Mixed oxides of transition metals, hydrotreatment catalysts obtained therefrom, and preparation process comprising sol-gel processes

Abstract

New sulfided metal catalysts are described, containing a metal X selected from Ni, Co and mixtures thereof, a metal Y selected from Mo, W and mixtures thereof, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by the sulfidation of mixed oxide precursors, also new, having general formula (A)
X.sub.aY.sub.bZ.sub.cO.sub.d.pC(A) possibly shaped without a binder, or by sulfidation of mixed oxides having formula (A), in shaped form with a binder, wherein X is selected from Ni, Co and mixtures thereof, Y is selected from Mo, W and mixtures thereof, Z is selected from Si, Al and mixtures thereof, O is oxygen, C is selected from: a nitrogenated compound N, an organic residue deriving from the partial calcination of the nitrogenated compound N, said nitrogenated compound N, when present, being selected from: a) an alkyl ammonium hydroxide having formula (I)
R.sup.IR.sup.IIR.sup.IIIR.sup.IVNOH(I) wherein the groups R.sup.IR.sup.IV, the same or different, are aliphatic groups containing from 1 to 7 carbon atoms, b) an amine having formula (II)
R.sup.1R.sup.2R.sup.3N(II) wherein R.sup.1 is a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, and R.sup.2 and R.sup.3, the same or different, are selected from H and a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, said alkyl being equal to or different from R.sup.1, a, b, c, d are the number of moles of the elements X, Y, Z, O, respectively, p is the weight percentage of C with respect to the total weight of the precursor having formula (A), a, b, c, d are higher than 0 a/b is higher than or equal to 0.3 and lower than or equal to 2, (a+b)/c is higher than or equal to 0.3 and lower than or equal to 10, preferably varying from 0.8 to 10 d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al and p is higher than or equal to 0 and lower than or equal to 40%. Said catalysts can be used as hydrotreating catalysts.

Claims

1. A sol-gel process for preparing a mixed oxide of formula (A), comprising: preparing a hydroalcohol solution/suspension comprising at least one soluble or partially soluble source of at least one element X, at least one soluble or partially soluble source of at least one element Y, at least one soluble source, which can be hydrolyzed or dispersed, of at least one element Z and a nitrogenated compound N selected from: a) an alkyl ammonium hydroxide of formula (I)
R.sup.IR.sup.IIR.sup.IIIR.sup.IVNOH(I) wherein R.sup.I, R.sup.II, R.sup.III and R.sup.IV are the same or different and are aliphatic groups containing from 1 to 7 carbon atoms, b) an amine of formula (II)
R.sup.1R.sup.2R.sup.3N(II) wherein R.sup.1 is a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, and R.sup.2 and R.sup.3 are the same or different and are selected from H and a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, said alkyl being equal to, or different from, R.sup.1; wherein the molar ratio N/(X+Y) is greater than 0.1 and less than, or equal to 1, obtaining the formation of a gel, maintaining the gel under stirring, maintaining the gel under static conditions, drying the gel prepared in the previous step, obtaining the mixed oxide precursor of formula (A2)
X.sub.aY.sub.bZ.sub.cO.sub.d.pC(A2) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is selected from Si, Al or a mixture thereof, O is oxygen, C is a nitrogenated compound N selected from the nitrogenated compounds mentioned above, having formula (I) or (II), a, b, c, d are the number of moles of the elements X, Y, Z and O, respectively, p is the weight percentage of C with respect to the total weight of the compound having formula (A2) a, b, c, d are greater than 0 a/b is greater than or equal to 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to 0.8 and less than or equal to 10 when Z is Si or a mixture of Si and Al, but is greater than or equal to 0.3 and less than or equal to 10 when Z is Al, d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al and p is greater than 0 and less than or equal to 40%, optionally subjecting the compound of formula (A2) resulting from the previous step, to partial or total calcination, respectively obtaining a compound having the same formula (A2) wherein C is an organic residue deriving from the calcination of the nitrogenated compound, or a mixed oxide of formula (A1)
X.sub.aY.sub.bZ.sub.cO.sub.d(A1) wherein X, Y, Z, O, a, b, c, d correspond to those of the previous formula (A2); and wherein said mixed oxide of formula (A) has the formula:
X.sub.aY.sub.bZ.sub.cO.sub.d.pC(A) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is selected from Si, Al or a mixture thereof, O is oxygen C is selected from: a nitrogenated compound N, an organic residue deriving from the nitrogenated compound N by partial calcination, wherein said nitrogenated compound N is selected from: a) an alkyl ammonium hydroxide of the formula (I)
R.sup.IR.sup.IIR.sup.IIIR.sup.IVNOH(I) wherein the groups R.sup.I, R.sup.II, R.sup.III and R.sup.IV are the same or different and are aliphatic groups containing from 1 to 7 carbon atoms, b) an amine having formula (II)
R.sup.1R.sup.2R.sup.3N(II) wherein R.sup.1 is a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, and R.sup.2 and R.sup.3 are the same or different and are selected from H and a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, said alkyl being equal to or different from R.sup.1 a, b, c, d are the number of moles of the elements X, Y, Z, O, respectively, p is the weight percentage of C with respect to the total weight of the compound having formula (A), a, b, c, d are greater than 0 a/b is greater than or equal to 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to 0.8 and less than or equal to 10 when Z is Si or a mixture of Si and Al, but is greater than or equal to 0.3 and less than or equal to 10 when Z is Al, d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al and p is greater than or equal to 0 and less than or equal to 40%.

2. The process according to claim 1, wherein, when Z is silicon, the corresponding soluble compounds, which can be dispersed or hydrolyzed, are colloidal silica, fumed silica and tetraalkyl ortho silicates wherein the alkyl group contains from 1 to 4 carbon atoms.

3. The process according to claim 1, wherein, when Z is aluminium, the corresponding soluble compound is aluminium lactate and the corresponding dispersible or hydrolyzable compounds are dispersible aluminas, monohydrated aluminas AlOOH, trihydrated aluminas Al(OH).sub.3, aluminium oxide, aluminium trialkoxides wherein the alkyl is linear or branched and can contain from 2 to 5 carbon atoms.

4. The process according to claim 1, wherein, in the last step, the total calcination is effected at a temperature of at least 450 C.

5. The process according to claim 4, wherein the total calcination is effected at a temperature higher than or equal to 450 C. and lower than or equal to 600 C.

6. The process according to claim 1, wherein the calcination is effected partially and at a temperature lower than 450 C.

7. The process according to claim 6, wherein the partial calcination is effected at a temperature ranging from 200 to 400 C.

8. The process according to claim 1, comprising the following steps: 1) an aqueous solution (a) is prepared of at least one soluble or partially soluble source of at least one metal Y, and alkyl ammonium hydroxide, of formula
R.sup.IR.sup.IIR.sup.IIIR.sup.IVNOH(I) wherein the groups R.sup.I-R.sup.IV are the same or different and are aliphatic groups containing from 1 to 7 carbon atoms, is added to this solution, 2) a solution/suspension (b) in alcohol is prepared, of a hydrolyzable or dispersible soluble compound of the element Z and of at least a soluble or partially soluble source of at least one metal X; 3) the solution (a) and the solution/dispersion (b) are mixed, obtaining the formation of a gel; 4) this gel is maintained under stirring, 5) the gel is maintained under static conditions, 6) the gel resulting from step (5) is dried, obtaining a mixed oxide of formula (A2)
X.sub.aY.sub.bZ.sub.cO.sub.d.pC(A2) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is selected from Si, Al or a mixture thereof, O is oxygen, C is a nitrogenated compound of formula (I), a, b, c, d are the number of moles of the elements X, Y, Z and O, respectively, p is the weight percentage of C with respect to the total weight of the compound of formula (A2) a, b, c, d are greater than 0 a/b is greater than or equal to 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to 0.8 and less than or equal to 10, d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al p is greater than 0 and less than or equal to 40%, 7) the product obtained from step (6) is optionally subjected to partial or total calcination, obtaining, respectively, a compound having the same formula (A2) wherein C is an organic residue deriving from the calcination of the nitrogenated compound, or a mixed oxide of formula (A1):
X.sub.aY.sub.bZ.sub.cO.sub.d(A1) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is selected from Si, Al or a mixture thereof, O is oxygen a, b, c, d are the number of moles of the elements X, Y, Z, O, respectively and are greater than 0 a/b is greater than or equal to 0.3 and less or equal to 2, (a+b)/c is greater than or equal to 0.8 and less than or equal to 10 d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al.

9. The process according to claim 8, wherein, in step (3), the ratios between the reagents, expressed as molar ratios of the elements, are the following:
X/Y=0.3-2
R.sup.IR.sup.IIR.sup.IIIR.sup.IVNOH/(X+Y)=0.1-0.6 (X+Y)/Z is greater than or equal to 0.8 and less than or equal to 10
H.sub.2O/(X+Y+Z)>10
Alcohol/H.sub.2O=0-1.

10. The process according to claim 9, wherein the following molar ratios between the elements in step (3) are used:
X/Y=0.3-2
R.sup.IR.sup.IIR.sup.IIIR.sup.IVNOH/(X+Y)=0.1-0.4 (X+Y)/Z is greater than or equal to 0.8 and less than or equal to 10
H.sub.2O/(X+Y+Z)>10
Alcohol/H.sub.2O=0.1-0.6.

11. The process according to claim 1, for preparing a compound of formula (A) wherein (Z) is silicon, comprising the following phases: a) a solution (C) is prepared in alcohol, of a hydrolyzable or dispersible compound of silicon, and an amine is also added to this solution, said amine having formula (II)
R.sup.1R.sup.2R.sup.3N(II) wherein R.sup.1 is a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, and R.sup.2 and R.sup.3 are the same or different and are selected from H and a linear, branched or cyclic alkyl containing from 4 to 12 carbon atoms, said alkyl being the same or different from R.sup.I; b) a solution/aqueous suspension (D) is prepared of at least one source of at least one metal X and of at least one source of at least one metal Y; c) the solution (C) and the solution/suspension (D) are stirred until a gel is formed; d) the gel is maintained under stirring, e) the gel is maintained under static conditions, f) the gel resulting from step (e) is dried, obtaining a mixed oxide precursor of formula (A2)
X.sub.aY.sub.bZ.sub.cO.sub.d.pC(A2) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is Si, O is oxygen, C is a nitrogenated compound having formula (II), a, b, c, d are the number of moles of the elements X, Y, Z and O, respectively, p is the weight percentage of C with respect to the total weight of the compound of formula (A2) a, b, c, d are greater than 0 a/b is greater than or equal to 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to 0.8 and less than or equal to 10, d=(2a+6b+Hc)/2 wherein H=4 p is greater than 0 and less than or equal to 40%, g) the product obtained in the previous step is optionally subjected to partial or total calcination, obtaining, respectively, a mixed oxide having the same formula (A2) wherein C is an organic residue deriving from the partial calcination of the nitrogenated compound N, or a mixed oxide of formula (A1):
X.sub.aY.sub.bZ.sub.cO.sub.d(A1) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is Si O is oxygen a, b, c, d are the number of moles of the elements X, Y, Z, O, respectively a, b, c, d are greater than 0 a/b is greater than or equal to 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to 0.8 and less than or equal to 10, d=(2a+6b+Hc)/2 wherein H=4.

12. The process according to claim 11, wherein the following molar ratios between the elements of step (3) are used:
X/Y=0.3-2
R.sup.1R.sup.2R.sup.3N/(X+Y)=0.1-1 (X+Y)/Si is greater than or equal to 0.8 and less than or equal to 10
H.sub.2O/(X+Y+Si)>10
Alcohol/H.sub.2O=0-0.4.

13. The process according to claim 1, for preparing compounds having formula (A) wherein (Z) is aluminum, comprising the following phases: a) a solution (C) is prepared in alcohol, of an amine of formula (II)
R.sup.1R.sup.2R.sup.3N(II) wherein R.sup.1 is a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, and R.sup.2 and R.sup.3 are the same or different and are selected from H and a linear, branched or cyclic alkyl containing from 4 to 12 carbon atoms, said alkyl being the same or different from R.sup.I; b) a solution/aqueous suspension (D) is prepared of soluble or partially soluble sources of at least one metal X, at least one metal Y and a hydrolyzable compound of aluminum; c) the solution (C) and the solution/suspension (D) are mixed until a gel is formed; d) the gel is maintained under stirring, e) the gel is maintained under static conditions, f) the gel resulting from step (e) is dried, obtaining a precursor mixed oxide of formula (A2)
X.sub.aY.sub.bZ.sub.cO.sub.d.pC(A2) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is Al, O is oxygen, C is a nitrogenated compound of formula (II), a, b, c, d are the number of moles of the elements X, Y, Z and O, respectively, p is the weight percentage of C with respect to the total weight of the compound of formula (A2) a, b, c, d are greater than 0 a/b is greater than or equal to 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to 0.3 and less than or equal to 10, d=(2a+6b+Hc)/2 wherein H=3 p is greater than 0 and less than or equal to 40%, g) the product obtained in the previous step is optionally subjected to partial or total calcination, obtaining, respectively, a mixed oxide having the same formula (A2) wherein C is an organic residue deriving from the partial calcination of the nitrogenated compound, or a mixed oxide of formula (A1):
X.sub.aY.sub.bZ.sub.cO.sub.d(A1) wherein X is selected from Ni, Co or a mixture thereof, Y is selected from Mo, W or a mixture thereof, Z is Al O is oxygen a, b, c, d are the number of moles of the elements X, Y, Z, O, respectively a, b, c, d are greater than 0 a/b is greater than or equal to 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to 0.3 and less than or equal to 10, d=(2a+6b+Hc)/2 wherein H=3.

14. The process according to claim 13, wherein, in phase (c), the ratios between the reagents, expressed as molar ratios between the elements, are the following:
X/Y=0.3-2
R.sup.1R.sup.2R.sup.3N/(X+Y)=0.1-1 (X+Y)/Al is higher than or equal to 0.3 and lower than or equal to 10
H.sub.2O/(X+Y+Al)>10
Alcohol/H.sub.2O=0-1.

Description

EXAMPLE 1 (COMPARATIVE)

(1) 6.62 g of octyl amine are dissolved in 40 g of absolute ethanol. A solution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstate hydrate (MTA) in 50 ml of H.sub.2O is then added under stirring to solution A. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.5.

(2) A light green-coloured relatively fluid gel is formed which is left under stirring for 3 hours, gently heating to 70 C. It is left to rest for 72 hours. The gel obtained does not have a supernatant and is left to dry in an oven at 100 C. for 48 hours.

(3) The dried material is calcined in air at 400 C. for 5 hours. The solid obtained has a molar composition Ni.sub.0.05Mo.sub.0.03W.sub.0.03O.sub.0.23 and contains 1.5% by weight of organic residue with respect to the total weight. The specific surface area is 65 m.sup.2/g, the total pore volume 0.228 cm.sup.3/g, the average pore diameter 7.5 nm, calculated from the desorption isotherm.

EXAMPLE 2

(4) 9.04 g of ammonium heptamolybdate (EMA) are dissolved in 100 ml of an aqueous solution of tetrapropyl ammonium hydroxide TPAOH at 5% (solution a). A solution consisting of 14.89 g of nickel nitrate hexhydrate (NiNO) and 4.31 g of tetraethyl orthosilicate TEOS in 80 g of absolute ethanol (solution b) is added under stirring to solution (a). The TPAOH/(Ni+Mo) molar ratio is equal to 0.25. A uniform light green-coloured fluid gel is immediately formed which is left under intensive stirring for 4 hours at 70 C. After resting for 48 hours, the viscous gel is dried at 100 C. for 48 hours and calcined in air at 400 C. for 5 hours. The solid obtained, subjected to chemical analysis, has the following composition (weight percentage): NiO=30.7%, MoO.sub.3=58.8%, SiO.sub.2=10.5%.

(5) The material obtained has a molar composition Ni.sub.0.05Mo.sub.0.05Si.sub.0.02O.sub.0.23 and contains 0.1% by weight of organic residue with respect to the total weight. The specific surface area is 135 m.sup.2/g, the total pore volume 0.32 cm.sup.3/g, the average pore diameter 9.3 nm, calculated from the desorption isotherm.

EXAMPLE 3

(6) 7.96 g of octylamine and 4.33 g of tetraethyl orthosilicate TEOS are dissolved in 40 g of absolute ethanol (solution C). A solution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO) and 9.04 g of ammonium heptamolybdate (EMA) in 50 ml of H.sub.2O (solution D) is then added under stirring to solution C. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6. A light green-coloured relatively fluid gel is formed which is left under stirring for 3 hours, gently heating to 70 C. It is left to rest for 72 hours. The gel obtained does not have a supernatant and is left to dry in an oven at 100 C. for 48 hours. The dried material is calcined in air at 400 C. for 5 hours. The solid obtained, subjected to chemical analysis, has the following composition (weight percentage): NiO=30.7%, MoO3=59.3%, SiO2=10%.

(7) The solid obtained has the following molar composition Ni.sub.0.05Mo.sub.0.05Si.sub.0.02O.sub.0.23 and contains 1.8% by weight of organic residue with respect to the total weight. The specific surface area is 123 m.sup.2/g, the total pore; volume 0.443 cm.sup.3/g, the average pore; diameter 15.9 nm, calculated from the desorption isotherm.

EXAMPLE 4

(8) 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstate hydrate (MTA) are dissolved in 100 ml of an aqueous solution of tetrapropyl ammonium hydroxide TPAOH at 5.2% (solution a). A solution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO) and 5.2 g of TEOS in 80 g of absolute ethanol (solution b) is added under stirring to solution (a). The TPAOH/(Ni+Mo+W) molar ratio is equal to 0.24. A uniform light green-coloured fluid gel is immediately formed which is left under intensive stirring for 4 hours. After resting for 48 hours, the viscous gel is dried at 120 C. for 48 hours.

(9) A quota of material is calcined in air at 400 C. for 5 hours.

(10) The solid obtained, subjected to chemical analysis, has the following composition (weight percentage): NiO=25.2%, MoO.sub.3=23.8%, WO.sub.3=40%, SiO.sub.2=11%.

(11) The solid obtained has the following molar composition Ni.sub.0.05Mo.sub.0.03W.sub.0.03Si.sub.0.02O.sub.0.27 and contains 0.08% by weight of organic residue with respect to the total weight. The specific surface area is 143 m.sup.2/g, the total pore volume 0.404 cm.sup.3/g, the average pore diameter 9.2 nm, calculated from the desorption isotherm,

(12) Another quota of material is calcined in air at 550 C. for 5 hours. The solid obtained has maintained the molar formula Ni.sub.0.05Mo.sub.0.03Si.sub.0.02O.sub.0.27, the specific surface area is 122 m.sup.2/g, the total pore volume 0.339 cm.sup.3/g, the average pore diameter 9.4 nm, calculated from the desorption isotherm.

EXAMPLE 5

(13) 8.22 g of octylamine and 5.2 g of tetraethyl orthosilicate TEOS are dissolved in 40 g of absolute ethanol (solution C). A solution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstate hydrate (MTA) dissolved in 50 ml of H.sub.2O (solution D) is then added under stirring to solution C. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6.

(14) A light green-coloured gel is formed which is left under stirring for 3 hours, gently heating to 70 C. It is left to rest for 48 hours. The gel obtained does not have a supernatant and is left to dry in an oven at 100 C. for 48 hours.

(15) A quota of material is calcined in air at 400 C. for 5 hours. The solid obtained has the following molar composition Ni.sub.0.05Mo.sub.0.03W.sub.0.03Si.sub.0.03O.sub.0.29 and contains 1.9% by weight of organic residue with respect to the total weight. The specific surface area is 142 m.sup.2/g, the total pore volume 0.294 cm.sup.3/g, the average pore diameter 5.5 nm, calculated from the desorption isotherm.

(16) Another quota of solid is calcined in air at 550 C. for 5 hours. The resulting solid has maintained the molar formula Ni.sub.0.05Mo.sub.0.03W.sub.0.03Si.sub.0.02O.sub.0.27, the specific area surface is 86 m.sup.2/g, the total pore volume 0.299 cm.sup.3/g, the average pore diameter 11.7 nm, calculated from the desorption isotherm,

EXAMPLE 6

(17) 7.56 g of octylamine are dissolved in 40 g of absolute ethanol (solution C). A solution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstate hydrate (MTA) dissolved in 50 ml of an aqueous sol containing 14.90 g of an aqueous dispersion of bohemite (Disperal P2 of Sasol) at 10% by weight (solution D) is then added under stirring to solution C. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6. A light green-coloured gel is formed which is left under stirring for 3 hours, heating to 70 C. It is left to rest for 48 hours. The gel obtained does not have a supernatant and is left to dry in an oven at 90 C. for 48 hours. The dried material is subjected to calcination treatments in air at different temperatures: 200, 300 and 400 C. for 5 hours.

(18) The fraction of residual organic component on the sample depends on the thermal treatment to which it is subjected. The table indicates the weight percentage of organic residue, with respect to the total weight of the solid, in relation to the final temperature of the thermal calcination treatment.

(19) TABLE-US-00001 Weight % of organic residue with respect to the total weight of Temperature ( C.) the solid* (% w/w) 200 7.7 300 5.4 400 2.0 *the organic residue was calculated from the weight loss between 200-600 C., measured by TGA analysis, on the materials precalcined at the temperature indicated.

(20) The solid obtained after calcination at 400 C. in air for 5 hours, called sample C, has the following molar composition Ni.sub.0.05Mo.sub.0.03W.sub.0.03Al.sub.0.03O.sub.0.28 and contains 2.0% by weight of organic residue with respect to the total weight of the solid. The specific surface area is 151 m.sup.2/g, the total pore volume 0.381 cm.sup.3/g, the average pore diameter 6.3 nm, calculated from the desorption isotherm.

EXAMPLE 7

(21) 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstate hydrate (MTA) are dissolved in 100 ml of an aqueous solution of tetrapropyl ammonium hydroxide TPAOH at 5.2% (solution a). A solution consisting of 14.9 g of cobalt nitrate hexhydrate (CoNO) and 5.2 g of TEOS in 80 g of absolute ethanol (solution b) is added under stirring to solution (a). The TPAOH/(Ni+Mo+W) molar ratio is equal to 0.24.

(22) A uniform purple-coloured fluid gel is immediately formed which is left under intensive stirring for 4 hours, heating to 70 C. It is left to rest for 3 days and is finally dried at 100 C. for 72 hours and calcined in air at 400 C. for 5 hours.

(23) The solid obtained, subjected to chemical analysis, has the following composition (weight percentage): CoO=24.8%, MoO.sub.3=23.8%, Wo.sub.3=41.4%, SiO.sub.2=10%.

(24) The solid obtained has the following molar composition Co.sub.0.05Mo.sub.0.03W.sub.0.03Si.sub.0.03O.sub.0.29 and contains 0.1% by weight of organic residue with respect to the total weight.

(25) The specific surface area is 115 m.sup.2/g, the total pore volume 0.255 cm.sup.3/g, the average pore diameter 9.1 nm, calculated from the desorption isotherm.

EXAMPLE 8

(26) 8.22 g of octylamine and 5.2 g of tetraethyl orthosilicate TEOS are dissolved in 40 g of absolute ethanol (solution C). A solution consisting of 14.9 g of cobalt nitrate hexahydrate (CoNO), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstate hydrate (MTA) dissolved in 50 ml of H.sub.2O (solution D) is then added under stirring to solution C. The octylamine/(Co+Mo+W) molar ratio is equal to 0.6.

(27) A purple gel is formed which is left under stirring for 3 hours at 70 C. It is left to rest for 48 hours. The gel obtained is dried in an oven at 90-100 C. for 48 hours. The dried material is calcined in air at 400 C. for 5 hours.

(28) The solid obtained, subjected to chemical analysis, has the following composition (weight percentage): CoO=24.7%, MoO.sub.3=24.2%, WO.sub.3=41.1%, SiO.sub.2=10%.

(29) The solid obtained has the following molar composition Co.sub.0.05Mo.sub.0.03W.sub.0.03Si.sub.0.03O.sub.0.29 and contains 2.1% by weight of organic residue with respect to the total weight.

(30) The specific surface area is 90 m.sup.2/g, the total pore volume 0.182 cm.sup.3/g, the average pore diameter 4.8 5 nm, calculated from the desorption isotherm.

EXAMPLE 9

(31) 7.56 g of octylamine are dissolved in 80 g of absolute ethanol (solution C). A solution consisting of 12.74 g of nickel acetate tetrahydrate (NiAc), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium, metatungstate hydrate (MTA) dissolved in 200 ml of an aqueous sol containing 14.9 g of an aqueous dispersion at 0.6% in acetic acid of bohemite (Disperal P3 of Sasol) at 10% by weight (solution D) is then added under stirring to solution C. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6.

(32) A light green-coloured gel is formed which is left under stirring for 8 hours, heating to 70 C. It is left to rest for 48 hours. The gel is dried in an oven at 80 C. for 48 hours.

(33) The dried material is subjected to calcination treatment in air at 400 C. for 5 hours.

(34) The solid obtained has the following molar composition Ni.sub.0.05MO.sub.0.03W.sub.0.03Al.sub.0.03O.sub.0.28 and contains 2.2% by weight of organic residue with respect to the total weight. The specific surface area is 111 m.sup.2/g, the total pore volume 0.19 cm.sup.3/g, the average pore diameter 3.7 nm, calculated from, the desorption isotherm.

EXAMPLE 10

(35) 8.98 g of Bohemite SASOL DISPERSAL P2 (73% w/w Al.sub.2O.sub.3) are dispersed in 100 g of demineralized H.sub.2O. 89.34 g of nickel nitrate hexahydrate (NiNO), 27.12 g of ammonium heptamolybdate (EMA) and 41.88 g of ammonium metatungstate hydrate (MTA) are added to the dispersion in order and the mixture is brought to a volume of about 300 ml with demineralized H.sub.2O.

(36) 45.30 g of octylamine (99% w/w) are diluted in 240 g of absolute ethanol and subsequently added to the dispersion. The gel formed is heated, under stirring to 70 C. in an open beaker for 14 hours and is concentrated until a homogeneous gel is obtained, which is left to age for 40 hours. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6.

(37) Half of the gel is dried and calcined at 400 C. The solid obtained has the following molar composition Ni.sub.0.15Mo.sub.0.08W.sub.0.09Al.sub.0.06O.sub.0.75 and contains 2.1% by weight of organic residue with respect to the total weight. The remaining gel is introduced into a Brabender mixer.

(38) 60 g of Bohemite SASOL DISPERSAL P2 and 30 ml of H.sub.2O are added, under mixing, at 50 rpm. The mixture is heated to 80 C. for about 3 hours until a homogeneous paste with a suitable consistency for being extruded, is obtained. The mixture is cooled and the compound is discharged and extruded with a Hosokawa extruder of the Hutt type having a diameter of the holes of 1.5 mm. The extruded product is left to age at room temperature for a night, then dried in a static oven at 90 C. for 5 hours and calcined in a flow of air according to the following program:

(39) from room temperature to 100 C. with a rise of 2 C./min, at 100 C. for 5 hours then at 120 C., 2 C./min, for 5 hours, at 130 C., 2 C./min, for 5 hours, at 160 C., 2 C./min, for 5 hours, at 200 C., 2 C./min, for 5 hours and at 400 C., 2 C./min, for 10 hours.

(40) The final extruded product consists of 50% by weight of mixed oxide and 50% by weight of alumina binder.

(41) The extruded product has a good mechanical resistance.

EXAMPLE 11 (COMPARATIVE)

(42) An extruded product is prepared using a reaction mixture in which the octylamine/(Ni+Mo+W) molar ratio is equal to 1.5.

(43) 69.1 g of Bohemite SASOL DISPERSAL P2 (73% w/w Al.sub.2O.sub.3) are dispersed in 300 g of demineralized H.sub.2O.

(44) 53.5 g of nickel nitrate hexahydrate (NiNO), 16.2 g of ammonium heptamolybdate (EMA) and 25.1 g of ammonium metatungstate hydrate (MTA) are added to the dispersion in order and the mixture is brought to a volume of about 500 ml with demineralized H.sub.2O.

(45) 75.60 g of octylamine (99% w/w) are diluted in 400 g of absolute ethanol and subsequently added to the dispersion. The octylamine/(Ni+Mo+W) molar ratio is equal to 1.6.

(46) The gel formed is heated, under stirring to about 70 C. in an open beaker for 16 hours. It is left under static conditions for a night. The gel is introduced into a Brabender mixer and mixed at 50 rpm at 50 C. for 0.5 hours and at 80 C. for 3 hours until a paste is obtained, suitable for being extruded with a Hosokawa extruder of the Hutt type having a diameter of the holes of 1.5 mm. The extruded product is left to age at room temperature for a night, then dried in a static oven at 90 C. for 5 hours and calcined in a flow of air according to the following program:

(47) from room temperature to 100 C. with a rise of 2 C./min, at 100 C. for 5 hours then at 120 C., 2 C./min, for 5 hours, at 130 C., 2 C./min, for 5 hours, at 160 C., 2 C./min, for 5 hours, at 200 C., 2 C./min, for 5 hours and at 400 C., 2 C./min, for 10 hours.

EXAMPLE 12

(48) 76.1 g of octylamine and 48.1 g of tetraethyl orthosilicate TEOS are dissolved in 370 g of absolute ethanol (solution C). A solution consisting of 137.9 g of nickel nitrate hexahydrate (NiNO), 41.9 g of ammonium heptamolybdate (EMA) and 64.6 g of ammonium metatungstate hydrate (MTA) dissolved in 460 ml of H.sub.2O (solution D) is then added under stirring to solution C. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6.

(49) A light green-coloured gel is formed which is concentrated to 600 g by evaporation at 80 C. After 48 hours of resting, 80 g of the gel obtained are collected. A solid is obtained from the remaining quantity which can be easily pulverized, after drying at 100 C. for 48 hours and calcination in air at 400 C. for 5 hours.

(50) The solid obtained has the following molar composition Ni.sub.0.41Mo.sub.0.21W.sub.0.23Si.sub.0.20O.sub.2.13 and contains 2.2% by weight of organic residue with respect to the total weight.

(51) 120 g of this calcined powder are amalgamated with the 80 g of gel previously collected and the homogeneous paste thus obtained is drawn directly at room temperature in a Brabender extruder. Rigid formulates are obtained with a specifically regulated sizing of 5 mm in length and 1.5 mm in diameter. After calcination at 400 C. for 5 hours, a material with a good mechanical resistance is obtained.

(52) The extruded product obtained has a surface area equal to 136 m.sup.2/g, a total pore volume of 0.26 cm.sup.3/g and an average pore diameter of 7.4 nm, calculated from the desorption isotherm.

EXAMPLE 13

(53) 54 g of Bohemite SASOL DISPERSAL P2 (73% w/w Al.sub.2O.sub.3) are dispersed in 600 g of demineralized H.sub.2O.

(54) 554 g of nickel nitrate hexahydrate (NiNO), 162 g of ammonium heptamolybdate (EMA) and 251 g of ammonium metatungstate hydrate (MTA) are added to the dispersion in order and the mixture is brought to a volume of about 1,800 ml with demineralized H.sub.2O.

(55) 271 g of octylamine are diluted in 1,440 g of absolute ethanol and subsequently added to the dispersion.

(56) The gel formed is heated, under stirring to 60 C. for 15 hours and aged at room temperature for 20 hours. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.5.

(57) 630 g of gel are obtained. 50 g of gel are dried and calcined at 400 C. The solid obtained has the following molar composition Ni.sub.0.15Mo.sub.0.08W.sub.0.08Al.sub.0.06O.sub.0.72 and contains 2.2% by weight of organic residue with respect to the total weight.

(58) 140 g of Bohemite SASOL DISPERSAL P2 and 30 ml of H.sub.2O are added, under stirring at 50 rpm.

(59) The mixture is heated to 80 C. for about 3 hours until a homogeneous paste having a consistency suitable for extrusion, is obtained. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.5.

(60) The mixture is cooled and the compound is discharged and extruded with a Hosokawa extruder of the Hutt type having a hole diameter of 1.5 mm.

(61) The extruded product is left to age at room temperature for a night, then dried in a static oven at 90 C. for 5 hours and calcined in a flow of air with a temperature rise of 2 C./min and the following steps:

(62) 110 C. for 16 hours, 120 C. for 1 hour, 140 C. for 1 hour, 160 C. for 10 hours, 400 C. for 10 hours, in air.

(63) The final extruded product consists of 80% by weight of mixed oxide and 20% by weight of alumina binder.

(64) The organic residue, calculated from the weight loss between 200-600 C., measured by means of TGA analysis, is equal to 2.4% by weight with respect to the total weight of the extruded product.

(65) The extruded product has a good mechanical resistance.

EXAMPLES 14-15

(66) The material obtained in Example 1 and the material obtained in Example 6 by calcination at 400 C. (sample C), were used as catalysts in the following hydrotreatment catalytic test.

(67) The fixed bed reactor is charged with 5 grams of catalyst previously pressed and granulated (20-40 mesh).

(68) The process takes place in 2 phases: sulfidation of the catalyst and hydrotreatment step.

(69) a) Sulfidation

(70) The catalyst is treated with a sulfiding mixture consisting of Straight Run Gasoil, with the addition of Dimethyl disulfide, so as to have a concentration of S equal to 2.5 by weight with respect to the total weight of the sulfiding mixture. The sulfidation conditions used are:

(71) LHSV=3 hours.sup.1

(72) P=30 bar

(73) T=340 C.

(74) H.sub.2/sulfiding mixture=200 Nl/l.

(75) b) Hydrotreatment

(76) The reaction is carried out under the following conditions:

(77) T=320 C.

(78) P=60 bar

(79) Liquid feedstock flow-rate: 8 ml/hour

(80) H.sub.2 flow-rate: 5 Nl/hour

(81) WHSV=1.35 hour.sup.1

(82) The feedstock stream consists of gasoil coming from thermal cracking and contains 23,900 ppm of sulfur and 468 ppm of nitrogen. The activity of the catalysts is expressed as hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) conversion.

(83) After 120 hours, the conversion, data indicated in the following table were measured:

(84) TABLE-US-00002 Example Catalyst HDN HDS 14 Ex. 1 (comparative) 71.5 90.6 15 Ex. 6 81.0 92.5

(85) As is evident from comparing the results, the material of the present invention is much more active.

EXAMPLES 16-17

(86) The sulfidation and hydrotreatment test are carried out as described for Examples 14-15.

(87) A comparison is made of the catalysts obtained in Examples 10 and 11; the following table indicates the data measured at 320 C., after 120 hours. The activity of the catalysts is expressed as hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) conversion.

(88) TABLE-US-00003 Example Catalyst HDN HDS 16 Ex. 10 66.7 92.5 17 Ex. 11 (comparative) 63.3 86.2

(89) It is evident that upon increasing the content of nitrogenated compound in the synthesis, less active materials are obtained in the hydrotreatment.

EXAMPLES 18-19

(90) The sulfidation was carried out as described for Examples 14-15. The hydrotreatment reaction is carried out under the following conditions:

(91) T=340 C.

(92) P=60 bar

(93) Liquid feedstock flow-rate: 8 ml/hour

(94) H.sub.2 flow-rate: 5 Nl/hour

(95) WHSV=1.35 hour.sup.1

(96) The hydrocarbon feedstock used is gasoil coming from thermal cracking and contains 23,900 ppm of sulfur and 468 ppm of nitrogen.

(97) A comparison is made of the catalysts obtained in Examples 12 and 13. The following table indicates the conversion data measured at the reaction temperature of 340 C., after 180 hours. The activity of the catalysts is expressed as hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) conversion.

(98) TABLE-US-00004 Example Catalyst HDN HDS 18 Ex. 12 99.5 99.5 19 Ex. 13 90.6 98.0

(99) The optimum performances of the materials of the present invention are evident.

EXAMPLE 20

(100) The catalyst of Example 6 is sulfided as described in Examples 14-15 and used for the hydrotreatment of gasoil coming from thermal cracking which contains 23,900 ppm of sulfur and 468 ppm of nitrogen.

(101) The hydrotreatment conditions are the following:

(102) T=340 C.

(103) P=60 bar

(104) Liquid feedstock flow-rate: 8 ml/hour

(105) H.sub.2 flow-rate: 5 Nl/hour

(106) WHSV=1.35 hour.sup.1

(107) The activity of the catalyst is expressed as hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) conversion.

(108) After 180 hours at the reaction temperature of 340 C., the following conversion data are obtained:

(109) HDS=99.5

(110) HDN=99.4

EXAMPLE 21

(111) 5.92 g of hexylamine are dissolved in 40 g of absolute ethanol (solution C). A solution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstate hydrate (MTA) dissolved in 50 ml of an aqueous sol containing 14.9 g of an aqueous dispersion of bohemite (Disperal P2 of Sasol) at 10% by weight (solution D) is then added under stirring to solution C. The hexylamine/(Ni+Mo+W) molar ratio is equal to 0.6.

(112) A light green-coloured gel is formed, which is left under stirring for 3 hours, heating to 70 C. It is left to rest for 48 hours. The gel obtained does not have a supernatant, and is dried in an oven at 90 C. for 48 hours.

(113) The solid obtained after calcination in air at 400 C. for 5 hours has a specific surface area of 140 m.sup.2/g, a total pore volume of 0.400 cm.sup.3/g, am average pore diameter of 7.5 nm, calculated from the desorption isotherm.

(114) The solid obtained after calcination in air at 550 C. for 5 hours has a molar composition Ni.sub.0.05Mo.sub.0.03W.sub.0.03Si.sub.0.02O.sub.0.27, a specific surface area of 86 m.sup.2/g, a total pore volume of 0.346 cm.sup.3/g, an average pore diameter 11.0 nm, calculated from the desorption isotherm.