EP0204784A1 - Extenders for gasoil for automotive use - Google Patents

Abstract

A process makes it possible to prepare additives for gas oil used in motor vehicles. The present diesel fuel additives are selected from the class of dioxygenated methane derivatives having the general formula (I) in which R1 and R2, identical or different, are linear or branched alkyl groups having from 1 to 20 carbon atoms, preferably of 2 to 10 carbon atoms, or alkoxyalkyl groups of the formula R1- (OR) x-, in which R is an alkyl group containing from 2 to 6 carbon atoms, and R1 is an alkyl group containing from 1 to 20 atoms of carbon, preferably from 2 to 10 carbon atoms, x being between 1 and 10. The preparation of gas oil additives is carried out by reacting an alcohol or a mixture of alcohols with a formaldehyde in the presence of a homogeneous or heterogeneous acid catalyst in the reaction medium.

Description

Extenders for gasoil for automotive use.

The present invention relates to gasoil extenders for automotive use, and to the method for their preparation.

As it is known to those skilled in the art, in the past the quality and the quantity of medium distillates ob tainable by direct fract i onat i on of the most of crude oils have been able to satisfy the market requirements in the field of gasoils for automotive use. In that situation, low-quality products were mostly used as fluidizers for fue I oils. At present time, the situation is developing in such a way that refining activity could have difficulties in satisfying the market requirements, both as for quality and for quantity. The facts which cooperate to a greater extent to cause such trend are the following: a) Increase in diesel engines use rate: the forecasts in¬ dicate a general decrease in volumetric ratio between the demand of gasoline, and the demand of gasoil. b) Decrease in consumption of fuel oils: The reduction in consumption of fuel oi ls, caused by environmental rea- sons, in industrial and household heating, has convey¬ ed a large share of derivatives of conversion process¬ es (FCC, visbreaking, and so forth), used as fluidizers for the residues, into gasoils, contributing to satisfy the increased demand, but tending to making worse the quality of the product. c) Need of processing heavy crude oils: such crude oils su ply distillates of lower quality, require a greater re sort to conversion processes, and cause, in the overal an increase of poor-quality products. It has been surprisingly found, and this is a first object of the present invention, that gasoil extenders se¬ lected in the class of dioxygenated derivatives of methane can increase the available amounts of gasoil for automotive use, and contemporaneously improve the quality thereof. The extenders for gasoil for automotive use according to the present invention are selected in the class of di¬ oxygenated derivatives of methane, and have the general for mula

OR

1 ^

OR. wherein R. and R_, equal to or different from each other, 1 2 are straight or branched alkyl groups, having from 1 to 20, preferably from 2 to 10 carbon atoms, or alkoxyalkyl groups

1 of formula R -(0-R) -, wherein R is an alkyl group having

^X 1 from 2 to 6 carbon atoms, and R is an alkyl group having from 1 to 20, preferably from 2 to 10, carbon atoms, x be¬ ing comprised within the range of from 1 to 10.

The gasoil extenders according to the invention are to be added to gasoils in an amount comprised within the range of from 1% to 40% by volume of the volume of starting gas¬ oil, preferably of from 5% to 25% by volume.

The starting gasoils to which the gasoil extenders ac¬ cording to the invention are to be added, comprise those having a distillation range comprised within the range of from 160 to 400°C. They have typically density comprised within the range of from 0.800 to 0.880 kg/l, cetane num¬ ber comprised within the range of from 35 to 60, turbidity temperature comprised within the range of from +10°C to -25°C.

The gasoil extenders according to the present inven- tion can be used as a function of their characteristics to the purpose of:

1) increasing the volume of gasoil without impairing its quali ty

2) improving the properties of a gasoil of poor quality from the viewpoint of cetane number, of stability, of flowing characteristics and of low-temperature filter- ability characteristics.

A second object of the invention is the method for the production of the gasoil extenders as previously dis- c losed.

The method according to the present invention com¬ prises reacting in an aqueous medium an alcohol or a mix¬ ture of alcohols and/or their g lycol=-ethers with formal¬ dehyde or substances releasing formaldehyde under the reac tion conditions, in the presence of an acidic catalyst, either homogeneous or heterogeneous in the reaction medium, and fractionating the end reaction mixture, separating the formal or the formals obtained.

Alcohols are aliphatic, straight or branched, with a number of carbon atoms comprised within the range of from 1 to 20, preferably of from 2 to 10.

The glycols have a number of carbon atoms comprised within the range of from 2 to 6.

As the catalyst, sulphuric acid, ch lorosu Iphoni c ac¬ id, toluenesu Iphoni c acid, phosphoric acid can be used, or an acidic resin can be used, selected among the following ones :

Amberlyst 15-Rohm and Haas; Duolite C26-Di aprosi n; Lewatit SPC-Bayer; Kastel C 300 Ausimont.

The reaction conditions are, as for the temperature, from room temperature up to reaction mixture boiling tem¬ perature.

According to a preferred embodiment, water present or being formed during the reaction is continuously removed during the reaction course by azeotropic distillation, in particular by means of the addition of a hydrocarbon com¬ ponent suitable to form azeotropes, or by rectificat on in distillation column.

Examples shall now be given, to the purpose of illus¬ trating the invention, it being intended that it is not to b considered as limited to them or by them. In an equipment, constituted by a flask mechanically stirred, and bearing atop an equipment for the separation and removal of distilled water, 60 g of 1 ,3,5-trioxy eth- ylene, equivalent to 2 mol of formaldehyde, 370 g (5 mol) of isobutyl alcohol, 20 g (98 meqH ) of a cationic resin in acidic form (Amberlyst 15) and 100 ml of benzene are charged. The reaction mass is heated to boiling tempera¬ ture and, when all water formed in the reaction has been removed, the resin is filtered off, the filtrate is wash¬ ed with aqueous NaHCO (to remove the last traces of a- cidity), and is fractionated on tray column. A product is obtained with (G.C.) purity greater than 99%, and with yields close to theoretical value.

Examg_ιle_ι_2 With the same equipment and modalities as of Example 1, 60 g of 1 ,3,5-trioxane, 380 g (5 mol) of monoethylene- glycol-mono ethyl-ether, 2.5 g of concentrated H_S0, (50

2 4 eqH ), and 100 ml of benzene are charged. The reaction mixture is heated to boiling temperature and, when the reaction is ended, the mass is washed with aqueous NaHCO. to neutralize all H_S0., and is fractionated on tray col-

2 umn. A product is obtained with purity 99% and with yield close to stoi chi ometri c value.

Examg_ιle_3

With the same equipment and modalities as of fore¬ going Examples, 150 g of a solution at 40% by weight of formaldehyde in water (equivalent to 2 mol of aldehyde), 360 g of n-propyl alcohol (6 mol), 20 g of Amberlyst 15 and 100 ml of cyclohexane are charged. The reaction mix¬ ture is heated to refluxing temperature, and water con¬ tained in formaldehyde and that formed during the reac¬ tion is azeot ropi cal ly distilled. The residual organic phase is fi ltered, neutralized and rectified.

A product is obtained with purity 99% and yield greater than 90%.

Examg_le_4

With the same modalities as of foregoing examples, 60 g of parafor a Idehyde (2 mol of aldehyde), 440 g of n- a yl alcohol (5 mol), 20 g of Amberlyst 15 and 100 ml of benzene are charged. The reaction mixture is heated to re- fluxing temperature, and reaction water is removed; the resin is fi ltered off, the filtrate is neutralized and fractionated on tray column. The product obtained has a purity of 99%, and the yield is close to theoretical val¬ ue.

Exa g lle_5

With the same modalities as of foregoing Examples, 60 g of 1,3,5-trioxymethylene (equivalent to 2 mol of for¬ maldehyde), 370 g (5 mol in the overall) of a mixture of isobutyl alcohol 80% and n.butyl alcohol 20%, 20 g of Amber- lyst 15 and 100 ml of toluene are charged. The reaction mixture is heated to boiling temperature, and reaction water is azeotropi ca I ly distilled off. At the end of the reaction, the resulting reaction mixture is washed with a- queous NaHCO,, and the product is rectified. The three pos sible products (di i sobuty1-, i sobutyl-n-but I- and di-n- butyl-formal) are combined in one single fraction. The ra¬ tio of alkyl chains in this fraction is practically iden¬ tical to that of charged alcohols. The overall yield, cal¬ culated relatively to formaldehyde, is close to theoretic¬ al value.

By procedures similar to those as reported in Example 1, formals have been produced by starting, instead of from isobutanol (iC.), from n-propanol (nC_⁾, isopropanol (iC_), 4 _> 3 n-butanol (nC_#), tert.butanol (tC.), n-pentanol (nC_), and 4 4 5 isopentanol (iC ). Yields and purity levels have been iden tical to those obtained with isobutanol.

By the same procedure as reported in Example 1, formals have been produced by starting from mixtures 80% i sobutanol-20% n.butanol (80/20 iso/nor C.), 60% isobutan-

4 ol-40% n.butanol (60/40 iso/nor C.), 80% sec .butanol-20% n.butanol (80/20 sec/nor C,), and 60% sec .butano 1-40% n.-

4 butanol (60/40 sec/nor C.). Yields and purity levels are

4 una Ltered.

Example 2 has been finally repeated by replacing meth yl Cellosolve with n-butyl Cellosolve, ethyl Cellosolve, and 80/20 and 60/40 isoC_ and nC mixtures, formals being obtained with yields and purity levels as of Example 2.

All formals produced have been checked as for their characteristics, and in mixture with a gasoil having cetane number 40. In Table 1 the values found are reported (Exam- pies 6 - 22).

TABLE 1 - CHEMICAL-PHYSICAL AND AUTOMOTIVE PROPERTIES OF F

Starting alcohol Freez. d(20°C) Boiling Blen point g/cc point ceta (°C) °C (mmHg) ber

Ex. 6 nC. -97.3 .833 146(760) Ex. 7 iC. <-50 .818 120(760) Ex. 8 nC. -60 .838 181(760)

4 Ex. <-100 .825 163(760)

^{9 iC}4 Ex. 10 tc. -46 .828 78(96)

4 Ex. 11 nC-. -47 .841 220(760) Ex. 12 iC₅ < -50 .834 211(760) Ex . 13 80/20 iso/nor C, <-50 .825 163-181(760)

4 Ex. 14 60/40 iso/nor C, <-50 .826 163-181(760)

4 Ex. 15 80/20 sec/nor C. <-50 .836 159-181(760)

4 Ex. 16 60/40 sec/nor C. <-50 .836 159-181(760)

4 Ex. 17 methyl Cellosolve <r50 .992 202(760) Ex. 18 n .butyICel losolve -47 .903 270(760) Ex. 19 ethyl Cellosolve \-50 .951 222(760) Ex. 20 80/20 isoC /nC <-50 .834 146-211(760) Ex. 21 60/40 isoC /nC -50 .834 146-211(760)

In Table 2 the turbidity points are reported of some gasoi l-forma I mixtures.

Formals are indicated by the starting alcohol.

TABLE 2 TURBIDITY POINT OF GASOIL/ FORMAL BLENDS 80/20 V0L/V0L

Ii-£_2i_.iJ _E2ioiz_--_.

Base gasoi I +5 nC . /gasoi I +4

4 isoC./gasoil +3

4 secC, /gasoi I +4

4 In Table 3 the characteristics of low-temperature fi Iterabi lity (CFPP) are reported of some gasoi l/forma I blends.

TABLE 3 CFPP OF GASOIL/FORMAL BLENDS 80/20 VOL/VOL

C£EE_.___C Base gasoi I +3 nC . /Gasoi I 0 4 nC_/Gasoi I 0 methyl Cel losolve/gasoi I +2 n.butyl Cel losolve/Gasoi I +2

CFPP = Low-temperature fi Iterabi lity characteristics.

Claims

1. Extenders for gasoil for automotive use, charac¬ terized in that they are selected from the class of di¬ oxygenated derivatives of methane.

2. Gasoil extenders according to claim 1, characterized in that the dioxygenated derivatives of methane have the ge¬ neral formula

C

wherein R_ and R_, equal to or different from each other,

1 2 are straight or branched alkyl groups, having from 1 to 20

1 carbon atoms, or alkoxyalkyl groups of formula R -(0-R) , wherein R is an alkyl group having from 2 to 6 carbon at-

1 oms, and R is an alkyl group containing from 1 to 20 car- bon atoms, x being comprised within the range of from 1 to 10.

3. Gasoil extenders according to claim 2, charac¬ terized in that the straight or branched alkyl groups have a number of carbon atoms comprised within the range of , from 2 to 10.

4. Gasoil extenders according to claim 2, character-

1 ized in that R has a number of carbon atoms comprised with¬ in the range of from 2 to 10.

5. Gasoil extenders according to foregoing claims, characterized in that they are added to the gasoils in an amount by volume compr sed within the range of from 1% to 40% of gasoil volume.

6. Gasoil extenders according to claim 5, character¬ ized in that they are added to gasoils in an amount by vol ume comprised within the range of from 5% to 25% of gas¬ oi I volume.

7. Method for the production of gasoil extenders ac¬ cording to foregoing claims, characterized in that it com prises the reacting in an aqueous medium of an alcohol or of a mixture of alcohols and/or their glyco l-ethers with for¬ maldehyde or substances liberating formaldehyde, in the presence of an acidic catalyst, and the fractionating of the end reaction mixture, separating the formal or the formals obtained.

8. Method according to claim 7, characterized in that alcohols have a number of carbon atoms comprised within the range of from 1 to 20.

9. Method according to claim 8, characterized in that alcohols have a number of carbon atoms comprised within the range of from 2 to 10.

10. Method according to claim 7, characterized in that the glycols have a number of carbon atoms comprised within the range of from 2 to 6.

11. Method according to claim 7, characterized in that the acidic catalyst is selected among sulphuric acid, ch lorosu Iphoni c acid, to luenesu Iphoni c acid.

12. Method according to claim 7, characterized in that the acidic catalyst is an acidic resin.

13. Method according to claim 12, characterized in that the acidic resin is selected among Amberlyst 15, Duolite C26-Di aprosin, Lewatit SPC-Bayer, Kastel C 300 Ausimont .

14. Method according to claim 7, characterized in that the reaction temperature varies within the range of from room temperature to the boiling temperature of the reacti on mi xture .

15. Method according to claim 7, characterized in that water is continuously removed from reaction mixture by azeotropic distillation.