Claims:1. A catalyst composition for single step depolymerization of lignin, said composition comprising:
a. 1 to 10 %of mesoporous Y Zeolite;
b. 20 to 40% of SiO2-Al2O3;
c. 40 to 60 % of pseudoboehmite alumina;
d. 10 to 25% WO3;
e. 1to 5% NiO; and
f. at least one chelating agent.

2. A process for preparing a catalyst composition for depolymerization of lignin, said process comprising:
a. preparation of MesoY/SiO2-Al2O3/Al2O3 extrudates; and
b. sequential loading of active metals on MesoY/SiO2-Al2O3/Al2O3 extrudates.

3. A process for preparing a catalyst composition for depolymerization of lignin as claimed in claim 2, said process comprising:
ii. preparing MesoY/SiO2-Al2O3/Al2O3 extrudates
a. mixing mesoporous Y Zeolite, SiO2-Al2O3 and pseudoboehmite alumina in Kneader;
b. preparing extrudates with 1M acetic acid solution; and
c. drying and calcining to obtain a extrudates;
ii active metal loading on extrudates
a. spray impregnation of tungsten source and chelating agent on to extrudate obtained in step (i), at a pH of 5-5.2;
b. aging at room temperature and drying at 90 °C tungsten loaded extrudate, followed by calcination at 500 °C; and
c. calcinated extrudate of pervious step is spray impregnated with nickel source and chelating agent at a pH of 5, followed by drying at 100 °C.

4. The process as claimed in claim 3 wherein the tungsten sources is selected from ammonium metatungstate or phoshphotungstic acid, and nickel source is nickel acetate.

5. The process as claimed in claim 3, wherein the chelating agent is citric acid (CA), amino acid, glutamic acid, nitriloacetic acid, glutaric acid, succinic acid, or combination thereof.

6. The process as claimed in claim 3, wherein the chelating agent is a combination of citric acid and glutamic acid.

7. The process as claimed in claimed in claim 3, wherein the process comprising mixing of mesoporous Y Zeolite in the range of 5-20%, SiO2-Al2O3 in the range of 50-80% and pseudoboehmite alumina in the range of 10-20%.

8. The process as claimed in claim 3, wherein drying and calcination of step i (c) at 100°C, and 500°C, respectively.

9. A process for depolymerization of lignin, said process comprising:
a. sulfidation of catalyst at 350 °C for 20 hours;
b. dissolving kraft lignin in solvent; and
c. depolymerizing the lignin solution of step b) at 300-400 °C, 30-80 bar pressure, 0.1-1.0 WHSV, H2/feed ratio 50-1000 Nm3/m3.

10. The process as claimed in 10, wherein the lignin conversion ≤ 90% and yield of monomers is ≤ 60%; wherein the solvent is selected from methanol, ethanol, acetone, and ethylene glycol; and wherein the lignin content of lignin solution is 0.5-2%.
, Description:FIELD OF THE INVENTION
The present invention relates to a catalyst composition for single step depolymerization of lignin to fuels/chemicals and process for making the same, which involves selective depolymerization of lignin to aromatics and phenols with a higher yield employing a multifunctional catalyst.

BACKGROUND OF THE INVENTION
The development of renewable fuels and chemicals from biomass-based resources is critical to accelerating the transition to a more environmentally friendly chemical manufacturing industry. Among the several pathways provided by nature to accelerate the transition, lignin, as the most abundantly available biopolymer, provides a plethora of chances to produce aromatic building blocks that are valuable in the pharmaceutical industry. Lignin is also a significant industrial by-product produced by pulp and paper mills and cellulosic ethanol production, resulting in a bulk feedstock known as technical lignin that is used in a variety of applications. Developing economically viable methods for the conversion of lignin into high-value chemicals and fuels is one of the most difficult obstacles to overcome in the process of lignin valorization. Lignin depolymerization techniques are evolving, and they are giving exciting potential for the effective conversion of this renewable raw material into valuable chemicals soon. The transition from fundamental research to practical applications in the core of the biorefineries, on the other hand, constitutes a significant obstacle to overcome.

WO2017124304A1 describes an amino acid-zeolite composite material, as well as a microporous-mesoporous level zeolite material derived from it, as well as a method of preparation and use. The amino acid-zeolite composite material includes a zeolite structure and dispersed amino acid molecules deposited in the zeolite structure's pore structure, where the zeolite structure includes a microporous structure and a mesoporous structure, with at least part of the mesoporous structure inside a crystal.

WO2002099014A2 describes process to prepare a base oil starting from a slack wax containing feedstock by (a) contacting the feedstock in the presence of hydrogen with a sulphided hydride sulphurisation catalyst comprising nickel and tungsten on an acid amorphous silica-alumina carrier and (b) performing a pour point reducing step on the effluent of step (a) to obtain the base oil.

CN107344111A relates to processes for conversion of a feedstock comprising Cs+ aromatic hydrocarbons to lighter aromatic products in which the feedstock and optionally hydrogen are contacted in the presence of the catalyst composition under conversion conditions effective to dealkylate and transalkylate said C8+ aromatic hydrocarbons to produce said lighter aromatic products comprising benzene, toluene, and xylene. The catalyst composition comprises a zeolite selected from zeolite beta, ZSM-4, ZSM-5, ZSM-11, ZSM-12, ZSM-20, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-50, ZSM-57, ZSM-58, MCM-68, faujasite zeolite, mordenite zeolite or a MCM-22 family material, a first metal of group 6 in an amount of 0.001 wt% to 20.0 wt%, and a second metal of group 9 or 10 in an amount of 0.001 wt% to 20.0 wt %, and is treated with a source of sulfur and/or a source of steam.

WO2013060666A1 relates to the invention relates to a process for preparing a hydro conversion catalyst based on a modified zeolite of the FAU framework type with preserved crystallinity and microporosity, comprising the steps of: A- preparation of a modified zeolite of the FAU framework type, whose intracrystalline structure presents at least one network of micropores, at least one network of small mesopores with a mean diameter of 2 to 5 nm and at least one network of large mesopores with a mean diameter of 10 to 50 nm; these various networks being interconnected; B- mixing the zeolite with a binder, shaping the mixture, and then calcining; C- impregnation of the shaped zeolite with at least one compound of a catalytic metal chosen from compounds of a metal from group VIII and/or from group VIB, in acidic medium, provided that at least one compound of a catalytic metal is soluble within said acidic medium and that the acid acts as a complexing or chelating agent for at least one compound of a catalytic metal. The invention also relates to a catalyst obtained via this process and to the use thereof.

WO2015033350A1 relates to disclosure provides a catalyst composition for conversion of biomass to crude bio-oil. The composition comprises at least one metal compound, at least one support and at least one stabilizing/solubilizing agent. Also disclosed are processes for the preparation of catalyst composition, and hydrothermal conversion of biomass to crude bio-oil.

US20180258251A1 The present invention is related to a catalytic process, which includes catalytic compositions for depolymerisation and deoxygenation of lignin contained in the biomass for obtaining aromatic hydrocarbons. The catalytic composition consists of at least one non-noble element from group VIIIB of the periodic table supported on a mesoporous matrix composed of an inorganic oxide, which can be alumina surface-modified with a second inorganic oxide with the object of inhibiting the interaction between the active component and the support. The process of lignin depolymerisation consists of dissolving lignin in a mixture of protic liquids, reacting it a reaction system by batch or in continuous flow at inert and/or reducing atmosphere, at a temperature of between 60 to 320° C. and a pressure of from 5 to 90 kg/cm2. When the reaction is developed into a batch system, oxygenated aromatic hydrocarbons are mainly produced, both by thermal as well as catalytic depolymerisation, whereas in a continuous flow reaction system, deoxygenated aromatic hydrocarbons are produced.

The suggested processes and knowledge in identified prior arts are associated with certain drawbacks such as low yielding and are non-energy efficient because they require multiple heating of the biomass. Accordingly, there is a need for an energy efficient, time saving and high yielding process for depolymerization of lignin to aromatics and phenols with higher yield using multifunctional catalyst.

SUMMARY OF THE INVENTION
The present invention discloses a catalyst composition for single step depolymerization of lignin, process for preparing the same. In one aspect of present invention provides catalyst composition for single step depolymerization of lignin, said composition comprising:
a) 1 to 10% of mesoporous Y Zeolite;
b) 20 to 40% of SiO2-Al2O3;
c) 40 to 60 % of pseudoboehmite alumina;
d) 10 to 25% WO3;
e) 1to 5% NiO; and
f) at least one chelating agent.

In another aspects the present invention provides a two-step process for preparation of a catalyst composition for depolymerization of lignin, said process comprising:
i. preparing MesoY/SiO2-Al2O3/Al2O3 extrudates
a) mixing mesoporous Y Zeolite, SiO2-Al2O3 and pseudoboehmite alumina in Kneader;
b) preparing extrudates with 1M acetic acid solution; and
c) drying at 100°C and calcining at 500°C to obtain a extrudates;
ii active metal loading on extrudates
a) spray impregnation of tungsten source and chelating agent on to extrudate obtained in step (i), at a pH of 5-5.2;
b) aging at room temperature and drying at 90 °C tungsten loaded extrudate, followed by calcination at 500 °C; and
c) calcinated extrudate of pervious step is spray impregnated with nickel source and chelating agent at a pH of 5, followed by drying at 100 °C.

In yet another aspects the present invention, the tungsten sources is selected from ammonium metatungstate or phoshphotungstic acid, and nickel source is nickel acetate.

In yet another aspects the present invention, the chelating agent is citric acid (CA), amino acid, glutamic acid, nitriloacetic acid, glutaric acid, succinic acid, or combination thereof.

In another aspects the present invention the process comprising mixing of mesoporous Y Zeolite in the range of 5-20%, SiO2-Al2O3 in the range of 50-80% and pseudoboehmite alumina in the range of 10-20%.

In one of the aspects the present invention provides a process for depolymerization of lignin, said process comprising:
a) sulfidation of catalyst at 350 °C for 20 hours;
b) dissolving kraft lignin in solvent; and
c) depolymerizing the lignin solution of step b) at 300-400 °C, 30-80 bar pressure, 0.1-1.0 WHSV, H2/feed ratio 50-1000 Nm3/m3.
In yet another aspect of the present invention the solvent is selected from methanol, ethanol, acetone, and ethylene glycol; and wherein the lignin content of lignin solution is 0.5-2%.

In another aspect of the present invention lignin conversion ≤ 90% and yield of monomers is ≤ 60% .

OBJECTIVES OF THE INVENTION:

It is the primary objective of the present disclosure to provide a catalyst composition for depolymerization of lignin.

It is the primary objective of the present disclosure to provide a catalyst composition for depolymerization of lignin to fuels/chemicals.

It is further objective of the present invention to provide a catalyst composition for single step depolymerization of lignin to fuels/chemicals.

It is further objective of the present invention to provide a process for preparation of the catalyst for depolymerization of lignin.

It is further objective of the present invention to provide a multi-functional catalyst with active metals loaded on MesoY/SiO2-Al2O3/Al2O3 extrudate.

DETAILED DESCRIPTION OF THE INVENTION
While the invention has been described and illustrated with reference to certain embodiments thereof, those skilled in the art will appreciate that various adaptations, changes, modifications, substitutions, deletions, or additions of procedures and protocols may be made without departing from the spirit and scope of the invention. It is intended, therefore, that the invention be defined by the scope of the claims which follow and that such claims be interpreted as broadly as is reasonable.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.

The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products and processes are clearly within the scope of the disclosure, as described herein.

According to the main embodiment, the present invention provides a catalyst composition for single step depolymerization of lignin to fuels/chemicals and a process for preparing the catalyst composition.

Preparation of MesoY/SiO2-Al2O3/Al2O3 extrudates
In one of the embodiment, Mesoporous Y Zeolite, SiO2-Al2O3, and Pseudoboehmite alumina are mixed in a kneader and extrudates prepared with 1M Acetic acid solution The obtained extrudates were dried at 100 °C and calcined at 500 °C.

In another embodiment of the present invention, amount of Mesoporous Y Zeolite is 5-20%, SiO2-Al2O3 is 50-80% and Pseudoboehmite alumina is 10-20%, in the extrudates.

Preparation of NiW loaded MesoY/SiO2-Al2O3/Al2O3
In one of the embodiment, active metal including Nickel (Ni) and Tungsten (W) loaded on the MesoY/SiO2-Al2O3/Al2O3 extrudates, in the following order:

 W loading: Using spray impregnation, tungsten and chelating additive components are deposited onto support extrudates. While loading W along with the chelating agents, pH of impregnating solution is between 5-5.2. The obtained material is aged at room temperature and dried at 90 °C, followed by calcination at 500 °C.

 Ni loading: Spray impregnation of Nickel source and chelating agent onto the above obtained material, at a pH of 5. Ni loading is done in single step of spray impregnation. Ni source is Nickel acetate. The obtained material is dried at 100°C.

In one of the embodiment, chelating agents is selected from citric acid (CA), glutamic acid (amino acid), Nitriloacetic acid, glutaric acid, succinic acid or combination thereof.
In another embodiment, chelating agents is citric acid (CA) or CA and glutamic acid (Amino acid) or CA and Nitriloacetic acid or CA and Glutaric acid or CA and Succinic acid.
In a preferred embodiment, chelating agent is a combination of glutamic acid and citric acid.
In another embodiment, chelating agents is hexamethylenetetramine or nitrilotriacetic acid or glucaric acids or glutamic acids in combination of CA. Chelating agents can be combination of amine and acid or acid and acid or amino acids and chemical derived acids
Source of tungsten is selected from Ammonium metatungstate or Phoshphotungstic acid. Ni source is Nickel acetate
Catalyst composition comprises Meso Y zeolite 1-10%, NiO-1-5%, WO3-10-25%, SiO2-Al2O3-20-40%, Al2O3-40-60%.

Depolymerization of Lignin
Catalyst sulfided at 350 °C for 20 hours, and lignin feed stock is dissolved in solvents like methanol or ethanol or acetone or ethylene glycol, to obtain a solution with 0.5-2% of lignin content.

Feedstock is kraft lignin, alkali lignin, organosolv lignin, softwood lignin, and hardwood lignin.

The current invention further provides reaction conditions (300 °C – 400 °C, 30-80 bar Pressure, 0.1 - 1 WHSV, H2/feed ratio 50 - 1000 Nm3/m3,) for the single step depolymerization of lignin to fuels/chemicals, by contacting the present invention catalyst.

 
Table 1 summarizes comparative activity of the present catalyst.
Table 1
Catalyst Lignin conversion
% Monomeric products yield
% Dimers
% Oligomers
%
Present invention catalyst with combination of citric acid and glutamic acid 90 60 20-30 10-20
Present invention without any chelating agents 82 52 25-35 16-25
Present invention catalyst with citric acid alone as chelating agent 87 54 23-33 14-24
Present invention with Normal Y zeolite instead of MesoY 80 45 30-40 25-30
NiW based catalyst with Alumina 72 30 40-50 30-40

In a preferred embodiment, catalyst yields 90% lignin conversion and 60% monomer products.

Monomer products are predominantly alkylated benzenes, napthalenes, alkylated phenols, Toluene, Xylenes.

EXAMPLES:
Having described the basic aspects of the present invention, the following non-limiting examples illustrate specific embodiments thereof. Those skilled in the art will appreciate that many modifications may be made in the invention without changing the essence of the invention.

Catalyst Preparation
Preparation of MesoY/SiO2-Al2O3/Al2O3 extrudates
Mesoporous Y Zeolite, SiO2-Al2O3, and Pseudoboehmite alumina are mixed in a kneader and extrudates prepared with 1M Acetic acid solution The obtained extrudates dried at 100 °C and calcined at 500 °C.

Amount of Mesoporous Y Zeolite is 5-20%, SiO2-Al2O3 is 50-80% and Pseudoboehmite alumina is 10-20%, in the extrudates.

Preparation of NiW loaded MesoY/SiO2-Al2O3/Al2O3

 W loading: Using spray impregnation, tungsten and chelating additive components are deposited onto support extrudates. While loading W along with the chelating agents, pH of impregnating solution is between 5-5.2. The obtained material is aged at room temperature and dried at 90 °C, followed by calcination at 500 °C.

 Ni loading: Spray impregnation of Nickel source and chelating agent onto the above obtained material, at a pH of 5. Ni loading is done in single step of spray impregnation. Ni source is Nickel acetate. The obtained material is dried at 100°C.

chelating agent is combination of citric acid (CA) and glutamic acid.
Depolymerization of Lignin

Catalyst sulfided at 350 °C for 20 hours, and kraft lignin is dissolved in solvents like methanol or ethanol or acetone or ethylene glycol, to obtain a solution with 0.5-2% of lignin content. For single step depolymerization, lignin is contacted sulfided catalyst at 330 °C, 60 bar pressure, 1 WHSV and H2/feed ratio of 250 Nm3/m3, and 90% lignin conversion and 60% monomer product yield are obtained.

ADVANTAGES OF THE INVENTION

• Slows down the formation of NiS2 and apparently WS2 forms first followed by nickel substitution at edges.
• High conversion of lignin i.e., ≤ 90% lignin and high yield of monomer products i.e., ≤60%.