JPH0640983A - Preparation of amyl methyl ether - Google Patents

Abstract

PURPOSE: To provide a method for efficiently and economically converting liquid light hydrocarbons into TAME.

CONSTITUTION: A liquid hydrocarbon (4-12C) supply material containing nitrile is prepared and the supply material is mixed with an alcohol selected from methanol, ethanol, propanol or a mixture of them. The obtd. mixture light hydrocarbon supply material is treated under controlled conditions to obtain a product containing 5C alcohol azeotrope supply material substantially containing no nitrile. Then the 5C alcohol azeotrope is brought into contact with a catalyst under etherification condition to obtain amylmethylether.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to FCC containing nitrile.
From a light hydrocarbon stream to teramyl methyl ether (TA
ME).

[0002]

MTBE and TAME are very often used as fuel extenders and octane number improvers in the production of unleaded gasoline. In general, satisfactory octane numbers can only be obtained by changing the composite additive in gasoline, ie by increasing the lead content of gasoline. It is well recognized that lead-free gasoline is desirable. The presence of lead additives in gasoline results in pollutants in the exhaust gas from internal combustion engines, polluting the entire environment. The use of alternatives to improve the octane number of gasoline in place of the feedstock contained in the gasoline compounds will result in cleaner gasoline and improved air quality and environment.

Today, MTBME is frequently used as an octane number improving additive for TAME because of its processing considerations. However, TAME is much more desirable as an octane number improving additive.

Various methods for producing MTBE (methyl t-butyl ether) and TAME (methyl t-amyl ether) have been developed. Typical ethylation methods include US Pat. Nos. 5,001,292, 4,925,4
55, 4,827,045 and 4,830,635
There is one disclosed in the issue. Other known methods include those disclosed in US Pat. No. 4,025,989. In many of these conventional processes, primary alcohols such as methanol are reacted with olefins having a double bond on the third carbon atom, such as isobutylene and isoamylene, to obtain ethers as an additive for gasoline. . It is also known to react an alcohol with an olefin in the presence of a catalyst. Lewis acids (sulfuric acid) and organic acids (alkyl and allyl sulfonic acids) are known as catalysts. Particularly suitable catalysts for these reactions are the ion-exchange resins in the acid form, for example Rohm and Haas or Bayer product K263.
1. There is a product name "AMBERLST15".

[0005]

Although various hydrocarbon feedstocks can be used to produce MTBE and TAME, in petroleum refining processes, TAME is produced from the light hydrocarbon stream produced by fluid catalytic cracking (FCC) refining processes. It is especially beneficial to treat. When treating an FCC hydrocarbon stream under etherification conditions to form TAME, the catalyst used in the treatment is rapidly degraded. That is, the catalyst is deactivated. Since the catalyst used in the conventional treatment is relatively expensive, such deterioration of the catalyst not only lowers the treatment efficiency but also increases the treatment cost. Prior art In particular, none of the above-mentioned prior inventions solves such a problem.

Treatment methods for converting hydrocarbon streams, especially F
It is highly desirable to convert the light naphtha hydrocarbon stream from the CC refining process to TAME which overcomes the problem of catalyst degradation.

An object of the present invention is to provide a method for efficiently and economically converting liquid light hydrocarbons into TAME.

Another object of the present invention is to prevent the deterioration of the catalyst used in the ethylation.

[0009]

SUMMARY OF THE INVENTION The present invention provides a liquid hydrocarbon C ₄ -C ₁₂ feedstock containing a nitrile, the feedstock being selected from the group of methanol, ethanol, propanol and mixtures thereof. Mixing with alcohol and treating this mixed light hydrocarbon feed under controlled conditions to obtain a product containing substantially nitrile-free C ₅ -alcohol azeotrope feed, C under etherification treatment conditions. _The method is characterized in that ₅ -alcohol azeotrope is contacted with a catalyst to obtain amyl methyl ether.

The above process is characterized in that the light hydrocarbon feedstock and the alcohol are treated in a distillation column.

In the above method, the distillation column is operated at about 0 to 50 psig.
And a temperature of 167 to 194 ° F. and a weight ratio of isoamylene to alcohol of 0.4 to 0.6.

The above process is characterized in that the feed is an FCC naphtha hydrocarbon feed.

The method is characterized in that the nitrile comprises propionitrile.

The above method is characterized in that the light naphtha FCC cut is substantially a C ₅ cut.

The above method is characterized in that the acidic ethylation catalyst is an ion exchange resin.

The above process is characterized in that the feed to the distillation column is mixed with alcohol in an amount of 2.0 to 4.0% by weight, based on the total feed.

The method is characterized in that the alcohol is methanol.

The above process is characterized in that the nitrile content of the C ₅ -alcohol azeotropic feed is 0 to 2 ppm.

[0019]

In accordance with the method of the present invention, the alcohol added to the feed prior to the distillation process destroys the C ₅ -nitrile azeotrope in the feed, reducing the nitrile concentration in the product after distillation.

[0020]

EXAMPLE A conventional method for producing TAME from a light hydrocarbon feedstock obtained from a catalytic cracking process (FCC) is shown in FIG.
Shown in. The apparatus 10 in the figure includes an FCC manufacturing apparatus 12 and an etherification region 14. The etherification region is a light hydrocarbon feedstock with ether-rich additives, especially TAME.
Is to be converted to. In the prior art, the light hydrocarbon feedstock from the FCC production unit 12 is sent via pipe 16 to unit 18, where the mercaptans in the hydrocarbon feedstock are oxidized. The treated product from unit 18 is sent to distillation unit 22 via pipe 20 and the C ₅ -rich product produced therein is sent to etherification region 14 via line 24. The line 26 from the bottom of the distilled oil 22 is rich in C ₆ +. The ether-rich TAME product is removed from the etherification zone 14 via line 28.

The typical composition of the product from the FCC production unit 12 output via line 16 is isobutane 2
7 wt% (wt%), isoamylene 5-10 wt%, diolefin 1-2 wt%, nitrogen concentration 22-27 ppm
And the nitrile content is 6 to 10 ppm. The feedstock delivered from unit 18 via line 20 has a nitrile concentration of 6-10 ppm. When this feedstock is processed under appropriate conditions in the distillation unit 22, a C ₅ -rich product is obtained above, the nitrile concentration of which is 1
It is 0 to 14 ppm. The upper product from line 24 is mixed with the alcohol from unit 28 and then sent to the etherification zone 14, where the pressure is 150-300 ps.
i, a temperature of 130 to 140 ° C., a methanol / isoalkyne ratio of 1.00 to 1.50 mol / mol, and a hydrogen / diolefin ratio of 1.5 to 3.2 mol / mol.

The catalyst used in the etherification reaction in the conventional method is a product K of Rohm, Haas and Bayer.
An acidic ion exchange resin such as the 2631 trade name "AMBERLIST" is used.

When carrying out the process of the invention as described above with reference to FIG. 1, the catalyst in the etherification zone deteriorates with time. This results in reduced processing efficiency and increased manufacturing costs.

FIG. 2 shows an apparatus for carrying out the method of the present invention, in which the same reference numerals as in FIG. 1 indicate the same elements. That is, the product from the FCC manufacturing apparatus 12 is sent to the unit 18 via the line 16 and the marcaptan is oxidized. The product from unit 18 is finally sent to distillation unit 22 via line 20 and the C ₅ -alcohol azeotrope-rich upper product is sent to etherification region 14 via line 24. In the case of the present invention, the unit 30 is provided on the downstream side of the unit 18 and on the upstream side of the distillation unit.
In particular, an alcohol selected from the group consisting of methanol, ethanol, propanol and mixtures thereof is produced and mixed with the feed to the distillation unit 22 via line 20. The C ₅ -nitrile azeotrope in the feed, in particular propionitrile, is then destroyed by the mixed alcohol. We have greater affinity C ₅ is the alcohol C ₅ - is because forming the alcohol azelate ot ropes.

The feed stream is distilled in unit 22 to give C
_{The 5} -alcohol azeotrope and the C ₆ -alcohol azeotrope are separated and then sent to the etherification zone 14. The nitrile content in the feed to the etherification zone is below 2 ppm. The remaining nitrile from the feed is collected in distillation unit 22 via line 26.

In order to remove substantially all of the propionitrile from the feed in the distillation unit 22, the amount of alcohol introduced in line 20 depends on the distillation unit 22.
Proportional to the amount of C _{5 in} the feedstock to. This amount of alcohol is at least 10 wt relative to the amount of C _{5 in} the feed.
% Is required. This amount for the light hydrocarbon stream from the FCC production unit will be 2-4 wt%.

C _{5 in} the feed to distillation unit 22 has a greater affinity for the introduced alcohol than for propionitrile in the feed gas. Thus, when the feedstock is distilled in unit 22, C
The stream of ₅ becomes substantially nitrile-free, and the nitrile concentration becomes 2 ppm or less.

The distillation unit has a pressure of about 0-50 psi,
It operates at a temperature of about 167-194 ° F and an isoamylene / alcohol weight ratio of 0.4-0.6. The substantially nitrile-free upstream is mixed with alcohol and etherified as in the prior art above. The condition is that the pressure is 150 to 300 p in the case of TAME manufacturing.
si, temperature 130-140 ° F, methanol / isoalkyne ratio 1.00-1.50 mol / mol, hydrogen / diolefin ratio 1.5-3.2 mol / mol.

Experimental Example 1 In order to confirm the deterioration of the catalyst used in the etherification treatment with a nitrile such as propionitrile or acetone nitrile, a C ₅ -rich untreated FCC supply having the following composition (wt%) was supplied. The material was etherified in the presence of AMBERLIST ion exchange catalyst.

[0030]

[Table 1]

The processing conditions were as follows.

[0032]

[Table 2]

Shown in FIG. 2 is the conversion of feedstock to the ether rich product TAME over time.
To show the effect of the pretreatment according to the present invention, the same feed was pretreated with 10 wt% methanol to C ₅ to obtain a treated feed having the following concentration.

The treated feed was then etherified at the same process conditions as above. FIG. 3 shows the degree of deterioration of the catalyst used for such treatment, and further for the etherification treatment. As can be seen from this figure, after 60 days, the effectiveness of the catalyst in the etherification process with the treated feed according to the invention is substantially the same as the result with the untreated catalyst. It can be seen from Table 1 that the effectiveness is reduced in the case of the catalyst not treated with. From this, the effect of the pretreatment is clear.

Experimental Example 2 In order to show the effect of adding alcohol to the feed material, the feed material having the composition shown in Table 3 was treated in a distillation unit.

[0036]

[Table 3]

The processing conditions were as shown in Table 4 below.

[0038]

[Table 4]

The resulting C ₅ overhead products were compared for nitrile removal and the net nitrile concentration loss of the methanol treated feed was over 80%.

The present invention can be carried out by a method other than the above-described embodiment without departing from the spirit and basic characteristics of the present invention. Therefore, the above-described embodiments and drawings are not limited thereto, and modified embodiments equivalent to the basic configuration of the present invention are also included in the present invention.

[0041]

INDUSTRIAL APPLICABILITY According to the present invention, the alcohol added to the feed material before the distillation treatment destroys the C ₅ -nitrile azeotrope in the feed material to reduce the nitrile concentration in the product after distillation. Therefore, deterioration of the catalyst is effectively prevented.

[Brief description of drawings]

FIG. 1 is a flow diagram of a conventional process.

FIG. 2 is a flow chart for the process of the present invention.

FIG. 3 is a graph over time of the reduction in the effect of nitriles on the acid catalytic activity when etherifying a light hydrocarbon feedstock to TAME.

[Explanation of symbols]

 10 ... Device 12 ... FCC manufacturing device 14 ... Etherification region 18 ... Unit 22 ... Distillation unit

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[Procedure amendment]

[Submission date] June 15, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

In the above method, the distillation column is operated at about 0 to 50 psig.
And a temperature of 167-194 ° F. and a weight ratio of isoamylene to alcohol of 1-5 .

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Jose Castor Gonzalez Venezuela, Ed. Miranda, San Antonio de los Altos, Apt. 38, Piso 9, C. El Pickacho. Les. El pickacho (no address)

Claims (10)

[Claims] 1. A liquid hydrocarbon C ₄ -C containing nitrile.
_{12 A} feedstock is prepared, the feedstock is mixed with an alcohol selected from the group of methanol, ethanol, propanol and mixtures thereof, and the mixed light hydrocarbon feedstock is treated under controlled conditions to produce substantially nitrile. Not including C
Process for producing amyl methyl ether, characterized in that a product containing ₅ -alcohol azeotrope feedstock is obtained and C ₅ -alcohol azeotrope is contacted with a catalyst under etherification conditions to obtain amyl methyl ether. . 2. The method of claim 1 wherein the light hydrocarbon feedstock and alcohol are treated in a distillation column. 3. The distillation column is operated under a pressure of about 0 to 50 psig, a temperature of 167 to 194 ° F., and a weight ratio of isoamylene to alcohol of 0.4 to 0.6. The method according to claim 2, wherein 4. The method of claim 1, wherein the feedstock is an FCC naphtha hydrocarbon feedstock. 5. The method of claim 1, wherein the nitrile comprises propionitrile. 6. The method of claim 1, wherein the light naphtha FCC cuts are substantially C ₅ cuts. 7. The method of claim 1, wherein the acidic ethylation catalyst is an ion exchange resin. 8. A process according to claim 1, characterized in that the feed to the distillation column is mixed with alcohol in an amount of 2.0 to 4.0% by weight, based on the total feed. 9. The method of claim 1, wherein the alcohol is methanol. 10. Process according to claim 1, characterized in that the nitrile content of the C ₅ -alcohol azeotropic feed is 0 to 2 ppm.