Nanostructured titania catalyst with stabilized acidity and process thereof

• US 10,456,773 B2
• Filed: 09/25/2014
• Issued: 10/29/2019
• Est. Priority Date: 09/25/2013
• Status: Active Grant

• Current Assignee: Instituto Mexicano Del Petrã³Leo (Gobierno Federal De Los Estados Unidos Mexicanos)
• Original Assignee: Instituto Mexicano Del Petrã³Leo (Gobierno Federal De Los Estados Unidos Mexicanos)
• Inventors: Castillo Cervantes, Salvador, Mejia Centeno, Isidro, Marin Cruz, Jesus, Galicia Gomez, Policarpo, Camposeco Solis, Roberto
• Primary Examiner(s): Mayes, Melvin C.
• Assistant Examiner(s): Patel, Smita S
• Application Number:
  US14/496,424
• Publication Number:
  US 20150087506A1
• Time in Patent Office: 1,860 Days
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 23/30 Tungsten
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/647 2-50 nm
• CPC Class Codes: B01J 37/036 to form a gel or a cogel
• CPC Class Codes: B01J 37/06 Washing B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/08 Heat treatment B01J37/0009, B01J37/0018 take precedence

Abstract

The present invention is directed to a process for obtaining a nanostructured titania catalyst with stabilized acidity through the sol-gel method and hydrotreatment and thermal activation; constituted basically by titanium oxide, specially characterized of being as nanostructures in its evolution nanocrystals-nanotubes-nanocrystals, that gives special physicochemical properties such as high specific area, purity and phases stability, acidity stability and different types of active acid sites, such as a capacity to disperse and stabilize metallic particles with high activity mainly in catalytic processes.

Claims

1. A nanostructured titania catalyst with stabilized acidity comprising titanium dioxide nanocrystals having crystalline/amorphous phase containing hydrogen titanate and a hydrogen titanate/anatase combination,

wherein said catalyst is obtained by a process including a sol-gel method step to obtain hydrogen titanate nanocrystals, a hydrotreatment step of the hydrogen titanate nanocrystals to obtain titanium dioxide nanotubes, and thermal activation step to convert at least a portion of the resulting titanium dioxide nanotubes to titanium dioxide nanocrystals,

wherein said thermal activation step is at a temperature of 100-350°

C. and said catalyst comprises titanium dioxide nanocrystals having crystalline/amorphous phase containing 95-100 wt % of hydrogen titanate and further containing combination of 96 wt % of hydrogen titanate and 4 wt % of anatase;

or

wherein said thermal activation step is at a temperature of 350-600°

C. and said catalyst comprises titanium dioxide nanocrystals having crystalline/amorphous phase containing 20-33 wt % of hydrogen titanate and further containing combination of 22 wt % of hydrogen titanate and 78 wt % of anatase.

2. A nanostructured titania catalyst with stabilized acidity according to claim 1, wherein said catalyst has internal, external and interlaminar diameter ranges as follows:

3. A nanostructured titania catalyst with stabilized acidity according to claim 2, wherein said catalyst has the following texture properties:

4. A nanostructured titania catalyst with stabilized acidity according to claim 3 wherein said catalyst has the following properties of the bandgap energy (Eg):

5. A nanostructured titania catalyst with stabilized acidity according to claim 4, wherein said catalyst has the following hydroxylation grades:

6. A nanostructured titania catalyst with stabilized acidity according to claim 1, wherein said catalyst is obtained by the process comprising the steps of:

a sol-gel method step

I) preparation of an alcohol solution as a preparation of a feeding charge and consists of an addition of a reflux system with stirring consisting of a titanium alkoxide having three or four branched or lineal carbons in an alcohol solution, with three or four lineal or branched carbon alcohols;

II) forming a solution in acid media by adding an acid to the alcohol solution obtained in step I) controlling pH from 1 to 5, where the acid used is selected from the group consisting of hydrochloric, nitric, and acetic acid;

III) hydrolysis by mixing the solution of step II in an acid media obtained in step II) under stirring and reflux conditions at a temperature of 70 to 80°

C., stabilize the resulting mixture and adding dropwise bidistilled water in a molar ratio of 1-2/0.100-0.150, continuing with the reflux until gel formation;

IV) aging by submitting the gel obtained in step III) to an aging treatment under the same stirring and reflux conditions of step III) for 1 to 24 hours for formation of a nanostructured titania;

V) drying the nanostructured titania obtained in step IV) at a temperature of 50 to 80°

C. for 1 to 24 hours;

VI) activation or calcination by submitting the dry nanostructured titania obtained in step V) to a calcination step, optionally with an oxidizing or reducing atmosphere at a temperature of 200 to 600°

C., for 1 to 12 hours to obtain titanium dioxide nanocrystals; and

a hydrothermal process step

I) normality of an alkaline solution (NaOH) by mixing the titanium dioxide nanocrystals with a solution of sodium hydroxide 5 to 10N (NaOH) with stirring at 100 to 200 rpm, at a temperature of 130 to 180°

C. during the drying obtained in step V) to a calcination step, optionally with an oxidizing and reducing atmosphere, at a temperature of 200 to 600°

C. for 1 to 12 hours;

II) reaction temperature by subjecting the titanium dioxide nanocrystals mixed with a solution of sodium hydroxide 5 to 10 N at a temperature range of 130 to 180°

C.;

III) reaction time and stirring by submitting the titanium dioxide nanocrystals mixed with a sodium hydroxide 5 to 10N solution in a temperature range of 130 to 180°

C. for 12 to 24 hours with stirring at 100 to 200 rpm to obtain titanium dioxide nanotubes;

IV) washing by submitting the titanium dioxide nanotubes obtained by the steps I, II and III, to a washing process with hydrochloric acid (HCl), up to obtain an acid pH of 1 to 3, afterwards a second washing with water is carried out up to obtain a pH from 6 to 7; and

V) activation or calcination by submitting the titanium dioxide nanotubes of step IV, to a thermal drying treatment at 70 to 80°

C., once dried, submitting to thermal calcination treatment at 100 to 600°

C., at a heating profile of 5°

C. per minute, to obtain nanostructured titanium dioxide nanocrystals with two calcination profiles at 350°

C. and 600°

C., when these temperatures are obtained, are maintained for 1 to 4 hours to obtain said titanium dioxide nanocrystals.

7. The nanostructured titania catalyst according to claim 6, wherein the titanium alkoxide used in step I) has three or four branched or linear carbons.

8. The nanostructured titania catalyst according to claim 7, wherein the preparation of the solution in the acid media from the step II) is carried out with a pH from 2 to 3.

9. The nanostructured titania catalyst according to claim 8, wherein the preparation of the acid media solution of step II) is carried out with nitric acid.

10. The nanostructured titania catalyst according to claim 6, wherein the water/alkoxide molar ratio used in the step III) is 1-2/0.120-0.130.

11. The nanostructured titania catalyst according to claim 6, wherein the drying of the step V) is carried out at 60-70°

C. for 4 to 12 hours.

12. The nanostructured titania catalyst according to claim 6, wherein the activation or calcination of the step VI) is carried out at 300-500°

C. for 3 to 9 hours.

13. The nanostructured titania catalyst according to claim 6, wherein the NaOH solution of the step I) is 5 to 10 N.

14. The nanostructured titania catalyst according to claim 6, wherein the reaction temperature of the step II), is carried out at 130 to 180°

C.

15. The nanostructured titania catalyst according to claim 6, wherein the stirring time of the step III), is 12 to 24 hours with a stirring at 100 to 200 rpm.

16. The nanostructured titania catalyst according to claim 6, wherein the washing of the step IV) is carried out with HCl to obtain a pH of 1 to 3.

17. The nanostructured titania catalyst according to claim 6, wherein the washing of the step IV) is carried out with deionized water with a pH of 6 to 7.

18. The nanostructured titania catalyst according to claim 6, wherein the activation or calcination of the step VI) is carried out at 350-600°

C. for 1 to 4 hours.

19. A nanostructure titania catalyst support with stabilized acidity according to claim 1, as a support of active metals in heterogeneous or homogeneous catalytic processes;

as a covering of catalytic matrixes;

as a film over different types of substrates and optionally with active metals.

20. The nanostructured titania catalyst of claim 1, wherein said catalyst is obtained by thermal activation at a temperature of 350-600°

C. and where said catalyst comprises 20-33 wt % of hydrogen titanate.

21. The nanostructure titania catalyst of claim 1, wherein said catalyst is obtained by an activation temperature of 100-350°

C. and said catalyst comprises 95-100 wt % of hydrogen titanate.

22. The nanostructure titania catalyst of claim 21, wherein said catalyst further comprising combination of titanate/anatase including 96 wt % of hydrogen titanate and 4 wt % of anatase, and has a surface area of 320-350 m2/g and an average pore diameter of 20-40 angstroms.

23. The nanostructure titania catalyst of claim 20, wherein said catalyst further comprising combination of hydrogen titanate/anatase including 22 wt % hydrogen titanate and 78 wt % anatase, and has a surface area of 200-280 m2/g and an average pore diameter of 20-30 angstroms.