DE3318301A1 - METHOD FOR PRODUCING TERT.-BUTYL ALKYL ETHERS - Google Patents

Description

Description

Process for the preparation of tert -butyl-alkyl ethers

The invention relates to a process for the production of tert-butyl alkyl ethers, in particular for Production of tert-butyl methyl ether.

There are numerous processes for making tert-5 Butyl alkyl ethers, which are based on isobutene, which may be different in hydrocarbon streams Origin and in particular that from a steam cracking plant or plant for catalytic cracking * The stream obtained is contained with an alcohol, preferably methanol or ethanol in the presence of an acidic one Ion exchange resin is implemented. Please refer to IT patents 1 012 686, 1 012 687 and 1 012 690 referenced.

The known methods allow an almost full-15 constant isobutene conversion; but the other components remain practically unchanged and can therefore cannot be used immediately.

* or plant for the dehydration of isobutane

lA-57 222

The method according to the invention enables the conversion some of the components of the C. hydrocarbon mixtures used as starting material that are not Isobutene are, in tert-butyl alkyl ether, together with the isobutene originally contained in the feed stream.

The method according to the invention consists of the following Levels together:

1.) The C. hydrocarbon feed stream, which is either is free or essentially free of butadiene, is used in a unit for the synthesis of tert-butyl alkyl ethers out, this synthesis unit is filled with a catalyst made of an acidic ion exchange resin consists, preferably a sulfonated one

15 divinylbenzene-styrene resin.

2.) The in the (under point 1.) named) C. hydrocarbon feed stream contained isobutene is fed into the synthesis unit with an aliphatic Reacted alcohol, wherein the molar ratio of alcohol to isobutene is 0.9 to 1.3 and the reaction product is a tert-butyl alkyl ether. 3.) The tert-butyl alkyl ether is derived from the C. hydrocarbons separated by distillation, either in the same reaction zone or in a separate one

2 5 zone.

4.) The remainder of the C. Hydrocarbon streams is fractionally distilled in two or three stages at a temperature between 50 and 130 ⁰ C and at a pressure of 4 to 26 bar using 100 to 220 trays to give the saturated hydrocarbons (butane and isobutane) to be separated from butene-1 and butene-2.

IA-57 222

5. The butene-1 and / or butene-2 and the not separated Saturated components of stage 4.) are fed into an isomerization stage in which the Butene-1 and / or butene-2 are partially rearranged into isobutene, so that one is independent of the starting material used olefin or mixture receives a hydrocarbon fraction which is essentially consists of 1-butene, 2-butene and isobutene, the 1-butene / 2-butene molar ratio being practically the thermodynamic Equilibrium corresponds, while the molar ratio isobutene / linear butenes in the range from 0.3 to 0.6 is located.

6.) The hydrocarbon fraction containing butene-1, butene-2 and isobutene according to point 8.) is from the

15 heavy products separated.

7.) The hydrocarbon fraction, the butene-1, butene-2 and isobutene and optionally part of the heavy / products, is in the synthesis unit for tert "-butyl alkyl ether" fed, either directly or after mixing with the C. hydrocarbon stream, which is free or essentially free of butadiene. The C. hydrocarbon used as the starting material electricity may also contain C, - and C ,. Components.

The C. starting mixture usually comprises C 1-4 hydrocarbons, isobutane, isobutene, butene-1, n-butane ₍ trans-butene-2, cis-butene-2 and C 1-4 hydrocarbons. The C ₃ and C hydrocarbons are present in small amounts; the proportions of the other components can vary within wide limits, depending on the origin of the mixture.

/ * and saturated

IA-57 222 - St -

In order to maintain a constant molar ratio between butene-], butene-2 and isobutene is obtained isomerization carried out using a method as described in IT-PS 1 017 878, using a catalyst based on silica treated alumina, as in the US patents 4,013,589 and 4,013,590.

It is interesting to note that the procedure according to the present invention not only the production of pure tert-butyl alkyl ether but optionally also enables pure butene-1 or butene-2 to be obtained for purposes other than those described here can be used.

The method according to the invention is therefore very adaptable and it has been found that even significant Changes in the isobutene content of the hydrocarbon stream fed into the synthesis unit or zone will not change the working conditions for this synthesis.

The method according to the invention is explained in more detail below with reference to the accompanying drawing.

In this 1 means the C. hydrocarbon starting mixture, which is free or practically free of butadiene, 2 the hydrocarbon stream from the isomerization reactor 13, 1-butene, 2-butene and isobutene and a certain amount of saturated hydrocarbons contains; 3 the combined streams 1 and 2; 4 the synthesis unit for the tert-butyl methyl ether (MTBE); 5 den

»« Λ · «A ti

* «Ss» * ■ * (t ♦ A

-fr ff * ι »4 Φ Φ Φ «« * Mire »β« β

IA-57 222 - S -

MTBE product stream; 6 the methanol stream going into the synthesis unit is fed in; 7 the C. hydrocarbon fraction, which is practically free from isobutene; 19 a possibly provided zone or unit for selective hydrogenation of residual butadiene and any acetylenic compounds present, 8 the hydrocarbon stream flowing into the section for fractional distillation for the recovery of saturated Hydrocarbons and olefins are fed; 9 the distillation column for the separation of Isobutane 10; 11 the distillation column for the separation of butene-1 12; and 13 the distillation column for the separation of n-butane 14 from stream 15 from cis- and trans-butene-2.

The butene-1 stream 12 can via line 17 to the isomerization reactor 16 or are discharged via line 18 with the required purity. 20 means the hydrogen flow.

Table 1 exemplifies some experimental working conditions together with the relevant results, which have been achieved with the aid of the method according to the invention, with reference to the drawing below Use of the unit 19 for the selective hydrogenation and the hydrogen stream 20, but without recirculation des butene-1 in the isomerization zone.

Table 1 Tabel

Hydrocarbon,
substance electricity

C-J hydrocarbons

Isobutane

Isobutene

Butene-1

I, 3-butadiene

n-butane

trans-butene-2

cis-butene-2

C "hydrocarbons

total

kg / h 3ew.i

192

504

15520

15374

114

1005

3277

2016

33002

1 kg / h wt.%

0.5

1.3

40.8

40.5

0.3

2.7

8 _> 6

5.3

100th C.

176 40

2304 17Θ6

208 2285 2128

74.

9031

1.9

0.4 25.4.

19.7

3.2

25.2

23.4

0.8

100.0

17824

17160

47083

Gevi%

0.8

. ¹ I ²

37.9

36.4

0.2

2.7

8.8

0.2

100.0

8th.

kg / h

14th

368

544

146

16988

1460 5734 4144

29398

Gevi.%

0.1

1.2

0.5

57.8

5, C

19.5

14.1

100 j 0

10 kg / h weight%

14th

368:. 516 30 3500

38 85 47

4598

0.3

11.2

0.7 76.1

0.8

1.9

100.0

12th

kg / h

Gew.i

0.2

0.9

98.6

0.3

100.0

14 kg / h

2 603

1181 542 168 '

2496

0.1

24.2

47.3

• 21.7

6.7

lOOjO

15th

kg / h

208 5107 3329

92S2

Weight?

0.1

2.2

55.2

12.5

100.0

kg / h

22nd

1-57 222

Table 2 explains by way of example some experimental working conditions and the corresponding results, which were achieved with the aid of the method according to the invention, again with reference to the drawing, however without the unit 19 for the selective hydrogenation, but with recycling of the butene-1 into the isomerization zone.

Table 2 Tabel

Hydrocarbon stream

C, hydrocarbon

fabrics
Isobutane

Isobutene
Butene-1
n-butane
trans-butene-2

cis-butene-2

C -hydrocarbons

total

kg / h

161

422

12998

12076

342

2744

i 1688

Weight ¹

0.5

¹ J ³

41.0

40.6

2.7

Θ.6

5.3

31731

(100, c

4 kg / h ¹ 6Θ9

279 9023 6994

785 Θ951 8335

290

Weight%

2.0

0.8

25.5

19.8

2.2

25.3

23.6

0.8

35346

10.0 y 0

Weight

1.3

32.8

29.6

2.4

17.4

15.0

0.4

100.0

kg / h 850

701

227

19671

1627

11894

10023

44993

Weight%

1.9

1.6

0.5

43.7

3.6

26.4

22.3

100.0

10

kg / h

850 588

38 3262

63 177 113

5091

Weight%

16.7

11.6

0.7

64.1

¹ I ²

3.5

2.2

12th

kg / h

113

185

1566G

53

100.0

Weight%

0.7

.1,2

97.8

0.3

16017 100.0

14th
kg / h each 5

3675

19.8

30.3.

46.7

3.1

100.0

15th

kg / h weight?!

15th

400

0.1

2.0

10000 j 49.5

9795

20210 hoo.o

43.4

NJ N) M

21

kg / h

113 185

15681 Λ53

10000 9795

5 weight%

0.3

; 0.5

43.3

1.3

27.6

27 _; 0

36227

100.0

PATENT LAWYERS. .. »«,. · ... · \. ^β1

WUESTHOFF - ν. PECHMANN - BEHRENS - GOETZ

EURO PEAN PATENT ATTORNEYS

331830

DR.-ING. FRANZ WUESTHOFP DR. PHIL. FKEDA \ njESTHOFP (ig: 7 DSPL.-ING. GERHARD PULS (1952-1971) DIPL.-CHEM. DR. E. BARON OF PECH DR.-ING. DIETER BEHRENS DIPL.-tNG .; DIPL.-VIRTSCH.-ING. RUPERT

lA-57 222

Note: Snamprogetti S.p.A. D-8000 MUNICH SCHWEIGERSTRASSE

PHONE: (c§9) 66 2O JI TELEGRAM: PROTECT PATENT

TELEX: 524070

List of reference symbols

1 2 3

4 5 6 7 8

10 11 12 13 14 15 16 17 18 19 20 21 C. starting hydrocarbon mixture C. Stream from isomerization reactor

C. stream combined from 1 and 2, into the synthesis unit MTBE synthesis unit MTBE product stream
CH, OH in the synthesis unit C. stream without isobutene

C. stream without isobutene after selective hydrogenation

Fractionating column for isobutene

Isobutene stream

Fractionation column for butene-1

1-butene stream fractionation column for n-butane

n-butane stream butene-2 stream (ice and trans) isomerization reactor 1-butene stream to the isomerization reactor

1-butene discharge reactor for selective hydrogenation

H ₂ flow C. flow into the isomerization reactor

7227

Blank page

Claims (4)

Claims Process for the production of tert-butyl-alkyl ethers from a C. hydrocarbon starting mixture, which optionally also contains C, - and C ^ components and from which butadiene has previously been separated off, in which the butadiene-free or practically free C. hydrocarbon starting mixture fed into a unit for the synthesis of tert-butyl alkyl ethers which uses a catalyst in the form of an acidic ion exchange resin, preferably a sulfonated divinylbenzene-styrene resin contains that in the C. hydrocarbon starting mixture Isobutene contained is reacted with an aliphatic alcohol and the tert-butyl-alkyl ether obtained from the remaining (! .- hydrocarbons is separated, thereby g e k e η η records that the remaining C. hydrocarbon e by fractional distillation in two or three stages into saturated hydrocarbons as well as separating into butene-1 and butene-2 and converting the latter partly into isobutene in an isoraerization stage and the hydrocarbon fraction obtained, essentially butene-1, butene-2 and isobutene, if appropriate along with heavy products and saturated components, in the unit for that Recirculates synthesis of tert-butyl alkyl ethers. LA-57 222 - 2 - 2. The method according to claim 1, characterized in that one is in the isomerization stage a hydrocarbon mixture is obtained in which the molar ratio of butene-1 to butene-2 is thermodynamic Equilibrium corresponds, while the molar ratio of isobutene to linear butenes is 0.6 to 0.3. 3. The method according to claim 1 or 2, characterized in that one from the isomerization stage obtained hydrocarbon fraction first with that of butadiene free or practically free (^ -hydrocarbon stream mixed and then in feeds the synthesis zone. 4. The method according to any one of the preceding claims, characterized in that one in the Isomerization only feeds the cis- and trans-butene-2. 7227