In general the present invention concerns a method for conversion of particular 4-alkyl-2- hydroxyphenols (e.g. 4-n-propyl-2-hydroxyphenol, 4-ethyl-2-hydroxyphenol) and 4-alkyl-2- alkoxyphenols (e.g. 4-/7-propyl-2-methoxyphenol, 4-ethyl-2-methoxyphenol or 4-n-propyl-2- ethoxyphenol) into 3-alkylphenols. More specifically, this invention relates to a novel process of selectively forming meta-alkyl phenols of various alkylphenols, such as for instance converting the fraction of 4-alkyl-2-hydroxyphenols and 4-alkyl-2-alkoxyphenols into high yields of 3-alkylphenols (Fig.l).

BACKGROUND

Lignocellulose biomass is a highly abundant and potentially low cost renewable feedstock to produce heat, power, fuels, chemicals and materials as an alternative for fossil resources (M. Dusselier, M. Mascal and B. Sels, in Selective Catalysis for Renewable Feedstocks and Chemicals, ed. K. M. Nicholas, Springer International Publishing, 2014, vol. 353, ch. 544, pp. 1- 40; J. S. Luterbacher, D. Martin Alonso and J. A. Dumesic, Green Chem., 2014, 16, 4816-4838).

Lignocellulose is composed of three main constituents, cellulose, hemicellulose and lignin. Until recently, lignocellulose biorefineries have mainly focused on the valorization of (hemi)cellulose, while lignin was regarded as a side product and mostly used as energy source (by burning) (J. Zakzeski, et al., Chem Rev., 2010, 110, 3552-3599). Only a minor amount of lignin is used for material applications (dispersants, emulsifiers,...) or in the production of chemicals like vanillin (J. Lora, in Monomers, Polymers and Composites from Renewable Resources, ed. M. N. B. Gandini, Elsevier, Amsterdam, 2008, pp. 225-241; J. Bozell, in Selective Catalysis for Renewable Feedstocks and Chemicals, ed. K. M. Nicholas, Springer International Publishing, 2014, vol. 353, ch. 535, pp. 229-255). There is however a growing consensus that lignin valorization is essential to the environmental sustainability and economics of a lignocellulosic biorefinery (A. J. Ragauskas, er al., Science, 2014, 344, 709). Lignin constitutes the largest direct source of renewable aromatic/phenolic compounds on Earth and is regarded as a promising feedstock for a wide variety of bulk and fine chemicals, as well as fuels.

The most important lignin depolymerization methods are pyrolysis, base-catalyzed depolymerization, hydrogenolysis, liquid-phase reforming, chemical oxidation and gasification, usually yielding moderate amounts (< 20 wt%) of numerous monomeric compounds (C. Xu, R.A.D. Arancon, J. Labidid and R. Luque, Chem. Soc. Rev. 2014, 43, 7485- 7500). Very promising routes for lignin depolymerization are reductive methods like hydrogenolysis and liquid-phase reforming, resulting in phenolic monomer-yields up to 55 wt% (J. M. Pepper and W. Steck, Can. J. Chem., 1963, 41, 2867-2875; J. . Pepper, P. Supathana, Can. J. Chem., 1978, 56, 899-902; N. Yan, C. Zhao, P. J. Dyson, C. Wang, L. T. Liu and Y. Kou, Chemsuschem, 2008, 1, 626-629; C. Li, M. Zheng, A. Wang and T. Zhang, Energy Environ. ScL, 2012, 5, 6383-6390; Q. Song, F. Wang, J. Y. Cai, Y. H. Wang, J. J. Zhang, W. Q. Yu and J. Xu, Energy Environ. Sci., 2013, 6, 994-1007). The phenolic compounds obtained from these processes possess unique chemical structure features. The phenolic entity bears one or two methoxy groups, next to a 4-alkyl chain. Use of such 4-alkylguaiacols (4-alkyl-2- methoxyphenols) and 4-alkylsyringols (4-alkyl-2,6-dimethoxyphenols) as intermediates for high-value target chemicals and polymer building blocks has thus far received only little attention. Until now, main research goals have focused on upgrading the lignin-derived compounds to hydrocarbon fuels or aromatics by complete removal of oxygen through hydrodeoxygenation (HDO).

A possible processing of the phenolic compounds into useful products is its conversion into alkylphenois. Therefore, the methoxy group(s) should be removed (demethoxylation). Direct demethoxylation yields 4-alkylphenols (N. Joshi, A. Lawal, Ind. Eng. Chem. Res. 2013, 52, 4049- 4058). However, a challenge is the production of 3-alkylphenols or m-alkylphenols since these are very interesting chemicals used in various applications. 3-ethylphenol is an intermediate for the production of photochemicals and a possible intermediate for the production of pharmaceuticals and agricultural chemicals (Fiege, H., Voges, H.-W., Hamamoto, T., Umemura, S., Iwata, T Miki, H., Fujita, Y Buysch, H.-J., Garbe, D. and Paulus, W. 2000. Phenol Derivatives. Ullmann's Encyclopedia of Industrial Chemistry). 3-ethylphenol and 3-n-propylphenol are potent tsetse fly attractants (C. H. Green, in Advances in Parasitology, eds. R. M. J.R. Baker and D. Rollinson, Academic Press, 1994, vol. Volume 34, pp. 229-291; E. Bursell, AJ.E. Gough, P.S. Beevor, A. Cork, D.R. Hall, G.A. Vale, Bull. ent. Res. 1988, 78, 281-291; M.L.A. Owaga, A. Hassanali, P.G. McDowell, Insect Sci. Applic. 1988, 9, 95- 100; G.A. Vale, D.R. Hall, AJ.E. Gough, Bull. ent. Res. 1988, 78, 293-300). Tsetse flies are the main vector of African sleeping sickness (trypanosomiasis), and therefore several tsetse control methods are developed to monitor, reduce or even eradicate local populations of targeted tsetse species (R. Brun, J. Blum, F. Chappuis, C. Burri, Lancet, 2010, 375, 148-159.; I. Ujvary, G. Mikite, Org. Process Res. Dev., 2003, 7, 585). The use of traps baited with natural of artificial host odours is an environmentally benign tsetse control method. 3-n-propylphenol is used extensively in artificial odour baits, mostly together with acetone, p-cresol and 1-octen- 3-ol. 3-n-propylphenol can also be used in antimicrobial compositions for treatment and prevention of disease in mammals (J.G. Holwerda, B.D. Levine, US 20050165104 Al). 3- alkylphenols like 3-methylphenol, 3-ethylphenol and 3-n-propylphenol represent leather- and ink-like odor notes, as well as having a medicinal smell (M. Czerny, et al., Chem. Senses, 2011, 539-553). 3-alkylphenols like 3-ethylphenol, 3-n-propylphenol and 3-n-butylphenol can also be used as perfuming ingredients to improve the odour of perfuming compositions having an oud character (E. Delort, J. Limacher, Oud Odorants, US 20140371121 Al).

3-ethylphenol or m-ethylphenol is conventionally produced by sulfonation of ethylbenzene at high temperature (150-210 °C) to form an isomeric mixture of ethylbenzenesulfonic acids rich in the m-isomer (o/m/p ratio: 1.5/58.5/39.2), followed by selective hydrolysis of the o- and p- isomers back to ethylbezene and sulfonic acid by blowing steam through the mixture (o/m/p ratio: 0.8/95.7/2.3), and alkali fusion of the remaining m-ethylbenzenesulfonic acid (o/m/p ratio: 0.9/95.7/2.6) (Taoka Chemical Co., EP0080880 / JP 59 108 730 / JP 59 076 033). This process results in a 72% ethylphenol yield on ethylbenzene basis. This process has many problems such as tedious multi-step operation, inferior operational surroundings associated with handling of dangerous high-temperature sulfuric acid and sodium hydroxide, corrosion of equipment caused by the use of sulfuric acid, and disposal of waste water containing sulfuric acid and alkali (Maruzen Petrochemical Co., EP0296582). A variation of the desulfonation step, involving the addition of steam to the mixture of sulfonic acid in an excess in relation to the amount of evaporable water, in which the formed ethylbenzene is removed from the reaction mixture, makes it possible to obtain a higher m/p-ratio of the ethylphenols (Kemira Agro Oy, EP0694516).

3-ethylphenol can also be obtained through alkylation of phenol with ethylene or ethanoi over a crystalline aluminosilicate (H-ZSM-5/AI2O3) at high temperature (400 °C), yielding an isomeric mixture of ethylphenols rich in the m-isomer (S ₀ /m/ _P : 23.3/39.8/13.1% for ethylene alkylation at 50.2% phenol conversion and 23.8/39.2/13.5% for ethanoi alkylation at 48% phenol converson), followed by selective dealkylation of the o- and p-isomers over a specific crystalline aluminosilicate catalyst (Mg-P-ZSM-5/AI ₂ 03 or Si-P-ZSM-5/AI ₂ 0 ₃ ) at high temperature (450 °C) (Maruzen Petrochemical Co., EP0296582). Dealkylation with Mg-P-ZSM- 5/AI2O3 of the m/p-ethylphenol mixture after ethylene alkylation yields a S ₀ /m/ _P of 0.1/67.7/0.9% and a m-ethylphenol recovery of 90.4%. With Si-P-ZSM-5/AI ₂ 0 ₃ , a S ₀ /m/ _P of 0.1/68.2/1.0% and a m-ethylphenol recovery of 91.1% is obtained.

Mixtures of m- and p-ethylphenol can be obtained from the alkylation of phenol or from distillation of high-temperature bituminous coal tar. However, since these compounds have very similar boiling points, separation by distillation is not possible (Fiege, H., Voges, H.-W., Hamamoto, T., Umemura, S., Iwata, T., Miki, H., Fujita, Y., Buysch, H.-J., Garbe, D. and Paulus, W. 2000. Phenol Derivatives. Ullmann's Encyclopedia of Industrial Chemistry). Next to the separation method described in EP0296582, other separation methods like those used for the separation of m- and p-cresol can be applied, e.g. crystallization, adsorption, separation via addition compounds or via ester or salt formation, etc. (Fiege, H. 2000. Cresols and Xylenols. Ullmann's Encyclopedia of Industrial Chemistry).

Several routes are described for the synthesis of 3-n-propylphenol: reductive deoxygenation of 3-hydroxypropiophenone (Hartung, W. H.; Crossley, F. S. J. Am. Chem. Soc. 1934, 56, 158.), reductive deoxygenation of safrole or isosafrole (Henrard, J. T. Chem. Zentralbl. 1907(11), 78, 1512.; Cousin, S. G., Lions, F. J. Proc. R. Soc. N. S. W. 1937, 70, 413; Strunz, G. M., Court, A. S. J. Am. Chem. Soc. 1973, 95, 3000.), Wittig reaction of 3-hydroxybenzaldehyde with ethyl(triphenyl)phosphonium bromide (Bursell, E., Gough, A. J. E., Beevor, P. S., Cork, A., Hall, D. R., Vale, G. A. Bull. Entomol. Res. 1988, 78, 281.), C-C coupling of 3-bromoanisole and ethyl halide (Hassanali, A., McDowell, P. G., Owaga, M. L. A., Saini, R. K. Insect Sci. Its Appl. 1986, 7, 5.), cyclocondensation of 3-oxohexanal with 1,3-acetonedicarboxylic acid esters (Prelog, V., Wursch, J., Konigsbacher, K. Helv. Chim. Acta 1951, 34, 258.), catalytic carbanionic ethylation of m-cresol (Steele, B.R., Villalonga-Barber, C, Micha-Screttas, M., Screttas, C.G., Tetrahedron Lett. 2006, 47, 2093), Grignard reaction of 3-benzyloxybenzaldehyde with ethylmagnesium bromide and subsequent reductive deoxygenation of the secondary alcohol (Carvalho, C. F., Sargent, M. V. J. Chem. Soc, Perkin Trans. 1 1984, 1621.) and Grignard reaction of 3- hydroxybenzaldehyde with ethylmagnesium bromide followed by reductive deoxygenation of the secondary alcohol (I. Ujvary, G. Mikite, Org. Process Res. Dev., 2003, 7, 585). Most of these routes however require expensive or toxic (even forbidden) substrates and include multistep reactions with waste-intensive key steps.

Two recently developed synthesis routes involve anacardic acid derivatives (salicylic acids with saturated and mono, di an tri-unsaturated C15 side chains in the 6-position) extracted from cashew nut shells as feedstock. In the first synthesis route, the anacardic acid is heated in a graphite bath to produce cardanol (3-(pentadec-8-enyl)phenol), which is subsequently converted via carbon-carbon double bond isomerisation, metathesis with 2-butene and hydrogenation, resulting in a relatively low yield of 3-n-propyphenol of 11% based on cardanol (Mmongoyo, J.A., Mgani, Q.A., Mdachi, S.J.M., Pogorzelec P.J., Cole-Hamilton, D.J., Eur. J. Lipid Sci. Technol., 2012, 114, 1183-1192). In the second synthesis route, anacardic acid is first converted to 3-(non-8-enyl)phenol through ethenolysis and distillation, followed by isomerizing cross-metathesis with short-chain olefins and hydrogenation (S. Baader, P.E. Podsiadly, D.J. Cole-Hamilton, L.J. Goossen, Green Chem. 2014, 16, 4885-4890). In the latter synthesis route, both 3-ethyl- and 3-n-propylphenol can be produced in a combined yield of 85% based on the anacardic acids in a 1:1.3 ratio when ethylene is used during the cross- metathesis. If an extra cross-metathesis step with 2-butene is applied, 3-n-propylphenol can be obtained in a total yield of 69% based on the anacardic acids. An extra cross-metathesis step with ethylene yields 3-ethylphenol in a yield of 84% based on anacardic acids. Although this last synthesis route results in high product yields of the 3-alkylphenols starting from a renewable substrate, the fact that it is a multistep process using expensive Ru- and Pd-based homogeneous catalysts and ethylene, 2-butene and hydrogen as extra reagents hinders its application on a large scale. A particular embodiment of present invention concerns obtaining 4-alkyl-2-alkoxyphenols from lignin using a heterogeneous metal catalyst and selective conversion of 4-alkyl-2- alkoxyphenols towards a mixture of 3-alkylphenols like 3-ethylphenol and 3-n-propylphenol.

4-alkyl-2-alkoxyphenol conversion ranges in mole percent are more than 80%, preferably more than 90%. The yield in mole percent for 3-alkylphenols in the range of 50 to 90%, preferably within the range of 60 to 90%.

Next to 3-alkylphenol, also a small amount of 4-alkylphenol can be obtained, but the 3- and 4- alkylphenols can be separated trough the processes described earlier. The selectivity for such 3-alkylphenol in mole percent is typically less than 22%, preferably less than 12%.

SUMMARY OF THE INVENTION Certain 4-alkyl-2-hydroxyphenols and 4-alkyl-2-alkoxyphenols like 4-ethyl-2-hydroxyphenol, 4-/7-propyl-2-hydroxyphenol, 4-ethyl-2-methoxyphenol and 4-n-propyl-2-methoxyphenol can be obtained from the depolymerisation of lignin.

The present invention describes a particular catalytic process for the production of 3- alkylphenol from such 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol, in which the alkyl substituent is for instance methyl, ethyl or n-propyl. This process of present invention comprises the conversion of the 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol to 3- alkylphenol in the presence of a redox catalyst at elevated temperature under a hydrogen atmosphere. In one embodiment the redox catalyst preferably comprises a noble metal (Pt, Ru, ...) or base metal (Ni, Cu,...) supported on a support of which a considerable part is composed of T1O2. In yet a more preferred embodiment, the Ti02 support is composed of the anatase crystal phase. Most preferably the metal loading on the support ranges from 0.1 to 30 wt% and is preferably between 0.5 and 6 wt%. The reaction is preferably carried out at temperatures between 200 °C and 400 °C and with an hydrogen pressures between 0.5 bar and 100 bar. An embodiment of present invention describes a process for the production of 3-alkylphenol from such 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol _; in which the alkyJ substituent is for instance methyl, ethyl or n-propyl. This process of present invention comprises the conversion of the 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol to 3-alkylphenol at elevated temperature in the presence of a redox catalyst and a hydrogen donating species. In this embodiment the reaction is preferably carried out at temperatures between 200 °C and 400 °C.

Another particular embodiment concerns a catalytic process of selectively forming meta-alkyl phenol from 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol comprising: supplying a) a 4- alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol in fluid form and b) a redox catalyst into a reaction vessel or a continuous reactor setup under hydrogen pressure and energizing or heating such reaction medium thus inducing conversion of 4-alkyl-2-hydroxyphenol or 4-alkyl- 2-alkoxyphenol to meta-alkyl phenols. The fluid form a 4-alkyl-2-hydroxyphenol or 4-alkyl-2- alkoxyphenol can be a gas fluid or a liquid form. The 4-alkyl-2-hydroxyphenol or 4-alkyl-2- alkoxyphenol can be solved in an organic fluid. In this embodiment the redox catalyst preferably comprises a noble metal (Pt, Ru, ...) or base metal (Ni, Cu,...) supported on a support of which a considerable part is composed of T1O2. In the preferred embodiment, the T1O2 support is composed of the anatase crystal phase. The metal loading on the support ranges from 0.1 to 30 wt% and is preferably between 0.5 and 6 wt%. The reaction is preferably carried out at temperatures between 200 °C and 400 °C and hydrogen pressures between 0.5 bar and 100 bar.

Another particular embodiment of present invention concerns a catalytic process of selectively forming meta-alkyl phenol from 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol comprising comprising: supplying a) a 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol comprising, b) a hydrogen donating solvent and c) a redox catalyst into a reaction vessel and energizing or heating such reaction medium thus inducing conversion of 4-alkyl-2- hydroxyphenol or 4-alkyl-2-alkoxyphenol to a meta-alkyl phenols. In this embodiment the redox catalyst preferably comprises a noble metal (Pt, Ru, ...) or base metal (Ni, Cu,...) supported on a support of which a considerable part is composed of T1O2. In the preferred embodiment, the T1O2 support is composed of the anatase crystal phase. The metal loading on the support ranges from 0.1 to 30 wt% and is preferably between 0.5 and 6 wt%. The reaction is preferably carried out at temperatures between 200 °C and 400 °C.

Another particular embodiment of present invention concerns a catalytic process of selectively forming meta-alkyl phenol from 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol comprising comprising: supplying a) a solvent medium, b) a 4-alkyl-2-hydroxyphenol or 4- alkyl-2-alkoxyphenol, c) a hydrogen donating species and d) a redox catalyst into a reaction vessel and energizing or heating such reaction medium thus inducing conversion of 4-alkyl-2- hydroxyphenol or 4-alkyl-2-alkoxyphenol to a meta-alkyl phenols. In this embodiment the redox catalyst preferably comprises a noble metal (Pt, Ru, ...) or base metal (Ni, Cu,...) supported on a support of which a considerable part is composed of T1O2. In the preferred embodiment, the T1O2 support is composed of the anatase crystal phase. The metal loading on the support ranges from 0.1 to 30 wt% and is preferably between 0.5 and 6 wt%. The reaction is preferably carried out at temperatures between 200 °C and 400 °C. The present invention relates to a catalytic process for converting a 4-R2-2-RiO-phenol for instance a 4-alkyl-2-hydroxyphenol or a 4-alkyl-2-alkoxyphenol (e.g. 4-n-propyl-2- hydroxyphenol, 4-ethyl-2-hydroxyphenol, 4-n-propyl-2-methoxyphenol, 4-ethyl-2- methoxyphenol or 4-n-propyl-2-ethoxyphenol), comprising: supplying 1) said 4-R2-2-R1O- phenol and 2) a hydrogen donating solvent, species or a hydrogen atmosphere and 3) a redox catalyst comprising anatase titanium dioxide (Ti02) and redox metal into a reaction vessel and 4) energizing or heating such medium thus inducing conversion of 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol into a 3-alkylphenol, with the 4-alkyl-2-alkoxyphenol or 4-alkyl-2- hydroxyphenol having one of the following structure:

A wherein in structure A (phenolic monomer) Rl is H or CnH2n+l with n = 1, 2 or 3 and R2 is CnH ₂ n+l with n = 1, 2, 3 or 4 or CnH2nOH with n = 1, 2, 3 or 4 or CnH ₂ n-10 with n = 1, 2, 3 or 4 or CnH ₂ n-l with n = 2, 3 or 4.

A further embodiment concerns a catalytic process for the production from 4-alkyl-2- hydroxyphenols and 4-alkyl-2-alkoxyphenols under hydrogen atmosphere of corresponding 3- alkylphenols, with the 4-alkyl-2-hydroxyphenols and 4-alkyl-2-alkoxyphenols having the following structure:

A

a) wherein in structure A (phenolic monomer) Rl is H or CnH ₂ n+l with n = 1, 2 or 3 and R2 is CnH ₂ n+l with n = 1, 2, 3 or 4 or CnH ₂ nOH with n = 1, 2, 3 or 4 or CnH ₂ n-10 with n = 1, 2,3 or 4 or CnH ₂ n-l with n = 2, 3 or 4.

b) wherein the molar yield of the 3-alkyl phenol is at least 40%;

c) wherein the molar ratio of formed 3-alkyl phenol to 4-alkyl phenol is at least

Yet another embodiment of present invention concerns a catalytic process for converting a 4- R2-2-R10-phenol for instance a 4-alkyl-2-hydroxyphenol or a 4-alkyl-2-alkoxyphenol, comprising: supplying 1) said 4-R2-2-RiO-phenol and 2) a hydrogen donating solvent, species or a hydrogen atmosphere and 3) a redox catalyst comprising anatase titanium dioxide (Ti02) and redox metal into a reaction vessel and 4) energizing or heating such medium thus inducing conversion of 4-alkyl-2-hydroxyphenol or 4-alkyl-2-alkoxyphenol into a 3-alkylphenol, with the 4-alkyl-2-alkoxyphenol or 4-alkyl-2-hydroxyphenol having one of the following structure:

B C

a. wherein in structures B or C (phenolic dimer or oligomer containing substructures of 4-alkyl-2-alkoxyphenols or 4-alkyl-2-hydroxyphenols) Rl is H or CnH2n+l with n = 1, 2 or 3 and R3 is H, CH ₃ or CH ₂ OH and R4 is H or CnH ₂ n+l with n = 1, 2, 3 or 4 or CnH ₂ nOH with n = 1, 2, 3 or 4 or CnH ₂ n-10 with n = 1, 2, 3 or 4 or CnH2n-l with n = 2, 3 or 4 or a structure containing a similar substructure of 4-alkyl-2-alkoxyphenols and R5 is H or OH or OCnH2n+l with n = 1, 2 or 3 or a structure containing a similar substructure of 4-alkyl-2- alkoxyphenols.

b. Wherein the molar yield of the 3-alkyl phenol is at least 40%;

c. Wherein the molar ratio of formed 3-alkyl phenol to 4-alkyl phenol is at least 3.5; A further more particular embodiment concerns catalytic process for the production from 4- alkyl-2-hydroxyphenols and 4-alkyl-2-alkoxyphenols under hydrogen atmosphere of corresponding 3-alkylphenols, with the 4-alkyl-2-hydroxyphenols and 4-alkyl-2-alkoxyphenols having the following structure:

B C a. wherein in structures B or C (phenolic dimer or oligomer containing substructures of 4-alkyl-2-hydroxyphenols and 4-alkyl-2-alkoxyphenols) Rl is H or CnH2n+l with n = 1, 2 or 3 and R3 is H, CH3 or CH ₂ OH and R4 is H or CnH ₂ n+l with n = 1, 2, 3 or 4 or CnH ₂ nOH with n = 1, 2, 3 or 4 or CnH ₂ n-l with n = 2, 3 or 4 or a structure containing a similar substructure of 4-alkyl- 2-alkoxyphenols and R5 is H or OH or OCnH2n+l with n = 1, 2 or 3 or structure containing a similar substructure of 4-alkyl-2-alkoxyphenols.

In another aspect, the present invention provides a catalytic process for the production from 4-alkyl-2,6-dihydroxyphenols, 4-alkyl-2-hydroxy-6-alkoxyphenols and 4-alkyl-2,6- dialkoxyphenols under hydrogen atmosphere of corresponding 3-alkylphenols, with the 4- alkyl-2,6-dihydroxyphenols, 4-alkyl-2-hydroxy-6-alkoxyphenols and 4-alkyl-2,6- dialkoxyphenols having the following structure:

B C

a. Wherein in structure A (phenolic monomer) Rl is H or CnH ₂ n+l with n = 1,

2 or 3 and R2 is CnH ₂ n+l with n = 1, 2, 3 or 4 or CnH ₂ nOH with n = 1, 2, 3 or 4 or CnH ₂ n-10 with n = 1, 2,3 or 4 or CnH ₂ n-l with n = 2, 3 or 4 and R3 is H or CnH ₂ n+l with n = 1, 2 or 3.

b. Wherein in structures B or C (phenolic dimer or oligomer containing substructures of 4-alkyl-2,6-dihydroxyphenols, 4-alkyl-2-hydroxy-6- alkoxyphenols and 4-alkyl-2,6-dialkoxyphenols) Rl is H or CnH2n+l with n = 1, 2 or 3, R3 is H or CnH ₂ n+l with n = 1, 2 or 3 and R4 is H, CH ₃ or CH ₂ OH and R5 is CnH ₂ n+l with n = 1, 2, 3 or 4 or CnH ₂ nOH with n = 1, 2, 3 or 4 or CnH ₂ n-l with n = 2, 3 or 4 or a structure containing a similar substructure of 4-alkyl-2-alkoxyphenols and R6 is H or OH or OCnH ₂ n+l with n = 1, 2 or

3 or structure containing a similar substructure of 4-alkyl-2-alkoxyphenols. c. Wherein the molar yield of the 3-alkyl phenol is at least 40%; d. Wherein the molar ratio of formed 3-alkyl phenol to 4-alkyl phenol is at least 3.5;

Some of the techniques described above may be embodied as a catalytic process according to any one of these previous embodiments, whereby the support for the metal is a carbon support or inorganic support, whereby the support comprises titanium dioxide anatase whereon a redox metal. It is also desirable that the process is catalysed by a redox catalyst containing a support that comprises anatase titanium dioxide and a metal on said support in the range of 0.01 to 30 wt%, preferably between 0.1 and 6 wt%. In more specific embodiments thereof the Ti0 ₂ is or comprises crystallized as nano-crystalline anatase and/or the T1O2 is or comprises nanotubes in anatase phase and/or the ΤΊΟ2 has hollow structures, for instance in the form of hollow ΤΊΟ2 shells or of mesoporous ^" ΠΟ2 and/or the ^" ΠΟ2 is crystallized as nano-crystalline anatase powder with high specific surface area, up to 250 m ² /g _> preferably up to 335 m ² /g and/or the catalyst comprises of a redox metal on a support, with the support mainly comprising Ti0 ₂ , which is at least for a considerable part in the anatase phase and/or titanium dioxide includes at least 80 wt. % anatase phase, and most preferably about 82.8 wt. % to 100 wt. % anatase phase and/or the metal component is selected from Co, Ni, Ru, Rh, Pd, Re, Os, Ir, Pt, Cu and/or mixtures and/or combinations thereof or the metal component is selected from Pd, Pt, Ru, Ni, Cu, and/or mixtures and/or combinations thereof or the metal component is selected from the group consisting of P, V, Sn, Cu, Ni, Co, and Fe and/or mixtures and/or combinations thereof or yet more specific the metal component is comprises a noble metal such as Pt and Ru or a base metal such as Ni and Cu and/or the carbon support or inorganic support component comprises at least one of AI2O3, S1O2, Zr02, and/or mixtures and/or combinations thereof and/or the carbon support or inorganic support comprises a semi-conductive material such as T1O2, ZnO, CeC>2, Zr02, SrTi03, CaTiC>3, and BaTi03, or mixtures thereof (e.g., composite semiconductors such as TiCh/CeCh, TiC /ZrCh) and/or the carbon support or inorganic support comprises a metal oxide or an alloy oxide of titanium alloyed with iron, aluminium, vanadium, or molybdenum. Some of the techniques described above may be embodied with the specific features that the amount of the carbon support or inorganic support component is in a range from 1 wt % to 50 wt % of the total weight of the catalyst.

Some of the catalytic process described above may be also embodied with the specific features that the carbon support or inorganic support component comprises AI203 and/or S1O2.

Some of the catalytic process described above may be also embodied with the specific features that the inorganic oxide has a micro structure in which a crystalline phase and an amorphous phase are present together. Some of the catalytic process described above may be also embodied with the specific features that the amount of the carbon support or inorganic support component is in a range from 1 wt % to 50 wt % of the total weight of the catalyst. Some of the catalytic process described above may be also embodied with the specific features that carbon support or inorganic support component has an average particle size in a range from 1 μηι to 70 μηι.

Some of the catalytic process described above may be also embodied with the specific features that the amount of the metal component is in a range from 0.01 wt % to 30.0 wt % of the total weight of the catalyst.

Some of the catalytic process described above may be also embodied with the specific features that at least 50 wt % of the metal component is distributed on the carbon support or inorganic support component.

Some of the catalytic process described above may be also embodied with the specific features that the catalyst is comprised in a molecular sieve. Some of the catalytic process described above may be also embodied with the specific features that the to be converted starting material is in a fluid phase.

Some of the catalytic process described above may be also embodied with the specific features that fluid is a liquid or that fluid is a gas.

Some of the catalytic process described above may be also embodied with the specific features that the reaction temperature is in the range between 200°C and 500°C, preferably between 250°C and 400°C. Some of the catalytic process described above may be also embodied with the specific features that the hydrogen pressure is in the range between 0.5 to 150 bars, preferably between 1 to 100 bars. ILLUSTRATIVE EMBODIMENTS OF THE INVENTION Sources of lignocellulose biomass include bagasse (sugarcane, sweet sorghum,...), barley straw, wheat straws (wheat, barley, rice,...), stover (corn, milo,...), softwood (spruce, pine,...), hardwood (birch, poplar,...), switch grass (Panicum virgatum) and elephant grass.

Definitions

3-alkylphenols are defined as structures comprising a phenolic unit with a substituent in respectively the 3- or meto-position. 4-alkylphenols are defined as structures comprising a phenolic unit with a substituent in respectively the 4- or para-position.

4-alkyl-2-hydroxyphenols and 4-alkyl-2-alkoxyphenols can be obtained through various lignin processing techniques like pyrolysis, acid- or base-catalyzed depolymerization, oxidation, liquefaction or hydroprocessing methods like hydrogenolysis or liquid-phase reforming.

4-alkyl-2,6-dihydroxyphenols, 4-alkyl-2,6-alkoxyphenols and 4-alkyl-2-hydroxy-6- alkoxyphenols can also be obtained through various processing techniques. These compounds are transformable through the proposed catalytic process. A possible structure of these compounds and their products are shown in Fig. 2 In these structures, Rl is H or Cnhhn+l with n = 1, 2 or 3 and R2 is CnH2n+l with n = 1, 2, 3 or 4 or CnH ₂ nOH with n = 1, 2, 3 or 4 or CnH2n- 10 with n = 1, 2,3 or 4 or CnH2n-l with n = 2, 3 or 4 (Fig. 2) "Product yield" is defined as the molar amount of product formed per molar amount of starting substrate and "Substrate conversion" is defined as the molar amount of substrate converted per molar amount of starting material. Product selectivity is defined as the ratio of the product yield over the substrate conversion. For instance a particular embodiment context "Conversion" means the mole percent of the initial alkylphenol that is reacted to form a different compound, not necessarily all the desired product, while "Yield" is the mole percent of the converted starting material that forms any meta-alkyl phenol (m-alkylphenol) and "Selectivity" is the mole percent of the reaction product formed that is meta-alkyl phenol. For example, if 10 moles of alkylphenol are reacted and 2 moles of alkylphenol are left unchanged, then the conversion is 80 percent. If the reaction product contains 6 moles of meta-alkyl phenol then the yield is 60 percent and the selectivity is 75 percent. The process can be conducted under hydrogen pressure or in a hydrogen-donating solvent or in the presence of hydrogen-donating species. Under hydrogen pressure means that hydrogen gas is present. Hydrogen-donating solvents or hydrogen-donating species are all species (A) that have the ability to donate hydrogen with transformation into an oxidized form (A _ox ). A -> xH ₂ + Aox (with x > 1)

Solvents or species that are known to be able to donate hydrogen are for example alcohols like methanol, ethanol, / ^' sopropanol, etc., acids like formic acid, acidic acid, etc. or hydrocarbons like 9,10-dihydroanthracene, tetralin, etc.

Next to phenolic monomers like the 4-alkyl-2-alkoxyphenols, also phenolic dimers and oligomers containing 4-alkyl-2-alkoxyphenol and 4-alkyl-2,6-dialkoxyphenol substructures are formed in the reaction (S. Van den Bosch, W. Schutyser, R. Vanholme, T. Driessen, S.-F. Koelewijn, T. Renders, B. De Meester, W. J. J. Huijgen, W. Dehaen, C. M. Courtin, B. Lagrain, W. Boerjan and B. F. Sels, Energy Environ. Sci., 2015, DOI: 10.1039/c5ee00204d; J. C. del Rio, J. Rencoret, A. Gutierrez, L Nieto, J. Jimenez-Barbero and A. T. Martinez, Journal of Agricultural and Food Chemistry, 2011, 59, 11088-11099). In this case, the 4-alkyl chain of the 4-alkyl-2-hydroxyphenol, 4-alkyl-2-alkoxyphenol, 4-alkyl-2,6-dihydroxyphenol or 4-alkyl-2,6- dialkoxyphenol is incorporated into another structure. Possible structures of phenolic dimers and their products are shown in Fig. 3. In these structures, Rl is H or CnH ₂ n+l with n = 1, 2 or 3 and R2 is H, CH ₃ or CH ₂ OH and R3 is H or CnH ₂ n+l with n = 1, 2, 3 or 4 or CnH ₂ nOH with n = 1, 2, 3 or 4 or CnH ₂ n-10 with n = 1, 2, 3 or 4 or CnH2n-l with n = 2, 3 or 4 or a structure containing a similar substructure of 4-alkyl-2-alkoxyphenols and R4 is H or OH or OCnH2n+l with n = 1, 2 or 3 or a structure containing a similar substructure of 4-alkyl-2-alkoxyphenols and R5 is H or CnH ₂ n+l with n = 1, 2 or 3 (Fig. 3). The molar ratio of formed 3-alkylphenol to 4-alkylphenol is defined as the ratio of the molar amount of the 3-alkylphenol to the molar amount of 4-alkylphenol formed during reaction. Since 3- and 4-alkylphenols usually have very similar boiling points (Fiege, H., Voges, H.-W., Hamamoto, T., Umemura, S., Iwata, T., Miki, H., Fujita, Y., Buysch, H.-J., Garbe, D. and Paulus, W. 2000. Phenol Derivatives. Ullmann's Encyclopedia of Industrial Chemistry; Fiege, H. 2000. Cresols and Xylenols. Ullmann's Encyclopedia of Industrial Chemistry), a derivatisation treatment might be required to separate the alkylphenols during gas chromatographic analyses (F. Orata, in Advanced Gas Chromatography - Progress in Agricultural, Biomedical and Industrial Applications (Ed.: M. A. Mohd), Intech, 2012).

Next to 3-alkylphenol and 4-alkylphenol, also other products like methylated alkylphenols, alkylcyclohexanones, alkylcyclohexane and alkylbenzene are obtained in the reaction. A mixture of 3- and 4-alkylphenol can be isolated via distillation, column chromatography or other separation processes and 3- and 4-alkylphenol can further be separated from one another (Fiege, H., Voges, H.-W., Hamamoto, T., Umemura, S., Iwata, T., Miki, H., Fujita, Y., Buysch, H.-J., Garbe, D. and Paulus, W. 2000. Phenol Derivatives. Ullmann's Encyclopedia of Industrial Chemistry; Fiege, H. 2000. Cresols and Xylenols. Ullmann's Encyclopedia of Industrial Chemistry). A catalyst suitable for present invention can be prepared by deposition of the redox metal on the catalyst support. Various methods are available to deposit a redox metal on a support, like impregnation by soaking, incipient wetness impregnation, precipitation-deposition, ion- exchange, gas phase deposition, etc. (Haber, J., Block, J. H. and Delmon, B. 2008. Methods and Procedures for Catalyst Characterization. Handbook of Heterogeneous Catalysis. 3.3.2:1230- 1258). After impregnation of the redox metal, the obtained catalyst precursor can undergo several pretreatment steps like drying, calcination and reduction, before use in the reaction.

A redox metal suitable for present invention can be a metal, or a mixture of metals, that is able to generate and donate active hydrogen species. A redox metal comprises a metal selected from the group of Fe, Co, Ni, Cu, Ru, Rh, Pd, Ir, and Pt and mixtures thereof. Titanium is widely distributed and occurs primarily in the minerals anatase, brookite, ilmenite, perovskite, rutile and titanite (sphene) (Emsley, John (2001). "Titanium". Nature's Building Blocks: An A-Z Guide to the Elements. Oxford, England, UK: Oxford University Press). Anatase (alias octahedrite) T0 ₂ is like rutile TO2 a more commonly occurring modification of titanium dioxide. Anatase is always found as small, isolated and sharply developed crystals and it crystallizes in the tetragonal system. The common pyramid of anatase, parallel to the faces of which there are perfect cleavages, has an angle over the polar edge of 82°9', the corresponding angle of rutile being 56°52 But crystals of anatase can be prepared in laboratories by chemical methods such as sol-gel method. Examples include controlled hydrolysis of titanium tetrachloride (TiCU) or titanium alkoxides. The vertical axis of the crystals is longer than in rutile. Other important differences between the physical characters of anatase and rutile are that the former is less hard (5.5-6 vs. 6-6.5 Mohs) and dense (specific gravity about 3.9 vs. 4.2). Also, anatase is optically negative whereas rutile is positive. For comparison, the refraction index (n) in descending order for several materials follows: rutile (n=between 2.61-2.89); anatase (n=between 2.48-2.56); diamond (n=between 2.41-2.43); gahnite (n=between 1.79-1.82); sapphire (n=between 1.75-1.78); cordierite (n=between 1.52- 1.58); beta-spodumene (n=between 1.53-1.57); and residual glass (n=between 1.45-1.49). Also for comparison, the birefringence (DELTA n) in descending order for some of the same materials follows: rutile (DELTA n=between 0.25-0.29); anatase (DELTA n=0.073); sapphire (DELTA n=0.008); cordierite (DELTA n=between 0.005-0.017); diamond (DELTA n=0); and gahnite (DELTA n=0). Based on the above data, it can be seen that some of the Ti-containing crystalline phases, and rutile in particular, are among the materials exhibiting some of the highest refractive indices. In addition, it can be seen that some of the Ti-containing crystalline phases, and rutile in particular, have a relatively high birefringence (DELTA n), a result of the anisotropic character of their tetragonal crystal structure.

A catalyst support suitable for present invention is composed for a considerable part (> 80 wt%) of T1O2 in the anatase phase. As known by the experts, the concentration of T1O2 anatase in the support can also be related to the surface concentration to which the reagents have access to, meaning that coating of a non-Ti02 support with T1O2 anatase, so that the surface of the support is composed for a considerable part of T1O2 anatase, is also included. In the process of the invention, the reaction temperature depends on the nature and the catalytic activity of the specific catalyst, on the thermal stability of the specific catalyst and on the boiling point of the solvent. The reaction is usually carried out between 200 and 400 °C, preferably between 275 and 325 °C.

The reaction can be carried out in a suitable solvent which does not deactivate the catalyst, is stable under reaction conditions and does not adversely affect the reaction in any way. The solvent choice depends further on the substrate solubility. Preferred solvents include, but are not restricted to, n-heptane, n-hexadecane and n-propylcyclohexane.

ABBREVIATONS

4-AG 4-alkyl-2-methoxyphenol or 4-alkylguaiacol

4-PG 4-n-propyl-2-methoxyphenol or 4-n-propylguaiacol

4-EG 4-ethyl-2-methoxyphenol or 4-ethylguaiacol

4- EC 4-ethyl-2-hydroxyphenol or 4-ethyl-l,2-dihydroxybenzene or 4-ethylcatechol

5- AG 5-alkyl-2-methoxyphenol or 5-alkylguaiacol

3- APh 3- or m-alkylphenol

4- APh 4- or p-alkylphenol

MeAPh Methylalkylphenol

ACHol/one alkylcyclohexanol and alkylcyclohexanone

MeOACHol methoxyalkylcyclohexanol

EXAMPLE 1

This example illustrates the preparation of the metal on support catalysts. A 3ΝΠΊΟ2ΑΙ catalyst was prepared by incipient wetness impregnation of 2 g T1O2 powder (Alfa Aesar, catalyst support, 150 m ² /g, 100% anatase) with 1.5 mL of an aqueous solution of 0.7 M Ni(N0 ₃ )2.6H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

EXAMPLE 2 This example illustrates the derivatisation procedure of the reaction product. Before analysis of the reaction product by gas chromatography, a derivatisation treatment by trimethylsylilation was performed to enable separation of the 3- and 4-alkylphenols. 0.5 mL of the reaction product, 0.5 mL pyridine (Acros, 99+%) and 0.25 mL N-methyl-N- (trimethylsilyl)trifluoroacetamide (Sigma Aldrich, 97+%) were combined in a vial and placed in an oven at 80 °C for 30 min.

EXAMPLE 3

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3ΝΠΊΟ2ΑΙ catalyst. The reactor was flushed with N ₂ , heated to 300 °C and put under constant H2 pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 4

609 mg (4 mmol) 4EG (Sigma Aldrich, 98+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3NiTi02Al catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H2 pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 5

609 mg (4 mmol) 4EC (Sigma Aldrich, 98+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3NiTi02Al catalyst. The reactor was flushed with l\ , heated to 300 °C and put under constant H2 pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature, diethylether was added to the reactor ensure complete solubilisation of all compounds (4EC is only weakly soluble in hexadecane), and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 6

A 3ΝΠΊ02Α2 catalyst was prepared by incipient wetness impregnation of 2 g Ti0 ₂ powder (Sachtleben Chemie GmbH, HOMBIKAT M 311, ~ 300 m ² /g, 100% anatase) with 4.2 mL of an aqueous solution of 0.25 M Ni(N0 ₃ )2.6H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3ΝΠΊΟ2Α2 catalyst. The reactor was flushed with N ₂ , heated to 300 °C and put under constant H2 pressure at 2 MPa H ₂ . The stirrer speed was set at 750 rpm. After 2 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

COUNTER EXAMPLE 1

A 3NiZr02 catalyst was prepared by incipient wetness impregnation of 2 g ZrC powder (Alfa Aesar, catalyst support, 90 m ² /g) with 1.23 mL of an aqueous solution of 0.86 M Ni(N0 ₃ )2.6H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3NiZr02 catalyst. The reactor was flushed with N ₂ , heated to 300 °C and put under constant H2 pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 1 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1. COUNTER EXAMPLE 2

A 3NiTi02RU catalyst was prepared by incipient wetness impregnation of 2 g Ti0 ₂ powder (Sachtleben Chemie GmbH, ~ 100 m ² /g, 100% rutile) with 1.92 mL of an aqueous solution of 0.55 M Ni(N0 ₃ )2.6H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3NiTi02RU catalyst. The reactor was flushed with N ₂ , heated to 300 °C and put under constant H ₂ pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 2 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1. COUNTER EXAMPLE 3

A 3NiTi02ARU catalyst was prepared by incipient wetness impregnation of 2 g T1O2 powder (Evonik Industries, Aeroxide ^® Ti0 ₂ P25, ~ 35-65 m ² /g, mixture of anatase and rutile) with 1.9 mL of an aqueous solution of 0.55 M Ni(N03)2.6H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H2-flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3NiTi02ARU catalyst. The reactor was flushed with N ₂ , heated to 300 °C and put under constant H2 pressure at 2 MPa H ₂ . The stirrer speed was set at 750 rpm. After 1 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 7

A O.5RUT1O2AI catalyst was prepared by incipient wetness impregnation of 2 g T1O2 powder (Alfa Aesar, catalyst support, 150 m ² /g, 100% anatase) with 1.5 mL of an aqueous solution of 0.067 M Ru(NH ₃ ) ₆ CI ₃ (Acros Organics), drying the sample at 60 °C for 12 h _; calcination of the sample at 400 °C for 1 h under N ₂ -flow and reduction of the sample at 400 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the O.5RUT1O2AI catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H2 pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 8

A 0.5PtTiO2Al catalyst was prepared, by incipient wetness impregnation of 2 g Ti0 ₂ powder (Alfa Aesar, catalyst support, 150 m ² /g _/ 100% anatase) with 1.5 mL of an aqueous solution of 0.018 M Pt(NH ₃ ) ₄ Cl ₂ H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h, calcination of the sample at 400 °C for 1 h under 0 ₂ -flow and reduction of the sample at 400 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 0.5PtTiO ₂ Al catalyst. The reactor was flushed with N ₂ , heated to 300 "C and put under constant H ₂ pressure at 2 MPa H ₂ . The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 9

A 3CuTi0 ₂ Al catalyst was prepared by incipient wetness impregnation of 2 gTi0 ₂ powder (Alfa Aesar, catalyst support, 150 m ² /g, 100% anatase) with 1.5 mL of an aqueous solution of 0.24 M Cu(N03) ₂ 3H ₂ 0 (Sigma Aldrich), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3CuTi0 ₂ Al catalyst. The reactor was flushed with N ₂ , heated to 300 °C and put under constant H ₂ pressure at 2 MPa H ₂ . The stirrer speed was set at 750 rpm. After 6 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

COUNTER EXAMPLE 4 A ^" Π02Α1 catalyst was prepared by drying the T1O2 powder (Alfa Aesar, catalyst support, 150 m ² /g, 100% anatase) at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ - flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the ΤΪ02Α1 catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H2 pressure at 2 MPa H ₂ . The stirrer speed was set at 750 rpm. After 1 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 10

A 0.5ΝΓΠΟ2Α1 catalyst was prepared by incipient wetness impregnation of 2 g T1O2 powder (Alfa Aesar, catalyst support, 150 m ² /g _/ 100% anatase) with 1.5 mL of an aqueous solution of 0.11 M Ni(N0 ₃ ) ₂ .6H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the Ο.5ΝΠΊΟ2ΑΙ catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H ₂ pressure at 2 MPa H ₂ . The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 11

A 6ΝΠΊ02Α1 catalyst was prepared by incipient wetness impregnation of 2 g T1O2 powder (Alfa Aesar, catalyst support, 150 m ² /g, 100% anatase) with 1.5 mL of an aqueous solution of 1.44 M ϊ( θ3)2·6Η2θ (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 6ΝΠΊΟ2ΑΙ catalyst. The reactor was flushed with N2, heated to 300 "C and put under constant H2 pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

COUNTER EXAMPLE 5

A 12ΝΓΠΟ2ΑΙ catalyst was prepared by incipient wetness impregnation of 2 g T1O2 powder (Alfa Aesar, catalyst support, 150 m ² /g, 100% anatase) with 1.5 mL of an aqueous solution of 3.08 Ni(N0 ₃ ) ₂ .6H ₂ 0 (Alfa Aesar), drying the sample at 60 °C for 12 h and reduction of the sample at 500 °C for 1 h under H ₂ -flow.

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 12ΝΓΠΟ2ΑΙ catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H2 pressure at 2 MPa H ₂ . The stirrer speed was set at 750 rpm. After 1 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 12

665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 100 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 0.2 g of the 3ΝΠΊ02Α1 catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H2 pressure at 6 MPa H2. The stirrer speed was set at 750 rpm. After 2 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 13

4000 mg (24 mmol) 4PG (Sigma Aldrich, 99+%), 300 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL hexadecane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with l g of the 3NiTi0 ₂ A2 catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H2 pressure at 6 MPa H2. The stirrer speed was set at 750 rpm. After 2 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.

EXAMPLE 14 665 mg (4 mmol) 4PG (Sigma Aldrich, 99+%), 300 mg decane (Sigma Aldrich, 99+%, internal standard) and 20 mL n-propylcyclohexane solvent (Sigma Aldrich, 99%) were placed in a 50 mL autoclave, together with 1 g of the 3NiTi02A2 catalyst. The reactor was flushed with N2, heated to 300 °C and put under constant H2 pressure at 2 MPa H2. The stirrer speed was set at 750 rpm. After 4 h reaction, the reactor was cooled down to room temperature and the reaction mixture was analysed. The catalytic results are shown in Table 1.