CS221292B2 - Method of preparation of alcohole with 2-4 atoms of carbon in the quality necessary for addition in the petrol - Google Patents

Abstract

An improved process is disclosed for producing petrol-grade C2-C4 alcohols from aqueous mixtures which contain these alcohols. The improvement is that the aqueous mixture is reacted with a tertiary olefin in the presence of a catalyst having an acidic character, preferably at a temperature of from 40 to 90 DEG C and at a space velocity of from 5 to 25 litres of reactants per litre of catalyst per hour. Preferred catalysts are acidic ion-exchange resins, especially those having -SO3H groups. The temperature and space velocity ranges are critical in order to minimize the parasitic ether- forming reaction.

Description

The present invention relates to a process for the preparation of C 2 -C 4 alcohols from aqueous mixtures containing them in a quality suitable for the gasoline additive.

It has long been known that ethanol has valuable octane rating characteristics, so that it can be used as such in the formulation of fuel compositions to reduce the percentage of alkyl lead additives or to reduce the aromatics content of gasoline.

Ethanol is generally produced on an industrial scale by fermentation of carbohydrates: in these processes, the percentage of alcohol in fermentation products of sugar-containing juices is below 10%. Subsequent production steps for the production of alcohol, comprising a sequence of distillations, result in an azeotropic mixture of water and ethanol containing 4.4% by weight of water at ambient pressure.

However, this ethanol still contains too much water to be suitable for direct use as a fuel additive, so that additional dehydration steps are necessary.

However, the rectification steps, and in particular the final dehydration step, have an adverse effect on the cost of obtaining ethanol in a quality suitable for the gasoline additive.

These circumstances have led to numerous studies on the optimization of heat recovery in conventional processing processes, as well as a number of proposals for modified dehydration operations.

Currently, absolute ethanol is obtained by azeotropic distillation with benzene.

Recently, however, modified methods have been proposed which are based on scrubbing water by selective absorption on starch substances and preferably on absorption on textile fibers, on solvent extraction in critical phase, on the use of membranes which are permeable to one component, for absorption on molecular sieves having pore dimensions sufficient to retain water and finally based on distillation operations at reduced pressures.

However, all the proposed processes have the serious drawback of reducing the liquid yield, requiring substantially higher operating costs and special apparatuses so that the cost of obtaining alcohol is high.

It has now been found that it is possible to produce C 2 -C 4 alcohols in gasoline grade without using any known method, while attaining economic advantages for the simplicity of the proposed operation and also for improving the liquid yield.

The invention therefore relates to a process for the preparation of C 2 -C 4 alcohols suitable for the addition to gasoline of a mixture comprising these alcohols and water, characterized in that the aqueous mixture is treated with isobutene in the presence of an acidic ion exchange resin as acidic. catalyst at a temperature of 40 ° C and a space velocity of 5 to 25 liters of feed per liter of catalyst per hour. In this process, the water content of the mixture is reduced since water reacts with isobutene to form a tertiary alcohol. The product obtained after separation of unreacted olefins is a mixture which can be added to the fuels in conventional proportions without phase separation even at temperatures below -20 ° C.

The reaction of adding isobutene to water can be carried out using conventional catalysts used to hydrate olefins such as mineral acids, Lewis acids and ion exchange resins; especially ion exchange resins having sulfone groups - SO 3 H on polystyrene, divinylbenzene and polyphenol matrices are suitable for greater ease of use.

The operating conditions have to be carefully chosen, because the use of too high temperatures or too low space velocities deteriorates the selectivity of the reaction, since the competitive reaction of forming the corresponding ether can prevail.

This reaction must be avoided as far as possible because it is isobutene away from its reaction with water, and as a result tertiary alcohol production decreases: tertiary alcohol is important because it has a solubilizing effect on the remaining water.

It is preferred that the addition reaction is carried out at a temperature of 40 to 90 ° C and at a pressure such that the hydrocarbon feed to be treated is either liquid or gaseous, depending on whether the liquid or gaseous operation is performed.

When operating in the liquid phase, the spatial reaction rate, expressed in liters of feed per liter of catalyst per hour, is 5 to 25 liters.

In the accompanying drawings, FIG. 1 illustrates a particular embodiment of the process of the invention relating to the treatment of an aqueous mixture comprising ethanol with an olefin fraction containing isobutene: the alcohol mixture 1 and the introduced olefin fraction 3 are fed together with the recycled olefin 2 to the R-reactor. 1; the reaction product 5 is fed to a rectification column C-1, from which ethanol is removed along with the reaction product and unreacted water 6. An olefin fraction is removed from the top of the column which is partially recycled to the R-1 reactor and partly discharged as product 8.

Fig. 2 is a diagram similar to Fig. 1, but without olefin recycling.

The following examples illustrate the process according to the invention without limiting it.

Example 1 discusses a scheme that explains the possibilities provided by the method of the invention. As is apparent, it is possible to obtain a product which is completely miscible with gasoline at low temperatures, while achieving improved yield of the starting alcohol in the order of% to the detriment of the gaseous product, such as isobutene which ^p Rimo added ^d of gasoline because it is not possible.

Comparison of the results according to Example 2 and Example 3 shows how important limiting ethanol conversion can be. In fact, when operating at a lower space velocity, a product is obtained which, when mixed with gasoline, has a higher cloud point.

Comparison between the results of Example 4, 5 and 6 in ^the azuje ^that at the same speed ^{p s} rostorov reaction temperature is of decisive importance: while the examples described herein, the optimum appears to be 70 ° C.

Example 1

The tubular reactor of FIG. 1, which contains a macroporous ion exchange resin in acid form, such as Amberly St I ^{y 5,} the reacted ^mixture containing ^the now obsolete 28.20 parts by weight of ethanol with ^{L (7%} oteahujmtéo hmotnostrnch in ^dy)

1, 61.50 parts of recycled olefin fraction

2 containing 6.4%, by weight of isobutene and 10.36 parts of 3 olefin fraction, containing ^50% by weight ^b iso-butene.

^{With this} month, this group has:

o / o unreacted butenes by weight62.7 isobutene .9.1 ethanol26.2 water2.0

The mixture did not react at 70 ° C at a space velocity of 10 liters per ^hour per ^{hour of} the catalytic catalyst to give the following reaction product 5:

% by weight

unreacted butenes 62.7 isobuten 4.3 ethyl tert-butyl ether 3.6 tert-butyl alcohol 3.8 ethanol 24.6 water 1.0

The following fractionation of the reaction product was carried out in a rectification column to obtain 33.0 parts of the bottom product 6 having the following composition:

% Ethanol voda3,0 motnostní ^h tert-butyl alcohol ethyl tert-butylether11,0 'moi% ^H; SAFETY unreacted butenes isobutene 93.6 16.4

From this product, 01.5 parts are recycled to the reaction as component 2 and 5.5 parts 8 are recycled.

The bottom product of the column 6 can be directly mixed with the gasoline without any problem of ^blurring .

For comparison, furthermore, the values of temperature cloud ethanol dose 1 (composition A) and the reaction product 6 (mixture B), in both cases, as 10% of an additive to a hydrocarbon product containing a mass ^{of 30% of} the aromatic ^to YC ^h tete ^{to 70%} saturated of hydrocarbons.

Haze temperature, ° C mixture A above j · ²⁰ ° C mixture B below - 20 ° C

Example 2

In a tubular reactor of FIG. 2 containing a macroporous ion exchange resin in an acid form such as Amberlyst 15, a mixture containing 34.1 parts by weight of ethanol 1 (containing 7.3% water) and 65.9 parts by weight is reacted. Olefinic fraction 2 containing ^50.7 % isobutene by weight.

The composition of the resulting mixture 3 is as follows:

% ^{H í} motnostn

non-reactive butenes 32.5 isobuten 33.4 ethanol 31.6 water 2.5

The mixture is reacted at a space velocity ^{of 1.5} · aborted per hour per liter katail · ^s at Zátor te ^pl OTE ⁶⁰ C ^whose M ^F zfeká the reaction product 4 of the following composition:

% by weight

unreacted butenes 32.5 isobuten 2 ^, 5 ethyl tert-butyl ether 45.7 tert-butyl alcohol 7.9 ethanol 10.7 water 0 ^, 7

The following fractionation of the reaction product is carried out in a rectification column to obtain 65 parts of the bottom product of the following composition:

and 67 parts of the product of Title 7 having the following composition:

% by weight ethyl tert-butyl ether 12.8 tert-butyl ether 18.4 ethanol 67.2 water 1.6 ethyl tert-butyl ether70.4 tert-butyl alcohol12.1 ethanol16.4 water1.1

The water content, based on the sum of the alcohols contained, is 3.7% by weight.

The top product of the column 6 contains 35.0 parts of an olefin fraction having the following composition:

% by weight unreacted butenes 92.9 isobutene 7.1

The cloud point of the 10% bottom 5 product with 90% (percent by weight) of the hydrocarbon fraction containing 70% by weight of saturated hydrocarbons and 30% of aromatic hydrocarbons is -12 ° C.

Example 3

In the tubular reactor of FIG. 2 containing a macroporous ion exchange resin in an acid form such as Amberlyst 15, a mixture comprising 34.2 parts by weight of ethanol containing 7.8% by weight of water, 1 and 0.5 parts by weight is reacted. olefinic fraction 2 containing 48.2% by weight of isobutene.

The resulting mixture 3 has the following composition:

% non-reactive butenes34.1 isobutene31.7 ethanol31.5 water2.7

The mixture is allowed to react at 60 [deg.] C / hr at 60 [deg.] C to provide reaction product 4 having the following composition:

% by weight

unreacted butenes 34.1 isobuten 22.9 ethyl tert-butyl ether 5.5 tert-butyl alcohol 7.9 ethanol 28.9 water 0.7

The following fractionation of the reaction product is carried out in a rectification column to obtain 43 parts of the bottom product of the following composition:

wherein the water content is based on the sum of the alcohols contained and is 1.8% by weight.

The product of Title 6 is composed of 57.0 parts of an olefin fraction having the following composition:

% by weight unreacted butenes 59.8 isobutene 40.2

The cloud point of a mixture of 10% by weight of the bottom 5 product with a 90% by weight hydrocarbon fraction containing 70% by weight of saturated hydrocarbons and 30% by weight of aromatic hydrocarbons is below -20 ° C.

Example 4

In the tubular reactor of Figure 2 containing a macroporous ion exchange resin in acid form, such as Amberlyst 15, a mixture containing 31.5 parts by weight of ethanol containing 7.5% by weight of water, 1 and 68.5 parts of olefinic fraction 2 is reacted. containing 50,8% by weight of isobutane.

The composition of the resulting mixture 3 is as follows:

% by weight

non-reactive butenes 33.7 isobuten 34.8 ethanol 29.1 water 2.4

The mixture is allowed to react at 60 ° C / hour at a space velocity of 20 liters per liter of catalyst to obtain the following reaction product 4 of the following composition:

% by weight

unreacted butenes 33.7 isobuten 25.7 ethyl tert-butyl ether 6.5 tert-butyl alcohol 7.2 ethanol 26.2 water 0.7

The following fractionation of the reaction product is carried out in a rectification column to obtain 40.6 parts by weight of the product from bottom 5 of the following composition:

The product of head 6 consists of 47.7 parts olefmové ^{f h} oto Response system that downloads% ^{h ENGINE} SAFETY ^weight% of ethyl tert-butylether16,0 tert butylalkohol17,7 ettanol ⁶⁴ water

With a water content expressed on the amount contained alkohota motnostně 2 ^{hr, 0} ° / o.

The product of Title ⁶ consists of ^59.4 parts olefin fraction of the following composition:

% unreacted ^b utey ^y 56.7 isobutene 43.3

Example

· In the tube reactor of FIG. 2, containing a macroporous ion exchange resin in acid form, such as Amerlyst 15, is reacted with a mixture consisting of 31.5 parts by weight of ethanol containing 1 weight% ^{of 7.5} and ^68.5 in ^{dy says} lu · olefinoivé fraction containing 2 weight ^{of 50,} 8% isobutene.

The composition of the resulting mixture 3 is as follows:

% by weight of non-reactive butenes33.7 isobutene34.8 ethanol29.1 water2.4

This mixture is reacted at a space ^E r ^{y l} ch Osti ²⁰ htrů Htr of catalyst per hour at 70 ° C to obtain a reaction product 4 of the following composition:

% by weight unreacted butyles ^y 33.7 isobutene14.0 ethyl eerc.-Uut ^y leeher27.3 tore-butyl-alcohol8.1 ethanol16.5 water0.4

The following fractionation of the reaction product is carried out in a rectification column to give 52.3 parts of product from bottom 5 of the following composition:

% ^H moenostУ ^diethyl terephthalic butylether52,2 tert lDutylalkohol etoanol voda0,8 unreacted buteny70,6 isobuten29,4

Example 6

In the tubular reactor of Fig. 2 containing a macroporous ion exchange resin in an acid form such as Amberlyst 15, a mixture consisting of 31.5 parts by weight of ethanol 1 containing 7.5% by weight of water and 6% by weight of 5 parts is reacted. olefinic fractions 2 containing 2-olefin; About 50.8 / ₀ by weight of isobutene.

The composition of the resulting mixture 3 is as follows:

% by weight non-reactive butenes33.7 isotatene ethanol29.1 water2.4

The mixture is reacted at a space velocity of 20 liters per liter of catalyst per ^h o ^{d p} te yne at ⁸⁰ ° C for Tata, ^No. COMES ^z to obtain ^and 4 following the reaction product of the following composition:

% ^ otaostrn unreacted butenes33,7 isobutene9,0 ethyl tert-butylether37,1 tert-butylalkole · 7,2 ethanol12,4 water0,4

Subsequent fractionation of the reaction product was carried out in a rectification column to give 57.3. product part of dha 5 with the following composition:

Hmotnostrn% ethyl tert-butylether64,7 tert butylalkohol12,6 ethanol21,6 voda1,1 water content, based on the total amount contained alcohol, 3 ^weight, 1%.

The top product of column 6 consists of 42.7 parts olefin fraction of the following composition:

% ^Unreacted hmotmosty buteyy 7δ 9 isobutene 21.1

The water content with respect to the amount ^of alcohol contained is 1.7 wt ° / o.

Claims (2)

OBJECT OF THE INVENTION 1. A process for the preparation of alcohols having 2-4 carbon atoms in the quality of ^P ^ e ^b OTR No ^P ro ^{d BC} Adding of petrol from a mixture of these alcohols oteahujírn and water characterized in that such water mixture is treated with isobutene in the presence of ion exchange resins of acidic character as acid catalyst, at a temperature of 40 to 90 ° C and at a space velocity of 5 to 25 liters of feed per liter of catalyst per hour. 2. The process according to claim 1, wherein the acidic ion exchange resin comprises sulfone groups - SO2H.