EP0495941A1

EP0495941A1 - Process to prevent water solubilization of alcohols, on their own or in a mixture with hydrocarbons, and additives for such purposes

Info

Publication number: EP0495941A1
Application number: EP91913064A
Authority: EP
Inventors: Maria Gabriella Scopelliti
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-07-24
Filing date: 1991-07-22
Publication date: 1992-07-29
Also published as: WO1992001770A1; IT9018708A0; IT9018708A1; IT1243220B

Abstract

Le procédé décrit empêche la solubilisation dans l'eau d'alcools, à l'état pur ou mélangés à des hydrocarbures, grâce à la présence d'inhibiteurs de formation de liaisons hydrogéne dans la phase alcool et/ou dans la phase hydrocarbure et/ou dans la phase eau, ce qui permet d'exploiter la teneur en octane et les faibles émissions des alcools, pour formuler ainsi un nouveau type d'essence sans plomb.The described method prevents the solubilization in water of alcohols, in the pure state or mixed with hydrocarbons, thanks to the presence of inhibitors of hydrogen bond formation in the alcohol phase and / or in the hydrocarbon phase and / or in the water phase, which makes it possible to exploit the octane content and the low emissions of alcohols, to formulate a new type of unleaded petrol.

Description

"Process to prevent water solubilization of alcohols, on their own or in a mixture with hydro= carbons, and additives for such purposes."

The invention concerns a process to prevent water solubilization of alcohols, on their own or in a mixture with hydrocarbons to exploit the octa= nicity and the low emissions of alcohols and thus formulate a new type of unleaded gasoline, precluding or limiting the possibility of the water to form hydrogen bonds with the -OH groups of alcohols.

10

In the use of alcohols, or of their mixtures with hydrocarbons (HC), as fuel for autovehiclβs , a great problem is constituted by the fact that alcohols inferior to butyl alcohol, usually used

-; ~~ for this purpose, are totally water-soluble.

Such inconvenience is greatly felt especially when alcohols are in a mixture with HC as, if the mixture alcohols/HC already formulated came <_0 into contact with water, the alcohols would become soluble and the mixture would no longer have the initial characteristics, thus resulting out of specification.

25 Furthermore, since the water is in turn soluble in alcohol the part of the water that has become soluble in the alcohol/HC mixture tends to form a single phase . In certain conditions, there is however a separation between a mixed phase alcohols + water and a hydrocarbon phase.

The phase alcohols + water is heavier and goes to the bottom of the tank of the automobile; once intaken this causes the engine to stop, damaging it.

Therefore the necessity to prevent solubilization of alcohols in the water becomes evident.

In this present condition, research has moved towards the use of blending components (co-solvents) to be added to gasoline, and thus in quantity of the order of 5-20%, in order to increase the water tolerance of gasoline (that is to say the quantity of water that the gasoline can tolerate without having a phase-separation in certain conditions). For example in the addition of 10% toluene at 20°C there is a 0,4 - 0,5% water tolerance .

The present invention refers to a process and to additives to be used in sparing quantities, to allow the use of alcohols, on their own or in blending with HC, without having the above mentioned inconvenience. This will allow the exploitation of the octanicity and low emissions of alcohols in order to formulate alcohol fuels .

It is known that the principle inconvenience in using alcohols as fuel, on their own or in a HC mixture, is the effect of the water. The alcohols and the HC are completely mixable at room temperature. While in the presence of alcohols sparing quantities of water will dissolve, there will be a total phase-separation if these quan= titles exceeded.

The heavier layer water + alcohol will go to the bottom and will send the fuel out of specifi= cation, if this occurs in the storage tank or else it will damage the engine of the automobile, if it is intaken by it.

Water solubilization of alcohols occurs by formation of hydrogen bonds with it.

Such solubilization will thus be inhibited if the water finds something to bind with prefe= rentiallv.

In particular the solubilization will be inhibited if in the water there will be present a compound that will form a hydrogen bond with it, stronger than that of water-alcohol.

Furthermore the non-solubilization will be accen= tuated, or else it will be able to use lesser quantities of above mentioned compound (that forms with the water a stronger hydrogen bond than that of water-alcohol), if the water will be engaged in the dissolution of an electrolyte. In that case in fact there is an orientation of the dipoles of the water towards the cation of the electrolyte with the formation of electro= static bonds. This will greatly disturb the possi= bility of the formation of a hydrogen bond both in energetic and in steric terms.

In fact the formation of the hydrogen bond will have to compete with the breaking of the electro= static bond; furthermore, since the hydrogen bond is greatly directional, the hydrogen atoms of the alcohols will not find the oxygen atoms of the water available to the bond, engaged as they are around the cation of the electrolyte.

The above mentioned effects can occur, separately treating, both the alcohols on their own or in a mixture of HC and water, which will go in the storage tank (either to the production or to the distribution).

To inhibit the hydrocarbon and/or alcohol phase one can use phenol.

This in fact is soluble both in alcohol and in HC; it is furthermore water soluble (8,2 g/100 g of water at 15°C, totally soluble at 65,3°C), where it forms a stronger hydrogen bond than that water-alcohol.

Thanks to its characteristics it can be directly injected in an alcohol and/or HC phase functioning as an inhibitor of solubilization of alcohols in case they should, on their own or in a mixture of HC come into contact with water.

Furthermore the phenol will act at low temperatures in which the water tolerance is lower than the mixtures alcohols/HC.

To inject a more easily handable product, the phenol can be dissolved in an opportune solvent that notably lowers the freezing point.

The insolubility in water can be the characteristic of the solvent.

In certain exemplifying variants, the solvents that increase the water tolerance of the alcohols can be alcohols superior to butyl alcohol, benzene, toluene, xylene, 4 methylpentane 2-1, cumene , hexane. They can furthermore be considered compounds of synergic action as the organic acetates (of methyl, of ethyl, of isoamyl, of t-butyl, etc.), the methylcyclopentane, the triethylamine , etc.

These synergistic compounds can also be used on their own or in a mixture, as formation inhi= bitors of hydrogen bond as an alternative to phenol and/or aniline and/or N-methylaniline .

Alternately to the phenol, or in some cases together with it, the aniline can be used, or, better still, the N-methylaniline. Such compounds have an effect that is comparable to phenol as regards to the alcoholic phase and/or hydrocarbon phase mentioned. Furthermore the N-methylaniline has a low freezing point (-57°C) therefore it can be used together with phenol both as a solvent and as a compound of synergic action. The addition to phenol of aniline and/or of N-methylaniline has furthermore the advantage of diminishing the copper corrosion (ASTM D 130) of gasoline.

The organic acetates diminish copper corrosion of gasoline too. Likewise other phenolic or ammino compounds can be used with particular reference to substituted anilines. The additive formulated as will be described, besides preventing alcohol solubilization has some intrinsic octanic properties. Furthermore, given the anti-oxidant properties of the phenolic and/or anilinic compounds the oxidation stability (induction period) of the fuel will improve notably.

As mentioned already, in order to increase the non-solubilization of alcohols or at least in order to diminish the quantity of phenolic, anilinic or organic acetates additive to be used, it is also necessary to treat the water at the bottom of the storage tank with an electrolyte. With this aim it is possible to use for the production, as illustrative but not limitative examples, the sodium chloride and/or potassium chloride.

Such compounds have the advantage to be little soluble in alcohol and thus to "protect" the fuel from contacts with water along the chain of distribution in case there should be any de= ficiencies in the inhibitions of the water (to be carried out as the following describes). NaCl or KC1 , dissolved in the fuel by means of alcohol, would in fact become a solution in water if they came into contact with water that was not very inhibited, thus contributing a limited solubilization of the alcohol in a water phase. Such a solution would furthermore have the advantage of "inhibiting" eventual water carry-over present in the nydrocarbon compound of blending.

Instead, in service stations, in which the suc= cessive step of the fuel is its use in automo= biles, the electrolyte will have to be insoluble in alcohol and/or hydrocarbons. In such case other electrolytes have to be used, illustrative examples that are not limitative of these are:

NaHCO , Na CO , Na SO , NaAlO , KHSO , K CO , CaCO , 3 2 3 2 4 2 3 2 3 3

MnSO , FeSO , FeSO (NH ) SO , Ca(HC0 ) , (NH ) CO , 4 4 4 4 2 4 2 2 4 2 3

NH HCO Al (SO ) , 4 3 2 4 3

Alternatively, this type of electrolytes can also be used in the storage tank at the production site. Since a certain amount of water is always present in the storage tanks, it is necessary that prior to the storage of the alcohols, or of their mixtures with HC , the tank shoulα be emptied and totally drained of water that is p r e s e n t .

In another vessel, equipped with mixer and heatable, a saturated solution will be prepared or better still an over-saturated in NaCl and/or KC1 (or in other electrolytes soluble or insoluble in alcohol) that will be injected in the tank by means of the draining tube.

Alternatively sea-water can be used. The tank will thus be ready to receive alcohols, on their own or with HC , treated as already described.

Periodically the titre of the water solution at the bottom will be analysed in order to determine if it is necessary to add further electrolyte (solid or as an over-saturated solution) directly into the tank or by repeating the operation.

The maintainance of the saturation of the solution is sufficient to face the eventual water carry¬ over present in the blending components.

The same process can take place in the tanks at service stations upon discharging of the water present; in this case it will be necessary to use an electrolyte insoluble _,n alcohol. Using the process and the above mentioned additives, a retention of alcohols in HC phase, in the order of 95-100% is obtained. For example, additivising 0,5% of the inhibitor in alcohol/HC phase (phenol !_> and/or N-methylaniline and/or organic acetate), the retention of methanol, ethanol , isopropanol in HC phase is: 96.6, 99.6, 99.8% respectively (adding 0,5% of water over-saturated in NaCl).

The tests have been carried out with 10% of alcohol in HC phase; after agitation of 15" and separation of the phases for 3¹ , the quantity of alcohol in the water phase is analysed chromatographi= cally: owing to a difference the retention of alcohol in HC phase is obtained. The retention of ethanol (10% in unleaded gasoline) adding 10% of over-saturated water in NaCl and 0,5% of hydrogen bond inhibitor is resulted in 90% approximately. Without an inhibitor in a HC/alcohol phase, and with 10% distilled water the retention of ethanol (10% in unleaded gasoline) in HC phase is of 25% approximately.

The dosage of the inhibitor in alcohol/HC phase is carried out on the ground of the water present in the tank, maintaining themselves conservative to keep count of eventual water carry-over in the blending components. The fuel maintains its retentive properties with regards to the alcohols in case it should come into contact with water that has been totally untreated.

In this case, obviously, the retention is inferior to that one obtained precedently.

Claims

Ciairas

1) Process to prevent water solubilization of alcohols, on their own or in a mixture with hydrocarbons, in order to exploit the octanicity and the low emissions of the alcohols and thus formulate alcohol fuels, precluding or limiting the water the possibility to form hydrogen bonds with the -OH groups of the alcohols, characterised by the presence of an inhibitor of formation of hydrogen bonds in alcohol and/or hydrocarbon phase as the phenol, the aniline, the N-methyl= aniline, organic acetates, mixtures of phenol/ani= line or phenol/N—methylaniline in whatever pro= portion.

2) Process according to claim 1, characterised by the fact that the inhibitor is constituted by one or more phenolic compounds more acid than phenol and/or ammino compounds, especially the substituted anilines.

3) Process according to claims 1 and 2, characterised by the fact that the solvent of the inhibitor is constituted by an insoluble compound in water at a low freezing point, as an alcohol superior to butyl alcohol or an hydrocarbon of the type of benzene, toluene, xylene , cumene , 4-methylperitane 2-1. 4) Process according to claims 1-3, characterised by the fact that the solvent is constituted by a compound of synergic action in the prevention of the formation of hydrogen bonds, as organic acetates (of methyl, of ethyl, of butyl, of amile etc.), the methylcyclopentane , the triethylamine , the aniline and substituted anilines, such compounds able to be used on their own or their mixtures, as inhibitors. 0

5) Process according to claim 1, characterised by the addition, in the containing tank of alcohols, on their own or in mixtures of hydrocarbons, of inhibited water to the saturation or the over- , saturation, with one or more compounds of electrolitic type, which prevent the possibility of formation of hydrogen bonds.

6) Process according to claims 1-5, characterised 0 by the addition, directly in the containing tank of alcohols, on their own or in a mixture with hydrocarbons, of one or more inhibitors compounds of the possibility of formation of hydrogen bonds of electrolitic types, as NaCl and/or KC1 or ^F others, soluble in alcohol.

7) Process according to claim 1, characterised by the addition of sea-water, in the containing tank of alcohols, on their own or in a mixture with hydrocarbons.

8) Process according to claims 1-6, characterised by the fact that the electrolytes are insoluble in alcohol, as Na2C03 or NaHC03.