SU858557A3 - Method of producing tert-alkyl ethers - Google Patents

Abstract

1506312 Tertiary alkyl ethers SNAMPROGETTI SpA 13 May 1975 [21 May 1974] 20209/75 Heading C2C A tertiary alkyl ester is produced by reacting an alcohol with an olefin having a carboncarbon double bond on a tertiary carbon atom in the presence of an ion-exchange resin in atleast two stages, whereinin one stage the alcohol is present in excess and in another stage the olefin is in excess. The reaction may be carried out using two reactors; all of one reactant is fed to one reactor while all or part of the other reactant is fed to the other reactor, and reaction products are at least in part circulated from one reactor to the other. The invention is exemplified by the reaction of isobutene in a mixed olefin stream with methanol to form methyl tertiary butyl ether. A suitable apparatus is described. Reference has been directed by the Comptroller to Specification 1,176,620.

Description

(54) METHOD FOR OBTAINING TERT-ALKYL ETHER

one

The invention relates to methods for producing tert-alkyl ethers that are widely used in organic synthesis.

A known method of producing tertalkyl esters by reacting in the liquid phase unsaturated hydrocarbons (iobutylene, isoamylenes) mixed with other hydrocarbons with methanol at a ratio of 1-6 mol of alcohol per mole of unsaturated hydrocarbon, temperature 50-90 s, passing the reaction mixture through Amberlist-15 as a catalyst with a flow rate of 5.0–40 l / l of catalyst — h. Conversion in the case of isobutylene does not exceed 92%, in the case of isoamylenes it does not exceed 70% 1.

The disadvantage of this method is the low content of c-alkyl esters. finite retracted riqiTOKe. Thus, in the case of methyl tertiary butyl ether (MTBE), the withdrawn stream is practically an azeotrope (MTBE-85%, methanol - 15%), and it is necessary to use expensive operations to isolate and purify the target ester. In addition, the use of an excess of one of the reagents leads to a non-productive consumption of initial reagents.

The purpose of the invention is to simplify the process.

This goal is achieved by the fact that according to the method for producing tert-alkyl ethers by the interaction of methanol and olefin in the liquid phase

10 in equimolecular ratio at 50–90 ° C and a space velocity of 5–40 l / l of catalyst. The process is carried out in two stages, the first of which uses an excess of methanol at a mole

15 ratio of isoolefin to methanol 0.62 - 0.77, on the second - an excess of isoolefin with molar ratio isoolefin - methanol 2.15 - 2.80.

20

Preferably in the first stage

the process is conducted with the whole amount of one of the reagents and the stream leaving the second stage, and on the second stage of the 25th day with the whole amount of the reagent and the stream leaving the first stage. .

FIG. 1 and 2 show the variants of the preparation of a tert-alkyl system.

30 Zephyrs.

The process is carried out in the presence of an ion exchange resin — Aberlist-15. As follows (FIG. 1

Methanol via line 1 is fed to the reactor 2 along with the olefin stream leaving the column 3. At the same time, the reaction mixture contains an excess of methanol, which ensures a high conversion of isoolefin in reactor 2, from which stream 4 is fed to a distillation column 5, from the top of which an olefin fraction 6 with less than 20% olefin is taken, and from the bottom part a mixture of methanol and 7, and this mixture together with olefinic feed 8 is fed to the next reactor 9. The reaction mixture in this solution contains an excess of olefin, due to which the methanol conversion is high. The effluent stream 10 from reactor 9 goes to the distillation column 3, from the bottom of which MTBE 11 is picked up at a high frequency, and from the upper part is a stream of olefins, which is recycled to reactor 2.

An embodiment of the process (Fig. 2) is also possible, according to which olefin is fed not only to reactor 9, but is distributed between reactors 2 and 9.

The flow rate in the reactor 540 l / l of catalyst-h. The process temperature is 60-70 ° C, the total conversion of mb tanol in the preparation of MTBE is up to 96.7% with a selectivity of 100%, the conversion of isobutylene to 98% with a selectivity of 97-98%. In the case of the use of isoamylenes, the total conversion of reagents reaches 77% as starting components, and the content of ether in the outlet stream

92.33%.

f

The proposed method is simpler because; allows to significantly increase the content of the target ester in the withdrawn final stream and in the case of MTBE to achieve without using additional purification a high degree of purity of the target ester (98-99%),

In this case, the method allows to avoid unproductive consumption of initial reacents, since equimolecular amounts are used in sum (taking into account the effect of both reactors).

In addition, the advantage of the proposed method is the high degree of conversion of the initial reagents while maintaining the high selectivity of the process both in alcohol and in olefin. Under the proposed conditions, the reaction proceeds with virtually no adverse processes for the oligomerization of olefins.

Example 1. 21,11 weight.h. methanol via line 1 is introduced into the olefin stream, deduction from the column 3, consisting of and 2 .. (,. 8 parts of isobutylene.

43.43 parts by weight linear olefins and 0.35 parts of methanol. A mixture in which the molecular ratio of isobutylenemethanol is 0.62 is fed to reactor 2, where they react in the presence of Amberlist-15 at 60 ° C at a rate of 5 liters / l of catalyst-hour and at a pressure sufficient to maintain the system in the liquid phase .

The stream 4 leaving reactor 2, which consists of 8.46 parts of methanol, 36.76 parts of MTBE, 0.62 parts of isobutylene and 43.43 hours, linear butenes, is fed to a distillation column 5. Then from on line 6, 44.95 parts of the fraction having the following composition,% by weight, are withdrawn:

Isobutylene 1,4

Methanol2.0

Linear olefins 96.6

From the bottom of column 5, along line 7, 35.76 parts of MTBE and 7.56 methanol are withdrawn, which are mixed with 37.00 isobutylene and 43.43 parts of linear butenes 8 and fed to reactor 9, in which they react over Amberlist -15 at 60 ° С and a speed of 40 l / l of catalyst.

In a reactor 9, the molar ratio of isobutylene to methanol is 2.8. The stream 10 leaving the reactor 9 consists of 55.60 parts of MTBE, 0.35 hours of methanol, 23.38 parts of isobutylene,

53.43h linear butenes and 0.99 parts of diisobutylene.

The reaction product 10 is fed to a distillation column 3, from which 23.38 parts of isobutylene, 43.38 parts, linear buteno and 0.35 parts methanol are withdrawn via line 1, and these compounds are returned to reactor 2. From the bottom columns 3 through line 11 take 56.59 parts. MTBE 98.25% purity.

The total methanol conversion is 96% with a selectivity of 100%, while the conversion of isobutylene is 98% with a selectivity

QTa -7 / ъ.

Example 2. (the process is carried out according to the scheme shown in Fig. 2). 32.12 weight.h. methanol 1 is mixed with a stream of olefins from the column 3, consisting of 0.98 parts of methanol, 40.73 parts of linear butenes and 23.94 parts of isobutylene and 12 parts of olfinic feedstock, which consists of

16.44 hours isobutylene and 16.77 parts of linear butenes.

The reaction mixture, in which the isobutylene-methanol molar ratio is 0.72, is fed to reactor 2 at a rate of 5 l / l of catalyst, in which it reacts over Amberlist-15 at 60 ° C and sufficient pressure to maintain systems in the liquid state.

Reaction product 4, which consists of 10.67 parts of methane, 1.11 hours

isobutylene, 57.50 parts of linear butenes and 61.70 parts of MTBE are fed to the distillation column 5, from which 59.67 parts of the fraction having the composition, wt%, are taken from 6

Isobutylene1,9

Methanol1,8

Linear butenes 96.3. From the bottom of column 5, via line 7, 9.61 parts of methanol and 61.70 parts of MTBE are obtained.

The product 7 from the bottom 5 is combined with 39.66 parts of isobutylene and 40.73 parts of linear butenes (line 13), which is the remaining part of the olefin feed 8 and is reacted in reactor 9 at bOS and speed l / l catalyst hour 40. In this case, the isobutylene-methanol ratio is 2.35. Reaction product 10, consisting of 0.98 parts of methanol, 85.45 parts of MTBE, 23.94 parts of isobuty, volume rate, l / l of catalyst per hour

Total isobutylene conversion

Conversion of isobutylene to MTBE

Selectivity

Example 4 Olefin fraction Cj., Having the following composition, weight ,,%:

Inert olefins C 69.5 Isoamylenes30.5

subjected to interaction with an equimolar amount of methanol (with, in the presence of Amberlist-15 and with a volume velocity of 1 l / l of catalyst -h, a mixture of the following composition is obtained, wt.%: Olefins Cc normal, structure 61.05

Isoamylenes9.75

Methyl tert-amyl ether 24,74 Methanol4,46

Conversion of reagents 63%. Example 5. The olefin fraction Cg (example 4) is processed according to the scheme shown in FIG. 1. 7.58 parts by weight methanol 1 is mixed with the product from the top of column 5, consisting of 12.74 parts by weight. (isoamylenes) and from 36.82 parts by weight (Su inert olefins). This mixture, in which the molar ratio of isoamylenes to methanol is 0.77, is fed to reactor 2. The reaction is carried out at 70 s over Amberlist-15 II at a volume of 5pen, 40.73 parts of linear butenes and 0.88 hours. diisobutylene, the distillation column 3 is sent, separating 0.98 parts of methanol, 23.94 parts of isobutylene and 40.73 parts of linear butenes, which are returned to the reactor 2, as head cuts (line 1 ").

From the bottom of column 3 (line 11), 86.33 parts are obtained. MTBE is 99% pure.

0

The overall methanol conversion is 96.7% with a selectivity of 100%, the conversion of isobutylene is 98% with a selectivity of 98%,

Example 3. The raw material 9 fed to the actor 9 under the conditions of example 2 is reacted at two different temperatures and three different flow rates, and the following results are presented:

0 in the table.

40

8.5

40

8.5

44 63

55

5.5

55

42,5 37

41.5 46.5 41 43 77.5 82 68 83 93 68

Noah rate equal to 1 l / l catalyst-h.

Stream 4 from reactor 2 consisting

0 out of 3.52 parts of methanol, 12.94 parts of methyl tert-amyl ether (MTAE), 3.86 hours, nzoamylenes and 36.82 hours, inert components Cg-, are fed to a distillation column 5. From the top of the column 5 (stream 6) get 40,68 h,

5 fractions having the following composition, wt.%: Isoamylenes (9.48) and inert components C (90.52). From the bottom of column 5 a fraction is obtained consisting of MTAE (12.94 parts by weight) and

0 from methanol (3.52 parts by weight), mixed with olefinic feed consisting of isoamylenes (16.59 parts by weight) and from inert components Cg- (stream 8) (36.82 parts by weight ), and the resulting mixture

5 is fed to the reactor 9, the Reaction proceeding over Amberlist-15 at and at a volume velocity of 20 l / l of the catalyst h.

In the reactor 9 molar ratio

0 between isoamylenes and methanol is 2.15. The stream leaving reactor 9 consists of weight.H:

MTAE18,55

Methanol1,76

Isoamylenes 12.74

five

Inert components Cj 36,82

This stream is fed to the distillation column 3. From the upper part, an olefin stream is obtained consisting of isoamylenes (12.74 parts by weight) and inert components Cj- (36.82 parts by weight), which is returned to reactor 2. The product 11 obtained from the bottom of the column is a mixture (20.31 parts by weight) consisting of MTAE (91.33% by weight) and methanol (8.67% by weight

The total reagent conversion is 77%.

Example 6 (comparative). The reactor, which contains 3 kg of catalyst at 80 ° C, is fed with a volumetric flow rate of 40 l / l of catalyst, a mixture of 21 kg / h of methanol (0.65 kmol-h), 24.9 kg / h of isobutene (0.44 cpm-l) and 75.1 kg / h of other hydrocarbons.

The reaction mixture has the following composition, kg / h: 37.7 MTBE 7.3 methanol (0.9 isobutene and 75.1 other hydrocarbons.

The methanol conversion is 65%, while the isobutylene conversion is 96%.

The reaction mixture is continuously fractionated and gtamm is distilled as

76 kg / h of hydrocarbons and 0.8 kg / h of methanol are obtained, while at the same time, 37.7 kg / h of MTBE and 6.5 kg / h of methanol are obtained as the bottom drain. The percentage composition of the final stream,%: MTBE 85, methanol 15.

Claims (1)

1. The patent of Great Britain, 1.176.620, cl. C 2 C, pub. 07.01.70 (prototype). g CO-I P Rsh / ABOUT about 4s Ni h about f "b / V N