to be improved.

Abstract: The present invention relates to the production of butenes and derivatives thereof from dry ethanol, optionally obtained from a fermentation broth. The butenes thus produced find use as intermediates for the production of polyethylenes and other materials.

Abstract: The present invention relates to the production of butenes and derivatives thereof from aqueous ethanol, optionally obtained from a fermentation broth. The butenes thus produced find use as intermediates for the production of polyethylenes and for the production of other known, useful materials.

Abstract: A process for producing ethers by reacting alcohols and olefins in successive catalytic stages is disclosed. The process includes alternating catalytic reaction stages and separation stages.

Abstract: The present invention relates to the production of butenes and derivatives thereof from aqueous ethanol, optionally obtained from a fermentation broth. The butenes thus produced find use as intermediates for the production of polyethylenes and for the production of other known, useful materials.

Abstract: The invention relates to processes for the etherification of olefins with alcohols. According to one aspect, a heterogeneous etherification catalyst is used under conditions that permit limiting the contact time between the desired product and the catalyst, thereby mitigation reverse reactions. According to a second aspect, a recycling process is used that significantly increases the yield of desired product.

Abstract: The present invention relates to a method for catalytic deoxygenation of process fluids of olefin dimerization processes. According to the invention at least one process fluid containing oxygenates is brought into contact with a deoxygenation catalyst at, at least one location in a column or connected to a column. The present invention relates also to a process for dimerization of olefins, wherein at least part of olefin feed is dimerized in at least one dimerization reaction zone to produce a first product stream comprising oxygenates, and separating in a distillation zone, comprising one or more distillation columns, the first product stream into a second product stream and a third product stream and at, at least one location of the distillation column or a vessel connected to the distillation column is located a deoxygenation catalyst for decomposing oxygenates.

Abstract: Process for the production of alkyl ethers by the etherification of isobutene, contained in C4-C5 hydrocarbon streams, with linear alcohol, in the presence of acid catalysts, comprising the following essential steps: a) feeding the isobutene contained in C4-C5 hydrocarbon cuts, together with one or more streams containing linear alcohol, to a first reaction step; b) sending the stream leaving the first reaction step to a first distillation area, separating a light stream from a heavy stream containing the desired ether; c) feeding the light stream separated in the first distillation area, together with one or more streams containing linear alcohol, to a second reaction step; d) sending the stream leaving the second reaction step to a second distillation area separating a light stream from a heavy stream containing ether, C4 hydrocarbons and alcohol which is recycled to the first distillation area; e) sending the light stream in the second distillation area to a recovery section of the linear alcohol contained

Abstract: Demulsifiers containing an anionic surfactant selected from alkylsulfosuccinates, alkylsulfonates, alkylphosphonic acids, and their salts; a nonionic surfactant selected from ethylene oxide/propylene oxide copolymers, ethoxylated fatty acids of polyethylene glycol, terpene alkoxylates, and modified alkanolamides; or a combination of an anionic and a nonionic surfactant, and methods of use thereof in breaking emulsions.

Abstract: A process for the production of tertiary ethers, including: feeding a hydrocarbon stream comprising isoolefins and propionitrile to a distillation column reactor system containing at least one etherification reaction zone; feeding a C2 to C6 monoalcohol or mixture thereof to the distillation column reactor; concurrently in the distillation column reactor system: reacting a portion of the isoolefins with a portion of the alcohols to form a tertiary ether; and separating the tertiary ether from unreacted isoolefins; withdrawing the tertiary ether and propionitrile from the distillation column reactor system as a bottoms; withdrawing the unreacted isoolefins from the distillation column reactor system as an overheads; and operating the distillation column reactor system such that the etherification reaction zone is substantially free of propionitrile.

Abstract: A process for the production of tertiary ethers, including: feeding a hydrocarbon stream comprising isoolefins and propionitrile to a distillation column reactor system containing at least one etherification reaction zone; feeding a C2 to C6 monoalcohol or mixture thereof to the distillation column reactor; concurrently in the distillation column reactor system: reacting a portion of the isoolefins with a portion of the alcohols to form a tertiary ether; and separating the tertiary ether from unreacted isoolefins; withdrawing the tertiary ether and propionitrile from the distillation column reactor system as a bottoms; withdrawing the unreacted isoolefins from the distillation column reactor system as an overheads; and operating the distillation column reactor system such that the etherification reaction zone is substantially free of propionitrile.

Abstract: The invention relates to a process for preparing butene oligomers and tert-butyl ethers from C4 hydrocarbon streams, by converting the isobutene to butene oligomers and tert-butyl ethers and removing them from the C4 streams.

Abstract: A process for preparing ethyl tert-butyl ether (ETBE) using low-water ethanol obtained by membrane dewatering at least two streams of relatively water-rich ethanol that have a different water content. by dewatering at membranes.

Abstract: The present invention relates to a catalytic process for making butenes using a reactant comprising 2-butanol and water. The butenes so produced may be converted to isoalkanes, alkyl-substituted aromatics, isooctanes, isooctanols and ethers, which are useful as transportation fuels.

Abstract: A process for producing alkyl ethers, by etherification of tertiary C4-7 olefins with an alkanol, comprising carrying out the etherification in reactor train system primarily configured for dimerization of isoolefins. In the etherification, the ratio of alkanol-to-olefin is 0.5 to 2, calculated from the amount of tertiary C4-7 olefins of the fresh feedstock. The invention makes it possible to change the product of the process from dimer to ether and vice versa merely by adjusting specific flows within the process. The present kind of process is therefore readily adaptable to fluctuating market demands for various gasoline octane-boosters (isooctane or MTBE).

Abstract: An allyl-containing compound represented by following Formula (3): wherein R2, R3, R4, R5 and R6 may be the same as or different from one another and each represent hydrogen atom or an organic group; R7 represents an organic group; and Y represents oxygen atom or sulfur atom, is produced by reacting an allyl ester compound represented by following Formula (1): wherein R1 represents hydrogen atom or an organic group; and R2, R3, R4, R5 and R6 are as defined above, with a compound represented by following Formula (2): R7—Y—H??(2) wherein R7 is an organic group; and Y is as defined above, in the presence of at least one transition element compound.

Abstract: The invention relates to a process for preparing methyl tert-butyl ether (MTBE) in qualities which are suitable for organic syntheses and for use as a specialty solvent from MTBE in fuel quality.

Abstract: A method for producing a fluoroalkyl ether, which comprises reacting a fluoroalkyl alcohol with a fluorinated olefin in the presence of a solvent and a catalyst, wherein the fluoroalkyl alcohol and the fluorinated olefin are continuously supplied into a reactor, a reaction product containing the fluoroalkyl ether is continuously withdrawn from the reactor, and the reaction is carried out while the concentration of the fluoroalkyl alcohol present in the reactor is maintained to be at most 7 mass % based on the total organic component present in the reactor. According to the present invention, a fluoroalkyl ether having a high purity can be produced in an industrial scale and at a high reaction rate.

Abstract: A process for the etherification of C4, C5 and/or C6 tertiary olefins in a hydrocarbon feed with at least one C1 to C6 alcohol, preferably C1–C4 alcohols in a distillation column reactor, preferably where C4's and C5's ethers are co-produced, in which the amount of alcohol employed in the etherification is below that which will produce an azeotrope with hydrocarbons in the overheads from the distillation column reactor. The azeotrope results from the presence of unreacted alcohol in the reaction system in the distillation column reactor. The amount of alcohol is less than the stoichiometric amount, preferably less than 90%, more preferably 10 to 80%, of the stoichiometric amount and the overheads contain less than a stoichiometric of alcohol.

Abstract: Disclosed is a process for removing DME from a stream containing C4 olefins. The process includes providing a first stream comprising C4 olefins, C5+ hydrocarbons, DME, and methanol. The first stream is separated into a second stream comprising the C4 olefins and the DME and a third stream comprising the C5+ hydrocarbons and the methanol. The second stream is directed to a DME absorption unit, wherein the second stream contacts water under conditions effective to separate the C4 olefins from the DME. Also disclosed is a process including contacting the first stream with water in a methanol removal unit under conditions effective to separate remove the methanol therefrom; distilling the methanol-depleted stream to remove C5+ hydrocarbon components, and contacting the stream with water in a DME removal unit under conditions effective to form an overhead stream comprising the C4 olefins and a bottoms stream comprising the DME.

Abstract: A process for reacting a first component with itself or a second component to produce a third component in which a first material comprising a first component or said first component and a second component is fed to divided wall column having a catalytic distillation structure in at least one of the separate vertical sections of the divided wall column where concurrently: (1) a first component alone or with a second component is contacted with a catalytic distillation structure in a distillation reaction zone thereby catalytically reacting at least a portion of the first component with itself or with the second component to form a product and (2) a first mixture comprising the first component and the product or the first component, the second component and the product; and withdrawing the product from the distillation column reactor; while within the column concurrently with the catalytic reaction and fractionation a second mixture is fractionated, which contains the first component and the product or first a

Abstract: A process for reacting a first component with itself or a second component to produce a third component in which a first material comprising a first component or said first component and a second component is fed to divided wall column having a catalytic distillation structure in at least one of the separate vertical sections of the divided wall column where concurrently: (1) a first component alone or with a second component is contacted with a catalytic distillation structure in a distillation reaction zone thereby catalytically reacting at least a portion of the first component with itself or with the second component to form a product and (2) a first mixture comprising the first component and the product or the first component, the second component and the product; and withdrawing the product from the distillation column reactor; while within the column concurrently with the catalytic reaction and fractionation a second mixture is fractionated, which contains the first component and the product or first a

Abstract: The present invention relates to purification of an MTBE process stream by contact in the liquid phase with a large pore zeolite such as 13X or Zeolite Y.

Abstract: A process for reacting a first component with itself or a second component to produce a third component in which a first material comprising a first component or said first component and a second component is fed to divided wall column having a catalytic distillation structure in at least one of the separate vertical sections of the divided wall column where concurrently: (1) a first component alone or with a second component is contacted with a catalytic distillation structure in a distillation reaction zone thereby catalytically reacting at least a portion of the first component with itself or with the second component to form a product and (2) a first mixture comprising the first component and the product or the first component, the second component and the product; and withdrawing the product from the distillation column reactor; while within the column concurrently with the catalytic reaction and fractionation a second mixture is fractionated, which contains the first component and the product or first a

Abstract: Olefins and alcohols present in Fischer-Tropsch light naphthas are converted to dialkyl ethers of the formula: R—O—R′ where R and R′ are each primarily non-tertiary alkyl groups of more than four carbon atoms, via hydration of the olefins to alcohols followed by dehydration of the alcohols. Ethers may also form by direct reaction of olefins and alcohols. The ethers are separated from the remaining paraffins in the naphtha by distillation and added in an amount of 1-25 wt. % to paraffinic mid-distillate fuel components obtained by hydrotreating a Fischer-Tropsch product. The properties of the distillate fuel components such as lubricity and seal swell are improved by the dialkyl ethers. The removal of olefins and alcohols from the naphthas reduces refining and lead to a more salable product.

Abstract: The invention describes a process for the preparation of novel surfactant alcohols and surfactant alcohol ethers by derivatization of olefins having from about 10 to 20 carbon atoms or of mixtures of such olefins to give alkanols, and optional subsequent alkoxylation, which comprises subjecting a C4-olefin mixture to metathesis, dimerizing the resulting olefins, and then derivatizing them to give surfactant alcohols, and optionally alkoxylating said alcohols. The olefin mixture obtained in the dimerization has a high proportion of branched components and less than 10% by weight of compounds which contain a vinylidene group. The invention further describes the use of the surfactant alcohols and surfactant alcohol ethers to give surfactants by glycosylation or polyglycosylation, sulfation or phosphation.

Abstract: Process for carrying out a reactive distillation in the presence of a heterogeneous catalyst which is suspended as disperse phase in the liquid, wherein part of the catalyst-containing suspension is continuously discharged from the column and is treated in a work-up stage and at least part of the work-up catalyst is returned to the column.

Abstract: The present invention provides a process, which includes: contacting at least one C4-hydrocarbon stream which includes isobutene with methanol over at least one acid catalyst and preparing methyl tert-butyl ether (MTBE) and a substantially isobutene-free C4-hydrocarbon mixture; wherein in a first stage in one or more first reactors, the isobutene reacts with the methanol over an acid catalyst to form an equilibrium mixture which includes MTBE, remaining isobutene and methanol; the equilibrium mixture is fed to a second stage which includes a reactive distillation column; and in the reactive distillation column, the remaining isobutene reacts with methanol over an acid ion exchange resin to form MTBE; wherein the reactive distillation column is operated at a pressure ranging from 3 to 15 bar abs., a reaction zone temperature ranging from 55° C. to 75° C., and a reflux ratio of less than 1.

Abstract: A process for the production of tertiary ethers from the reaction of isoolefins with lower alcohols, such as methanol, uses two distillation column reactors in series to maximize conversion, especially for isopentenes and isohexenes. The second distillation column reactor may be concurrently used as a C5 polishing reactor and a reactor for producing MTBE or ETBE from isobutene, for example.

Abstract: A process for producing an ether amine (3), which comprises reacting a primary or secondary alcohol (1), ROH, with acrylonitrile in an amount of 0.8 to 1.2 equivalents of the alcohol (1) in the presence of an alkali metal hydroxide in an amount of not less than 0.01 part by weight, but less than 0.05 part by weight per 100 parts by weight of the alcohol (1) to obtain an alkyloxypropionitrile (2), and then adding water to the reaction system without removing the alkali metal hydroxide therefrom and effecting hydrogenation using a hydrogenation catalyst: ROH(1)+CH2=CHCN→ROCH2CH2CN(2)→ROCH2CH2CH2NH2(3) wherein R denotes a linear or branched alkyl or alkenyl group having 6 to 24 carbon atoms.

Abstract: This invention concerns an improved and novel catalyst for preparing methyl tertiary butyl ether (MTBE). This invention is advantageous in that the reaction of methanol and isobutene takes place such that the catalysts exhibit levels of isobutene conversion as high as 98%, and the MTBE selectivity reaches as high as 98%. The improved catalysts comprises of a crystalline aluminosilicate zeolites, particularly MFI-type zeolites which has been treated with aluminum fluoride in the ratio 1 gram to 10 grams of zeolite with 0.5 gram to 5 grams of aluminum fluoride. A specific application of this improved and novel catalyst is reacting methanol and isobutene in a molar amount of about 0.1 mole to 10 moles of methanol per mole of isobutene, in the presence of said catalyst in a batch reactor, at about 70° C. to about 100° C., and a pressure of about 1 bar to 33 bar, to obtain MTBE product.

Abstract: The present invention concerns a process for the etherification of olefins. According to the process, an olefin or a mixture of olefins is reacted with an alcohol or a mixture of alcohols in the presence of a catalyst. According to the invention, a catalyst is used which comprises a grafted polymer fiber, there being functional groups attached to the grafted polymer fiber. By means of the invention it is possible to speed up the etherification process of, in particular, heavier ethers.

Abstract: The invention relates to a process for preparing at least one aliphatic monoalcohol, generally in excess, and at least one olefin. The process is performed in a distillation and reaction device having a reaction section and a distillation-reaction section. The distillation-reaction section has a distillation zone with at least one means for circulation of the effluent from the reaction section to the distillation zone. Effluent from the reaction section is circulated to the distillation zone. The distillation-reaction section also has at least one distillation-reaction zone having at least one catalyst bed. The distillation-reaction zone is distinct from the distillation zone and provides at least partly the reflux of the distillation zone. The distillation-reaction section can also have at least one complementary reaction zone containing at least one catalyst bed.

Abstract: The present invention provides a process for producing a (poly)alkylene glycol monoalkyl ether with high selectivity and high yield. In this process, the (poly)alkylene glycol monoalkyl ether is produced by reacting an olefin and a (poly)alkylene glycol in the presence of a catalyst, wherein: 1) a crystalline metallosilicate is used as the catalyst, and at least a portion of the used catalyst is regenerated, and the regenerated catalyst is recycled as the catalyst for the reaction; or 2) the reaction between the olefin and the (poly)alkylene glycol is carried out in the presence of either or both of a (poly)alkylene glycol dialkyl ether and an alcohol.

Abstract: The invention relates to a process for preparing tertiary alkyl ethers, in particular MTBE, ETBE or mixtures of these ethers with heavier ethers. According to the process the feedstock containing hydrocarbons is fed to a catalytic distillation reactor system, in which the isoolefines, in particular the C4 to C7 isoolefines, of the feed are reacted with an alkanol in the presence of a cation exchange resin in order to produce tertiary alkyl ether products. The reaction product containing the ethers is removed from the distillation system as the bottoms product and, if necessary, it is subjected to an additional treatment for producing a gasoline component. The unreacted alkanol is removed as the overhead product of the distillation.

Abstract: A process for isolating isobutene from a hydrocarbon mixture by a) combining the C4-hydrocarbon mixture with a primary C3- or C4-alkanol; b) reacting the isobutene in the C4-hydrocarbon mixture with the primary C3- or C4-alkanol in the presence of a heterogeneous catalyst to give the corresponding tertiary ether of isobutene, c) separating the resultant reaction mixture into the relatively low-boiling, unetherified C4-hydrocarbons and the relatively higher-boiling tertiary ether of isobutene with the aid of a distillation column, where the C4-hydrocarbons are taken off at the top, and the tertiary ether of isobutene obtained at the bottom is transferred into a reactor, d) cleaving this ether into isobutene and the corresponding primary C3- or C4-alkanol, e) distilling this mixture from d) in a further distillation column, and taking off the isobutene as the top product, which comprises carrying out step a) in a zone (4C) containing reactive internals and containing the catalyst for carrying out step b)

Abstract: A higher secondary alcohol alkoxylate compound composition represented by the general formula (1): [wherein R1 and R2 represent an alkyl group provided that the total number of carbon atoms of R1 and R2 is in the range of 7 to 29 and the number of carbon atom of R2 is not less than that of R1 (the number of carbon atom of R1<the number of carbon atom of R2), A represents a lower alkylene group, n represents a numeral in the range of 1 to 50 on the average; providing that when n is not less than 2, the number of species of oxyalkylene group represented by AO may be either one or two or more, and that when the oxyalkyl groups have two or more species, all the oxyalkylene groups are present in the average of n, and B represents a hydrogen atom or SO3M (wherein M represents an alkali metal atom, an alkaline earth metal atom, an ammonium group or a substituted ammonium group)], wherein the composition comprises 30 to 90 mol % of the higher secondary alcohol alkoxylate compound (X) ha

Abstract: A process for oligomerization of C4 and C5 isoolefins or the etherification thereof with C1 to C6 alcohols wherein the reactants are contacted first in a partial liquid phase reactor (boiling point reactor) with a fixed bed acid cation exchange resin catalyst at an LHSV of 5 to 20, pressure of 0 to 400 psig and temperature of 120 to 300° F., at a pressure to maintain the reaction mixture at its boiling point whereby at least a portion but less than all of the reaction mixture is vaporized and the entire reaction stream is directed to a catalytic distillation column reactor for further reaction of the reactants, where the improvement is having a decoupling drum between the boiling point reactor and the catalytic distillation column reactor. The addition of a decoupler drum allows the reactors to operate at a pressure independent of each other.

Abstract: Described is a process for preparing substituted butenes of the formula I and/or II, where the radical R is unsubstituted or mono- or di-C1-C10-alkoxy-substituted or mono- or dihydroxy-substituted C2-C20-alkyl or alkenyl or is C6-C10-aryl, C7-C11-aralkyl or methyl by reacting 1,3-butadiene with an alcohol of the formula ROH in which R is as defined in the presence of an acidic particulate catalyst insoluble in the reaction medium, which involves contacting the butadiene, the alcohol and the catalyst in a fluidized bed reactor which is flow-approached from below and is operated at above the loosening point.

Abstract: A process for eliminating at least pollutants including polar compounds present in a first fluid, with said first fluid sent to a subsequent treatment, e.g., an etherification process: a) the first fluid containing pollutants is contacted with an auxiliary fluid such as a vapor phase, under operating conditions that are selected so as to obtain, at the end of this first stage, said first fluid that is purified and freed of, for the most part, pollutants, and a vapor phase that is loaded with pollutants, said vapor phase being produced during one phase of the process, and b) at least a portion of said first purified fluid is recycled to a subsequent treatment stage.

Abstract: A process for preparing ethers includes the steps of: providing a feedstock containing iso-olefins selected from the group consisting of C5 iso-olefins, C6 iso-olefins and mixtures thereof; mixing the feedstock with alkyl alcohol so as to provide a reaction feedstock, feeding the reaction feedstock to a reactor zone in the presence of a first etherification catalyst whereby the alkyl alcohol reacts with the iso-olefins to form alkyl-tert-alkyl ethers so as to provide an intermediate feedstock containing the ethers and unreacted iso-olefins and alkyl alcohol; feeding the intermediate feedstock to a catalytic distillation column having a second etherification catalyst defining a catalytic zone; mixing additional alkyl alcohol to the intermediate feedstock so as to form azeotropes of the alkyl alcohol with the unreacted iso-olefins without forming azeotropes of the alkyl alcohol with the ethers whereby the catalytic zone is substantially free of the ethers and the unreacted iso-olefins react with said alkyl alc