The authors report (a) hydrothermal liquefaction (HTL) of lignocellulosic biomass using homogeneous nitrate salt catalyst: Ni(NO
3)
2, Ca(NO
3)
2, Co(NO
3)
2 and Fe(NO
3)
3 for the production of carboxylic acid enriched biocrude, and (b) detailed investigation of biocrude generated from a biomass emphasizing on the selectivity of lactic acid in particular and (c) study of the possible reaction pathways for production of carboxylic acids, biocrude and bio-oil with their energy content from a biomass. A biomass was loaded in the high temperature high pressure SS316 reactor and HTL of biomass was performed at 200
o- 300
oC. During HTL reaction, liquid samples were withdrawn at regular time intervals and the processed slurry was centrifuged to recover biocrude and residue. The biocrude was further analyzed by TOC analyzer, GC-MS and HPLC. The biocrude and residue obtained were further extracted in different solvents followed by evaporation on Rota evaporator to recover bio-oil and the bio-oil was analyzed using GC-MS. The HPLC analysis of biocrude revealed the presence of sugars, C
1-C
3 carboxylic acids such as lactic, propionic, acetic and formic, HMF/furfural and other oxygenated compounds.
Among different C
1-C
3 acids, lactic acid was observed in the major amount of 83.92 wt% using pinewood: solvent of 1:75 at 250
oC. The results obtained on carboxylic acid enriched
biocrude, bio-oil composition, selectivity of organic acids such as lactic acid obtained during HTL of biomass substrates and possible reaction pathways will be presented in detail.
