DD157700A5 - PROCESS FOR OBTAINING C LOW 2 TO C LOW 4-ALCOHOLS - Google Patents

Abstract

The invention relates to a process for obtaining C 2 to C 4 deep alcohols from aqueous mixtures which can be added directly to gasoline by reacting the aqueous mixture with a tertiary olefin in the presence of an acidic catalyst at a temperature of 40 to 90 Degree C and a space velocity of 5 to 25l / h, based on the liter volume of the catalyst reacted. The preferred catalysts are ion exchange resins in the acid form, especially those having sulfonic acid groups. The reaction temperature and rate are critical to minimize side reactions, especially ester formation.

Description

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Method for obtaining C _? - to C. alcohols

Field of application of the invention

The invention relates to a process for the recovery of C _{2 to} C ₄ alcohols from their aqueous mixtures, which are suitable in terms of their purity as propellants instead of gasoline.

Characteristic of the known technical solutions

It is known that ethanol has a very favorable kill count so that it can be used in fuel blends to reduce the level of lead alkyl additives or aromatic content of the gasolines.

Ethanol is usually produced on an industrial scale by fermentation of carbohydrates. The alcohol content of the fermentation or fermentation products of sugary juices or liquids is less than 10 %. The other stages of the process are directed to the recovery of the alcohol from the fermentation products and constitute a series of distillation stages until an oeotropic mixture of water and ethanol is obtained which has a water content of 4.4% by weight ₆ % at atmospheric pressure *

However, this water content is too high for the use of ethanol directly in fuels, so that a discharge stage is necessary «

The rectification stages and in particular the final drainage naturally have a very negative effect on the

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Cost of purchase of the ethanol that can be added to the gasoline «

This fact led to extensive research into the optimization of heat recovery from conventional systems and a series of proposals for an alternative to drainage. "

Absolute alcohol can currently be obtained by azeotropic distillation with benzene.

Several alternatives have recently been proposed, on the following basis; Stripping water by selective adsorption on starchy substances and preferably on textile fibers; Extraction with solvents under critical conditions; Application of membranes which are impermeable to, a component; Adsorption on molecular sieves whose pore size does not pass water, and finally distillation under reduced pressure *

All these proposals have a serious drawback, which is that the yield of the liquid product is reduced and the operating costs are substantially increased and special equipment is required, so that the purchase costs are very high,

The object of the invention is to provide an improved process with which it is possible to prepare C "to C" alcohols of such purity that they can be added to fuels or fuels, according to conventional methods.

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driving without a simultaneous operations management the main advantages of simple B _e and good liquid yield ruüßten be abandoned _e

Explanation of the essence of the invention

The invention has for its object to reduce the water content by a suitable addition,

According to the inventive method, the alcohol / vVasser-Gernisch from the respective production with a tertiary olefin or an olefin is reacted, thereby oer water content is lowered, as the olefin is reacted to form a tertiary alcohol with it. The reaction product after stripping the unreacted olefins is a mixture which can be added to the fuels in conventional proportions, without resulting in a phase separation even at temperatures below -20 C »

The reaction of the tertiary olefin with water is carried out with the aid of conventional catalysts, such as those used for the hydration of olefins, such as mineral acids, Lewis acids or ion exchange resins, especially those with SO "H groups on polystyrene, divinylbenzene or polyphenols, the ways-n are preferred for their ease of use.

The operating conditions must be carefully selected, as too high temperatures or too low throughput will degrade the selectivity due to the competing reaction of the formation of (esters) ethers, which could dominate. "

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The latter reaction is to be prevented as far as it .is possible in practice, since this is consumed tertiary olefin which is needed for the reaction with water, so that the formation of tertiary alcohol decreases. The tertiary alcohol is desirable because it has a solubilizing effect on the remaining water,

The temperature is preferably kept between 40 and 90 C under a pressure which is selected such that the hydrocarbon streams to be processed are in the liquid or gaseous phase, as appropriate *

When operating in the liquid phase, so one should keep the Raumgeschvvindigkeit at Oer implementation, based on the liter volume of the catalyst, 5-25 1/1 "h,

Execution gjsb_ei $ p_ Ie __!

The invention will be explained in more detail below with reference to some examples.

In the accompanying drawing show;

Fig. 1: a flow chart of an embodiment of the method according to the invention;

FIG _e 2: a flow diagram of another embodiment of the method "according to the invention

In Fig _e 1 is a flow chart of an embodiment of the method according to the invention with reference to an aqueous mixture

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of ethanol and an olefin fraction containing isobutene,. shown. The alcohol mixture 1 and the olefin fraction 3 are fed together with the reflux Qlefin 2 via line 4 in the reactor R-I The reaction product passes via line 5 in the rectification column C-I. From the bottom of this column ^ ethanol is discharged together with the reaction product and unreacted water via line 6. At the top of the column is obtained via line 7, an olefin fraction, which is partly returned to the reactor R-I and discharged in part via line 8.

Fig. 2 shows a flow chart corresponding to Fig. 1, but without olefin reflux.

The invention will be further illustrated by the following examples

Example 1 illustrates the possibilities of the process according to the invention. From this it can be seen that it is possible to obtain a product which is completely miscible with gasolines and so on. an improvement of the yield based on the alcohol employed, in aer order of 18% at the expense of a gaseous product such as isobutene is achieved low temperatures During the same time, which gas can not be added directly "

Comparing the results from Examples 2 and 3, one can see how important the limitation on the conversion of ethanol can be. If it is not working at low flow rates, the result is a product which, when mixed with gasoline, has a higher turbidity temperature.

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Comparing the results of Examples 4, 5 and 6, it can be seen that at the same throughput rate the reaction temperature becomes critical. In these examples, the optimum temperature is 70 C,

l (Fig * I)

In a tubular reactor, the ion exchange resin in the acid form macroporous "Amberlyst 15" contains, was an alcohol mixture containing 28.20 wt ethanol with 7 wt «~ parts, -% of water, 61.5 parts by weight of olefin fraction having led back 6, 4% by weight of isobutene and 10.36 parts by weight of olefin fraction with 50% by weight of isobutene, reacted. The reaction mixture contained:

Wt .-%

Non-reactive butenes 62.7

Isobutene - 9.1

Ethanol '26.2

Water 2.0

The mixture was at a space velocity of 10 l / h, l and a temperature of 70 ι ne reaction product contained:

and a temperature of 70 C, whereby the received

Unreacted butenes 62.7

Isobutene 4 _t 3

Ethyl tert-butyl ether 3,6

tert-Qutylalkohol. 3.8

Ethanol. · 24 * 6

Water 1.0

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The subsequent fractionation of the reaction product was carried out in a rectification column, from which 33 parts of soil products of the following composition were removed:

, Wt .-%

Ethanol 74/5 water 3.0

tert -butyl alcohol · 11.5

Ethyl tert-butyl ether 11.0

and 67 parts of top product of the following composition:

Gevj .-%

Non-reactive butenes 93 ₇ 6

Isobutene "16,4

Of these, 61.5 parts were returned as stream 2 to the reaction; 5.5 parts were fed via line 8 to another use.

The bottoms product from line 6 could be added directly to gasolines without any segregation.

For comparison, in the following, the turbidity temperatures of ethanol batch 1 (mixture A) and the reaction product are given 6 (mixture B), and electricity while at jevveiis 10% additive to a hydrocarbon containing 30 Gevu-% aromatics and 70 Gevi _t - % saturated hydrocarbons *

Turbidity temperature C

Mixture A> -i 20

Mixture D <-20

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8 2)

In the tubular reactor according to Example 1, a stream of 34.1 parts by weight of ethanol with 7.3 % of water and 65.9 parts by weight of olefins was reacted with 50.7% by weight of isobutene on the ion exchange resin. The reaction mixture in the line contained:

Non-reactive butenes 32.5

"Isobutene · 33.4

Ethanol 31.6

Water 2.5

This mixture was reacted at 60 C at a space velocity of 1.5 1 / 1.h. The reaction product in line 5 contained:

Wt .-%

Unreacted butenes 32.5

Isobutene '2.5

Ethyl tert-butyl ether 45.7

tert-butyl alcohol 7,9

Ethanol 10,7

Water . 0.7

Fractionation of the reaction product in a rectification column gave 65 parts of bottoms product of the following composition:

Ethyl tert-butyl ether 70.4

tert-butyl alcohol 12.1

Ethanol 16.4

Water l _s l

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The water content, based on the. Sum of the alcohols was 3.7

The top product in line 8 from the rectification column C-I were 35 parts of olefin fraction of the following composition:

Unreacted butenes 92.9

Isobutene 7.1

The clouding temperature of a mixture of 10 % by volume of the bottom product 5 with 90 % by weight of a hydrocarbon fraction of 70 % by volume of saturated hydrocarbons and 30 % by weight of aromatics was -12 ° C.

3 _i (FIG. 2)

In the tube reactor with the ion exchange resin of Example 1, a mixture of 34.2 parts by weight of ethanol with 7.8 % of water and 65.8 parts by weight of olefins was reacted with 48.2 g / _{t of} isobutene.

The reaction mixture contained:

Gevu-%

tJicht-reactive Dutene 34,1

Isobutene 31.7

Ethanol 31.5

Water "· 2 , 7

and became riotous at 16 1/1. h at 60 C unoccupied, wherein a reaction product containing

~ 10 -

Nicbtumgesetzt Butene Isobutene

Ethyl-1-tert-butyl ether tert, but-butyl alcohol

water

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Gevu-%

34.1 22.9 5.5

7.9 28.9 · 0.7

then rectified in a column and 43 parts of bottom product of the following composition:

Ethyl tert-butyl ether tert-butyl alcohol ethanol

water

Weight J 12.8 18.4 67.2 1.6

The water content, based on the sum of the alcohols, was 1.8% by weight. "

57 parts of overhead product containing 59.8% by weight of unreacted butenes and 40.2% of isobutenes were obtained from the rectification column.

The cloud point temperature of a mixture of 10 wt, -% bottom product and 90 wt, -% of hydrocarbon mixture of 70% saturated hydrocarbons and Gevu- Gevu- 30% aromatics was <-20 ⁰ C,

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O · 2)

In the tube reactor with the ion exchange resin, a mixture of 31.5 parts by weight of ethanol with 7.5 % water and 68.5 parts of olefin with 50.8% by weight of isobutene was set.

The reaction mixture contained:

Weight-JS '

Non-reactive butenes 33.7

Isobutene 34.8

Ethanol 29.1

Water _y 2,4

It was reacted at a space velocity of 20 1/1 h and at a temperature of 60 ° C «

The reaction product contained:

Gevv.-Jij

I used butene 33,7

Isobutene · 25.7

Ethyl tert-butyl ether 6.5

tert-outyl alcohol * 7.2

Ethanol 26.2

Water · 0.7

In the following fractionation, 40.6 parts of bottoms product of the following composition were obtained from the rectification column;

Ethyl tert-butylther 16.0

tert-butyl alcohol 17.7

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Ethanol. 64.6

Water 1.7

The water content, based on the sum of the alcohols, corresponded to 2 Ge \ Nc ~% »

The overhead product of 59.4 parts contained 56.7% by weight of unreacted butenes and 43.3% by weight of isobutene,

A mixture of 31.5 by weight was as above, parts by ethanol with 7.5% water and 68.5 T _e ilen olefin 50.8 wt .- ^ o isobutene used *

The reaction mixture contained:

Non-reactive butenes. 33.7

Isobutene 34.8

Ethanol 29.1

Water · .2,4

and was converted at a space velocity of 20 1 / 1.h at 70 C «

The reaction product contained;

By weight of SS

Unreacted butenes 33.7

Isobutene. 14.0

Ethyl tert ~ _e -butyläther 27.3

tert-butyl alcohol 8.1

Ethanol. 16.5 ·

Water 0.4

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In the following fractionation in a rectification column, 52.3 parts of bottoms product were obtained

Wt .- ^

Ethyl tert-butyl ether 52.2

tert-butyl alcohol 15.5

Ethanol 31.5

Water 0.8

wherein the water content, based on the sum of the alcohols, 1 * 7 % corresponded.

The overhead product of 47.7 parts contained 70.6 wt .-% unreacted butenes and 29.4 Gevv, ^ ^ isobutene,

2®i.§ £ i ^ L_§. ( ^Fi 9 * ² )

Upwards, a mixture of 31.5 parts by volume of ethanol with 7.5 % of water and 68.5 parts of olefin fraction was reacted with 50.8 parts by weight of isobutene.

The reaction mixture had the following composition:

55 parts by weight

Nonreactive butenes 33.7

Isobutene 34.8

Ethanol 29.1 ·

V / asser. 2.4

It was umäoetzt with a space velocity of 20 1 / 1.h at 80. C «

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- 14 The reaction product contained:

Unreacted butenes 33.7

Isobutene 9.0

Ethyl tert-butyl ether 37.1

tert-butyl alcohol 7.2

 Ethanol 12,4

"Water 0.6

The following fractionation in a rectification column gave 57.3 parts of bottoms product containing

Ethyl tert-butyl ether 64.7

tert-butyl alcohol 12,6

Ethanol 21,6

Water . 1.1

the water content, based on the sum of the alcohols, corresponded to 3.1 Gevi, -% ,

The overhead product of 42.7 parts contained 78.9 gevi, -% unreacted butenes and 21.1 gevj, ~% isobutene,

Claims (4)

1 egg I method for the recovery of gasolines C _? ~ to C. alcohols from hydrous mixtures, characterized in that they are treated with a tertiary olefin or an olefin fraction in the presence of an acid catalyst such as a mineral acid, a Lewis acid or an ion exchange resin in the acid form. 2 # Method according to item 1, characterized in that one uses with sulfonic acid groups as the ion exchange resin in the acid form, 3 ". Method according to item 1 or 2, characterized in that the reaction is carried out at 40 to 90 ° C. ³ ^ * ^s * ^oil AP C 07 C / 228 774/6 59 007 11 4. The method according to item 1 to 3, characterized in that one carries out the reaction at a space velocity of 5 to 25 l / h, based on the liter volume of the catalyst. For this 1 page drawings