Phenolderived Products from Fast Pyrolysis of Organosolv Lignin

Phenol-derived Products from Fast Pyrolysis of Organosolv Lignin Kanit Soongprasit, Ph. D Assoc. Prof. Viboon Sricharoenchaikul, Ph. D Duangduen Atong, Ph. D National Metal and Materials Technology Center (MTEC) Faculty of Engineering, Department of Environmental Engineering, Chulalongkorn University

OBJECTIVE • Production of phenol-derived chemicals from organosolv lignin was studied using the Py-GCMS technique • The effect of pyrolysis temperature (400, 500, 600, and 700°C) on the selectivity of phenolic compounds • A conceptual guideline for further studies on the chemical upgrading process to high-valued biochemical platform and building block

Background: Lignin & phenolic compound Lignin: • The largest aromatic bio-polymer feedstock • 15– 30% of plants in terms of dry weight and 40% in terms of energy • Potential of being refined for aromatic chemical platform • Organosolv process for lignin extraction Lignin valorization: • Pyrolysis and gasification • Modification and functionalization macromolecule • Biochemical Phenolic compound: soxygenated-alkyl methoxy phenol, alkyl phenol, phenol

Experimental: Sample preparation Sugarcane bagasse (BG) Dried Pulverized Sieved (125– 425µm) Organosolv lignin extraction process 1. Autogenous conditions with Et. OH and H 2 O in the ratio 75: 25 2. 10 g of BG was physically mixed and soaked with the extracting agent 3. The mixing precursor was poured into a 50 ml PTFE- stainless steel autoclave 4. Hot air oven at a temperature of 180ºC for 3 hours 5. Filtered using a filter paper with 5– 13 µm pore diameter 6. Dried at 60ºC Analyzer technique: • Thermogravimetric analyzer (METTLER TOLEDO; TGA 2). • Fourier-transform infrared spectroscopy (Perkin Elmer; Spectrum Spotlight 300; FTIR) • Nuclear magnetic resonance spectroscopy (BRUKER; AV 500; NMR).

Experimental: Study on phenol production using Py-GCMS technique Py-GCMS system 0. 4 mg of lignin • • Temperature: 400, 500, 600, and 700ºC Carrier gas: Helium at 5 ml/min (99. 999%) 30 seconds collect a split ratio of 1: 100 Identify chemical compound at a mass-to-charge ratio (m/z) of 20– 800 at a 70 e. V • Scan speed 625 amu/s Criteria: Pyrolyzed products selectivity Phenol products identification • • Pyrolyzer (Frontier; Py-2020 id) with an auto-shot sampler (Frontier; AS 1020 E) Gas chromatography unit (Thermo Scientific; TRACE 1300) Mass spectrophotometer detector (Thermo Scientific; ISQLT Low-polarity capillary column (TG-1701 MS; 30 m x 0. 25 mm; 0. 25 mm film thickness; Thermo Scientific)

Experimental: Study on phenol production using Py-GCMS technique Criteria for pyrolyzed products selectivity. Categories Compound Number of Structure/Functional group Aromatic-OH Aromatic-OCH 3 Example Hydroxyphenyl (H-unit) Products with hydroxyphenyl unit 1 1 0 Phenol, 3 -methyl- Guaiacyl (G-unit) Products with guaiacyl unit 1 1 1 Guaiacol, Vanillin Syringyl (S-unit) Products with syringyl unit 1 1 2 Syringol Aliphatic (Ali-HC) Hydrocarbon with aliphatic structure 0 0 0 Butane Aromatic (Aro-HC) Hydrocarbon with aromatic structure ≥ 1 0 0 Benzene, Toluene O-compound (O-comp) O-containing compound 0 0 0 Ester, Carboxylic acid Criteria for phenol products identification. Categories Compound Example Oxygenated-alkyl methoxy phenol (OR-Ph-OCH 3) Phenol compound with oxygen containing group along with methoxy group Vanillin and Phenol, 4 -(3 -hydroxy-1 -propenyl)-2 methoxy- Alkyl methoxy phenol (R-Ph-OCH 3) Phenol compound with alkyl group along with methoxy group Phenol, 4 -ethyl-2 -methoxy- and Phenol, 2 -methoxy-3 -(2 -propenyl)- Methoxy phenol (Ph-OCH 3) Phenol compound with methoxy group Phenol, 2 -methoxy- and Phenol, 2, 6 -dimethoxy- Alkyl phenol (R-Ph) Phenol compound with alkyl group Phenol, 3 -methyl- and Phenol, 3, 4 -dimethyl- Phenol (Ph) Phenol without alkyl and methoxy group Phenol

Results and Discussion: Lignin characteristics Chemical composition of raw lignin Thermal decomposition under inert (N 2) atmosphere %Weight Comm-OS-lignin Composition Moisture Comm. OSBG-lignin 5. 69 3. 78 Volatile matter 56. 91 67. 34 Fixed carbon 36. 35 28. 80 Ash 1. 05 0. 09 BG-lignin

Results and Discussion: Lignin characteristics FTIR spectra of Comm-OS-lignin and BG-lignin

Results and Discussion: Lignin characteristics 1 H-NMR of raw lignin.

Results and Discussion: Fast pyrolysis of lignin using Py-GCMS Chromatogram of pyrolyzed products Comm-OS-lignin BG-lignin • Most of the phenolic compound selectivity obtained from Comm-OSlignin and BG-lignin through fast pyrolysis at 400– 600ºC • Formation of methoxy phenol and alkylated phenol temperature 700ºC, the phenol yield lower than 8%.

Results and Discussion: Fast pyrolysis of lignin using Py-GCMS Chemical selectivity of the pyrolyzed products from Comm-OS-lignin Chemical selectivity of the pyrolyzed products from BG-lignin Distribution of H-unit, G-unit, and S-unit of the pyrolyzed products

Results and Discussion: Fast pyrolysis of lignin using Py-GCMS Phenolic selectivity of pyrolyzed products of Comm-OS-lignin Phenolic selectivity of pyrolyzed products of BG-lignin • Temperature is a key player of phenolic selectivity • Cleavage of methoxy and others aromatic substitution groups

Results and Discussion: Fast pyrolysis of lignin using Py-GCMS Total phenol production from lignin • Partial decomposition of suspected phenol compound • Total phenol production - BG-lignin: 58. 47% (400ºC) to 37. 88% (700ºC) - Comm-OS-lignin: 53. 35% (400ºC) to 39. 23% (700ºC) • Alkyl phenol 23. 38% • Abundance of Alkyl phenol selectivity: - Aromatic side chains: oxygencontaining group, alkyl group, and methoxy group

Conclusion • Bagasse from the local industry as raw materials (BG-lignin) evaluated with commercial organosolv lignin (Comm-OS-lignin) • BG-lignin exhibited in term of volatile organic compounds (VOCs) and fixed carbon of 93. 26% and 96. 14% • BG-linin significantly lower ash of 0. 09% • Highest degree of Comm-OS-lignin and BG-lignin degradation at a temperature of about 350ºC • Demethoxylation reaction of methoxy group of G-unit and S-unit, high temperature that results in a vastly enhanced H-unit and slightly on aromatic hydrocarbon products • A higher pyrolysis temperature of 700ºC, the elimination of aromatic side group and promoted alkyl phenol selectivity • Selective catalysts, such as vanillin, BTX, and other aromatics, upgrade the valued chemical production for chemistry industrial, food, pharmaceutical, and cosmetic industries.