Integrated process for the preparation of compounds useful as fuel components

Abstract

The invention relates to an integrated process for the production of fuel components starting from materials of a biological origin which comprises: (A) transformation of glycerine into an alkoxy-propanediol having formula ROCH.sub.2CHOHCH.sub.2OH, wherein R is a linear or branched C.sub.1-C.sub.8 alkyl, (B) transformation of glycerine into 1,2-propanediol CH.sub.3CHOHCH.sub.2OH, (C) dehydration of the 1,2-propanediol obtained in (B) to propionic aldehyde, (D) reaction of part of the propionic aldehyde obtained in (C) with the alkoxy-propanediol having formula ROCH.sub.2CHOHCH.sub.2OH obtained in (A) to give an acetal having formula (a) wherein R is a linear or branched C.sub.1-C.sub.8 alkyl, (E) transformation of part of the propionic aldehyde obtained in (C) to a propionate having formula CH.sub.3CH.sub.2COOR, wherein R is a linear or branched C.sub.1-C.sub.8 alkyl. Particular components for gasolines and/or diesel are also described.

Claims

1. An integrated process for producing fuel components from glycerine, the process comprising purifying glycerine obtained from materials of biological origin to obtain a purified glycerine having a purity of at least 98%, and: (A) transforming a stream of the purified glycerine into an alkoxy-propanediol having formula: ROCH.sub.2CHOHCH.sub.2OH, by etherification of the purified glycerine with an alcohol having formula ROH, wherein R is a C.sub.1-C.sub.8 alkyl, in the presence of an acid catalyst; (B) transforming another stream of the purified glycerine into 1,2-propanediol by reducing the purified glycerine with hydrogen in the presence of a reduction catalyst selected from the group consisting of copper chromite, a mixed chrome-zinc-copper oxide, a noble metal on coal, and a noble metal on iron oxide; (C) dehydrating the 1,2-propanediol obtained in the transforming (B), in the presence of a solid acid catalyst at a temperature ranging from 200 to 350 C. and a pressure ranging from 0.1 to 10 atmospheres, to obtain propionic aldehyde; (D) reacting part of the propionic aldehyde obtained in the dehydrating (C) with the alkoxy-propanediol obtained in the transforming (A), in the presence of an acid catalyst at a temperature ranging from 10 to 120 C. and a pressure ranging from 0.1 to 20 atmospheres, to obtain an acetal having formula (a): ##STR00003## and (E) transforming a remaining part of the propionic aldehyde obtained in the dehydrating (C) to obtain a propyl propionate, by performing a Tishchenko reaction in the presence of a solid base catalyst.

2. The process according to claim 1, wherein: R is selected from the group consisting of CH.sub.3, C.sub.2H.sub.5, C.sub.3H.sub.7, C.sub.4H.sub.9, and C.sub.5H.sub.11; and R is selected from the group consisting of CH.sub.3, C.sub.2H.sub.5, C.sub.3H.sub.7, C.sub.4H.sub.9, and C.sub.5H.sub.11.

3. The process according to claim 2, wherein R and R are each independently selected from the group consisting of ethyl, n-propyl, iso-propyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 3-methyl-1-butyl and 2-methyl-1-butyl.

4. The process according to claim 1, wherein the acid catalyst is selected from the group consisting of an acid exchange resin, an acid zeolite, a silico alumina and a supported phosphoric acid.

5. The process according to claim 1, wherein the transforming (A) is carried out at a temperature ranging from 50 to 200 C. and a pressure ranging from 1 to 20 atmospheres.

6. The process according to claim 1, wherein the transforming (B) is carried out at a temperature ranging from 100 to 300 C. under a hydrogen pressure ranging from 1 to 100 atmospheres.

7. The process according to claim 1, wherein the solid acid catalyst is selected from the group consisting of an alumina, a silico-alumina, a zeolite, cerium oxide (IV), thorium oxide and zirconia.

8. The process according to claim 1, wherein the acid catalyst in the reacting (D) is selected from the group consisting of an acid exchange resin, a zeolite and a silico alumina.

9. The process according to claim 1, wherein the solid base catalyst is selected from the group consisting of an aluminum alcoholate having formula: Al(OR).sub.3, wherein R is a linear or branched alkyl group ranging from C.sub.2 to C.sub.6, magnesium oxide, calcium oxide, strontium oxide, barium oxide, zinc oxide, a zeolite partially or fully exchanged with at least one alkaline metal, and a hydrotalcite having formula: M.sup.2+.sub.aM.sup.3+.sub.2(OH).sub.16X.nH.sub.2O, wherein M.sup.2+ is a bivalent metal cation selected from the group consisting of Mg.sup.2+, Fe.sup.2+, Ni.sup.2+, Zn.sup.2+, Cd.sup.2+ and Co.sup.2+, M.sup.3+ is a trivalent metal cation selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ga.sup.3+, Cr.sup.3+, Mn.sup.3+ and Co.sup.3+, X is an anion selected from the group consisting of CO.sub.3.sup.2, OH.sup.3 and NO.sup.3, and a is an integer ranging from 10 to 4.

10. The process according to claim 1, wherein the transforming (E) is carried out at a temperature ranging from 20 to 150 C. and a pressure ranging from 0.1 to 50 bar.

11. The process according to claim 1, wherein: the glycerine obtained from materials of biological origin is glycerine comprising impurities of salts, water and optionally methanol; and the purifying comprises: removing the salts by treating the glycerine on at least one acid exchange resin; and removing the water and optionally the methanol by fractionated distillation.

Description

EXAMPLE 1

Etherification of Glycerine with Ethanol

(1) 10 cc of commercial resin Amberlyst 36 (Rohm and Haas, catalogue number 76079-A075C3A060) are charged into a fixed-bed reactor and the reactor is brought to a temperature of 145 C. A mixture of ethanol/glycerine (purity 99%) is then fed in a molar ratio of 10/1 at a space velocity of 0.3 hours.sup.1. The glycerine/ethanol reaction mixture is analyzed by means of mass GC indicating a conversion of glycerine equal to 71.18% and a selectivity to monoethoxy-propanediol equal to 91%, with the complement to 100% consisting of 8.88% of diethoxypropanol and 0.13% of triethoxypropane. The catalytic system proves to be stable for over 5,000 hours without any variation in the conversion and selectivity. The mixture resulting from the reaction is subjected to purification by means of distillation, the monoethoxy-propanediol obtained has a purity of 99%.

EXAMPLE 2

Reduction of Glycerine to 1,2-propanediol

(2) 10 cc of cupric chromite, a commercial product of Sigma-Aldrich (catalogue number 20,931-2), are charged into a fixed-bed reactor and the reactor is heated to a temperature of 250 C. by feeding pure hydrogen for 6 hours. The feeding of pure hydrogen is then interrupted and a mixture of pure glycerine (purity 99%) and hydrogen is fed in a glycerine/hydrogen molar ratio of 1/2 in moles at 250 C. and at a space velocity of 1 hour.sup.1. The total conversion of the glycerine is obtained, with a selectivity to 1,2-propanediol equal to 98%, with the complement to 100 consisting of propanol and hydroxyacetone. The catalyst proves to be stable under the reaction conditions for over 700 hours. The 1,2-propanediol obtained is purified by distillation, obtaining a product having a purity of 99.5%.

EXAMPLE 3

Dehydration of 1,2-propanediol to Propionic Aldehyde

(3) 10 cc of ZSM-5 zeolite in acid form (Zeolyst CBV 5524G-1822-18) are charged into a fixed-bed reactor and the reactor is heated to a temperature of 300 C. The 1,2-propanediol obtained from the previous reaction is then fed at a space velocity equal to 0.5 hours.sup.1. A complete conversion of 1,2-propanediol is obtained, with a selectivity equal to 83% to propionic aldehyde, with the complement to 100 consisting of acetone and propanol.

(4) The propionic aldehyde thus obtained is purified by distillation from the other reaction products and half is destined for the reaction of Example 4 and the other half for the reaction of Example 5.

EXAMPLE 4

Synthesis of 2-ethyl-4-ethoxymethyl-1,3-dioxolane

(5) 10 cc of acid exchange resin Amberlyst 36 (Rohm and Haas, catalogue number 76079-A075C3A060) are charged into a fixed-bed reactor and a 1/1.05 mixture of monoethoxy-propanediol obtained in Example 1 and half of the propionic aldehyde obtained in Example 3 is fed at room temperature. The reaction mixture is fed at room temperature and at a space velocity equal to 5 hours.sup.1. A total conversion of the monoethoxy-propanediol fed is obtained, with a selectivity of 99% to the acetal 2-ethyl-4-ethoxymethyl-1,3-dioxolane. The acetal thus produced is then purified by distillation obtaining a product having a purity of 99%. The acetal thus obtained can be advantageously added to gasoil for the preparation of fuel compositions.

EXAMPLE 5

Transformation of Propionic Aldehyde to Propyl Propionate

(6) Half of the quantity of propionic aldehyde obtained in Example 3 (50 g) is introduced into a three-necked glass flask, equipped with a cooler and mechanical stirrer. 0.5 g of aluminium isopropylate are then added and the mixture is stirred for 30 minutes at room temperature. The reaction is interrupted and the products obtained analyzed. The conversion of propionic aldehyde proves to be equal to 99% with a selectivity of 96% to propyl propionate. The propyl propionate thus obtained is separated from the reaction mixture by means of distillation. The propyl propionate can be advantageously used as component for gasolines.