LU84805A1 - PROCESS FOR THE PREPARATION OF TERT.BUTYL-ALKYL ETHERS - Google Patents

Abstract

A process for synthesising t-butyl alkyl ethers is combined with a process for isomerising butene-1 and/or butene-2 in order to increase the ether yield. A C4 hydrocarbon feedstock (1) containing isobutene but free of butadiene is reacted (4) with an alkanol (6) and the ether product (5) is separated from residual hydrocarbons (7), (8); the latter are fractionated to separate saturated hydrocarbons (10), (14), from the butene-1 (12) and the butene-2 (15); the butene-1 and/or butene-2 are isomerised (16) to a product (2) containing isobutene which is recycled to reactor (4). <IMAGE>

Description

'..7. ·:} · ···' ·. . y: 7 the Minister - -Λ; r. jrnie and these Moi er Classes. born r - * rc. V ->. "> · - v ..... - · .......... irrvi -.- e ce 3a Intellectual Property L * ~; ----- ΓΤ7 .... .4M * luxury: ”: town, </;; Invention patent application I. ÎL quest SpA, corso .16, ..... I - Milan ............. ........................................... (i) rsprêssntSe per KM. FSEYLIX'C-UR trunst ï. & M.SYERS Err.ast, i ^ g.cons. & N propr.ind., 46 rua du Ct ~ 2tiera, Luxaxbourg, (2) acting as E.anà »tairas depositor ) this fcreiza may beil nine cant four-four-three ^ at ........ hours, at the Ministry of Economy and Middle Classes, in Luxembourg: 1. this request for obtaining a invention patent concerning: * ..... Preparation procedure ..... ù ^ tnars t & rt.butyl-alkvliaues w ............... (4) 2. la delegation of power, dated de dilaTI ................ .......... I April 22, 1583 3. description in language ....... ....... ÜF?. *. *?.! R___________________ of the invention in duplicate; 4. ........ 1 ............... drawing boards, in two copies; 5. left it nce of the fees paid to the Luxembourg Registration Office on April 28th, mil nsuf cant eighty-three declares (s) assuming responsibility for this declaration, that the inventor (s) is ( are): 1 ...... Srunô ce Xsgii2, via cisnondi 48, I - Milan 2 "P.-srso jÇc-ictto, via Sallinciona 10, ï - Milan revenàiqtie (nt) for the above patent application priority one (s) request (s) from (6) ..........................; v · 'c ............ .............. deposited® in (7) .............. . ± ζ1 ±?? ............................................ ..................................

on ..... twenty .. may irll rsuf o-ar.t ninety-six under no. (8) 21334k [62 '. '' '".............. Γ”' .'... 'I' '.... I. ZZIIIZZZin on behalf of .......... .SnÂîltprOgatti SpA .............. ............ ..................... ....... ...................................... ..... .......... {S) éJii (elect) for him / her and if designated, for his / her representative, in Luxembourg___________________ __________ 46 rua ^ Ci: r: i ère soIIicHeÇnt) the grant of a patent of invention for the object described and represented in the abovementioned appendices, - with postponement of this issue to ............. ®.i? ........... .................. months. (11) l1 one of the agents —®L Deposit Report

The above application for a patent for invention has been filed with the Ministry of the Economy and the Middle Classes, Service de la Propriéi ^^ etlet'Tiql] e in Luxembourg, on: (g - "2 d Pr. Minister έ hour "V of the Economy and Movennes Moves, June 1 ..... f ι -.1. ι ~ · ^" / ~ ____ under no. 21i64A / c2 _________________ /

PATENT

S NAMPROGETTI S.p.A. corso Venezia 16 I - Milan "Process for the preparation of tert.butylalkyl ethers i

Process of p ”·; ·]. .-î r a t. ·. , that is to say .Lut} '! -al Py] i 4aes.

The present invention relates to a process for preparing ether tert .butyl-al bylics.

More particularly, the present invention relates to a process for the preparation of tert-butyl ethyl ethers.

In the art, a large number of processes are known for preparing butyl alkyl ethers, consisting in reacting the isobutene contained in the streams of hydrocarbons of different origins and in particular in the streams originating from steam cracking, catalytic cracking or dehydrogenation of isobutane, with an alcohol, preferably methanol or ethanol, in the presence of an ion-exchange resin, of the acid type.

In this respect, reference can be made to the Italian patents 15 0 012 686, 1 012 687 and 1 012 690.

The known processes allow almost complete conversion of isobutene, but the other constituents remain practically unchanged, and therefore cannot be used as such directly as the constituents of petroleum.

The process according to the present invention allows the conversion of part of the constituents of the feedstock into hydrocarbons with 4 carbon atoms, other than isobutene, into tert.butylalkyl ethers at the same time as the isobutene initially contained in said feedstock.

The process according to the present invention comprises the following stages: 1) feeding the hydrocarbon feedstock either without butadiene or almost without butadiene to a section for synthesis of tertiary butyl alkyl ether, this section containing 30 a catalyst consisting of an ion exchange resin, of the acid type, preferably of the divinylbenzene-styrene sulfone type.

2) Reaction of the isobutene contained in the hydrocarbon feedstock at point 1) with an aliphatic alcohol supplied to said synthesis section, the molar ratio of alcohol to isobutene being between 0, 9 and 1.3, J- the reaction product being a tert.butyl-allcyl ether.

c ......-- / i 3d separation of 1 ’ether t c-r t. l · utyl - a j byl i that hydrocarbons by distillation either in the r.Sme reaction zone, or in a separate zone.

4) Fraction ionneir.ent of the residual hydrocarbon charge 5 in two or three stages at a temperature between 40 ° C and 150 ° C and under an absolute pressure between 4 bars and 26 bars, using 100 to 220 trays for separating the saturated hydrocarbons (butane and isobutane) from butene-1 and butene-2 10 5) Supply of butene-1 and / or butene-2 and saturated constituents not separated from 6tade 4 towards an isomerization stage in which the butene-1 and / or butene-2 are partially converted into isobutene to obtain, whatever the starting olefin or the starting mixture, a hydrocarbon fraction containing essentially butene-1, butene-2 and isobutene , in which the butene-1 / butene-2 molar ratio corresponds practically to the thermodynamic equilibrium, while the isobutene / linear butene molar ratio is between 0.6 and 0.3.

6) Separation of the hydrocarbon fraction containing butene-1, butene-2 and isobutene from heavy products. a word Food for the hydrocarbon fraction containing butene-1 f butene-2 and isobutene and, optionally, also from the part of the heavy and saturated constituents, to section 25 of synthesis of ether tert.butyl-albylique, either directly or after mixing with the hydrocarbon stream free or almost free of butadiene. The feedstock containing hydrocarbons, possibly 1 ement; also constituents in and C, -.

The feedstock normally comprises C ^ hydrocarbons, isobutane, isobutene, butene-1, n-butane, trans * butene-2, cis-butene-2 and 0 en hydrocarbons. The C- and Cc hydrocarbons are in small amounts, and the others may be in relative amounts which vary widely depending on their origins.

In order to obtain a constant molar ratio between butene-1, butene-2 and isobutene, the isomerization of butene-, 1 and / or butene-2 is carried out using a process such! than that described in the Italian patent & n ° 1 017 878. with a catalyst based on I have a J ne with silica, such as q „c- that described in the US patents n ° 4 Ü15 SS 9 and 4 Ü15 590.

It is interesting to note that the process according to the present invention makes it possible, not only, to obtain tertiary ether.

5 butyl-albyl ique possible harm 3 eiaent, equal to the goal c-ne-1 pure or otherwise butene-2, which can be used for applications other than those mentioned in the present description.

The process according to the present invention is therefore very universal, and it has been discovered that even large variations in the isobutene content of the stream fed to the synthesis section do not change the operating conditions of this synthesis.

The method according to the present invention is illustrated by the descriptive and non-limiting diagram indicated in the attached single figure.

In this diagram, (1) indicates the hydrocarbon feedstock free or practically free of butadiene, (2) the flow coming from the isomerization reactor (16) and which comprises butene-1, butene-2 and isobutene and a certain amount of saturated hydrocarbons, (3) is the total flow of (1) and (2), (4) is the unit of synthesis for tertiary ether. butyl-methyl (ETBM), (5) is the ETBM flow, (6) is the methanol flow supplied to the synthesis section, (7) is the fraction of hydrocarbons almost free of isobutene, (19) is an optional selective hydrogenation stage for the residual butadiene and any acetylenic compound, (8) is the flow supplied to the fractionation section for saturated hydrocarbons and olefins, (9) is the column for the separation of isobutane (10), (11) is the column for the separation of butene-1 (12), and (13; is the column for the separation of n-butane (14) from cis-and trans-butene-2 (15).

The stream (12) of butene-1 can be fed to the isomerization reactor (16) by the line (17), or it can be evacuated the necessary purity by the line (18). (20) represents the hydrogen flow.

Table 1 illustrates by way of nonlimiting example 4__ tii, iît * s coudât i i ') iS ί-λ] ·,!;: 5 t-ji t aies de ί ο neti ο η nent as well as the results telatlfs obtained by the method according to the present invention, with reference to the single figure, using the selective hydrogenation unit (19) and the flow of hyurogc-ne ς. f20) without recvcluding the butene (1) towards the isonization cone.

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Claims (4)

1. Process for the preparation of tertiary ethers. butyl-alkyli-ques starting from a feedstock of hydrocarbons possibly containing also constituents in C ~ 5 and C ^, which butadiene, was separated beforehand, process which consists in feeding the feedstock of C ^ hydrocarbons, free or almost free of butad i c-ne, to a synthesis section of tert.butylalkyl ethers containing a catalyst constituted by an ion-exchange resin, of the acid type, preferably of the divinylbenzene-styrene sulfone type, reacting the isobutene contained in the hydrocarbon feedstock with with an aliphatic alcohol in order to prepare a tert.butylalkyl ether, and in separating the tert.butylalkyl ether from the residual hydrocarbons, this process being characterized in that the residual hydrocarbons are subjected to fractionation in two or three stages in order to separate the saturated hydrocarbons from butene-1 and butene-2, and butene-1 and / or butene-2 s fed to an isomerization stage 20 where they are partially converted into isobutene to obtain a hydrocarbon fraction containing essentially butene-1, butene-2 and isobutene as well as heavy products, the hydrocarbon fraction essentially containing butene-1, butene-2 and isobutene and optionally the part of the heavy and saturated constituents being fed to the synthesis reaction of tert-butyl alkyl ethers. 2. Method according to claim 1, characterized in that butene-1, butene-2 and isobutene are present in the fraction of hydrocarbons originating from the isomerization stage in proportions such that the butene-1 / butene-2 molar ratio corresponds to thermodynamic equilibrium, while the isobutene / linear butene molar ratio is between 0.6 and 0.3. 3. Method according to claims 1 and 2, character-ized in that the hydrocarbon fraction from the isomerization stage of butene-1 and / or butene-2 is fed ii to the synthesis section after being mixed with the hydrocarbon flow in free or almost free of butadiene. f. 4. Method according to any one of the preceding claims, characterized in that the isomerization stage is carried out by feeding only the cis-and trans-butene-2. / i 4