The catalytic conversion of 5-hydroxymethylfurfural (HMF) platform compounds has been a popular area of high-value utilisation of lignocellulosic biomass in recent years, and has attracted a lot of attention due to its abundant source and green sustainability.HMF has a variety of reactive functional groups and can be converted by different reactions (e.g. oxidation, reduction, esterification, amination, etc.) into high-value fuels, fuel additives, chemicals, and feedstocks for polymers. In this paper, the reaction mechanisms, catalytic pathways, industrial applications, and techno-economic analyses of various HMF reaction types are discussed, and the current problems and perspectives of HMF conversion are summarised, in the hope that this paper will provide assistance in the development of high-value HMF utilisation. Background Massive consumption of fossil fuels and growing environmental concerns are forcing a search for more sustainable energy resources. Lignocellulosic biomass is a widely available inedible carbon resource in the world that can be converted into renewable energy and high-value chemicals, and biomass-based chemicals can replace the vast majority of petrochemicals. Among them, the catalytic conversion of biomass-derived 5-hydroxymethylfurfural (HMF) platform compounds has been a popular area for high-value utilisation of lignocellulosic biomass in recent years.HMF has multiple functional groups and is prone to multiple side reactions during the conversion process, which affects the quality of chemical products. Therefore, the design and preparation of efficient green catalytic systems to convert HMF into a variety of high value-added chemicals, liquid fuels and additives by selectively breaking/functionalizing the specific functional groups of HMF is the key to realize the high value-added use of HMF. Read more HMF oxidation Firstly, the authors summarised the main products generated by HMF oxidation and mainly discussed three HMF oxidation products 2,5 dicarbonylfuran (DFF), 5-hydroxymethyl-2 furan carboxylic acid (HMFCA) and 2,5 dicarboxylic acid furan (FDCA). The authors systematically introduced the catalyst systems for the selective oxidation of HMF for the preparation of the above three major products, discussing the effects of noble and non-precious metal catalysts, and reaction solvent acidity and alkalinity on the selectivity of the products, respectively. Secondly, the reaction mechanisms of HMF for the preparation of DFF, HMFCA and FDCA were summarised. In addition, the large-scale production of high-value chemicals prepared from HMF oxidation is partially discussed, especially the preparation of FDCA, and its techno-economic analysis is presented. Fig. 1 HMF can be oxidized into many compounds that are obtained from petroleum sources Fig. 2 Possible oxidation mechanism of HMF to DFF over ZnFe_1.65Ru_0.35O₄. (Energy & Fuels, 2017, 31, 533-541.) Fig. 3 Oxidation mechanism of HMF to HMFCA over AgO catalyst in the presence of H₂O₂. (ACS Sustain. Chem. Eng., 2020, 8, 8486-8495.) Fig. 4 Oxidation mechanism of HMF to FDCA over holey Mn₂O₃ nanoflakes. (ChemSusChem, 2020, 13, 548-555) HMF Hydrogenation Firstly, it is summarised that HFM can be hydrogenated to obtain a wide range of high-value chemicals, which can be used as fuels or fuel additives and have properties not inferior to petrochemicals. It focuses on the preparation of DHMF, DHMTHF, and DMF by HMF hydrogenation.Then, it summarises the effects of noble metal catalysts, non-precious metal catalysts, bimetallic catalysts, the nature of the carriers, and the effect of solvents on the HMF hydrogenation products. Due to the growing maturity of HMF to DMF, large-scale preparation of biomass-based DMF is possible. In this paper, examples of large-scale preparation of DMF are also presented and their techno-economics are analysed, indicating that biomass-based DMF has a good prospect for industrial application. Fig. 5 A number of chemicals generated from the selective hydrogenation or hydrogenolysis of HMF. Hydroxyaldol condensation In order to increase the carbon chain of HMF and improve the value of HMF, the aldehyde group of HMF can be used to increase the chain by hydroxyaldol condensation, and then further hydrodeoxygenation to obtain high-quality alkane fuels. This paper introduces the types of hydroxyaldol condensation that can occur in HMF, and takes the hydroxyaldol condensation reaction between HMF and acetone as an example to synthesise C9, C12 and C15 alkanes. The catalysts for hydroxyaldol condensation of HMF are also summarised. Fig. 6 Aldol condensation with acetone followed by hydrogenation and hydrogenolysis. Rehydration Reactions This paper firstly describes the mechanism of the rehydration reaction that occurs in HMF to produce acetylpropionic acid and formic acid. Acetylpropionic acid (LA) is another important biomass platform molecule, the catalytic system for the conversion of HMF to LA is mainly introduced, and the pathways for the conversion of LA to other important chemicals are briefly summarised.GVL is also an important biomass platform molecule, which can be obtained by the conversion of HMF, and the pathways for the conversion of GVL to other chemicals are briefly summarised as well. 7 Horvat's mechanism for HMF decomposition in presence of acid. (Energy & Fuels, 2011, 25, 4745-4755.) Ammoniation The ammoniated products of HMF can be used as important intermediates in chemical and pharmaceutical fields. In this paper, a systematic overview of the ammonification reaction of HMF is given, with special reference to the catalyst types in the ammonification reaction of HMF and the effect of different amines. In addition, the authors summarise the recent progress of polymerisation, etherification and decarboxylation reactions of HMF. 7 Horvat's mechanism for HMF decomposition in presence of acid. (Energy & Fuels, 2011, 25, 4745-4755.) Ammoniation The ammoniated products of HMF can be used as important intermediates in chemical and pharmaceutical fields. In this paper, a systematic overview of the ammonification reaction of HMF is given, with special reference to the catalyst types in the ammonification reaction of HMF and the effect of different amines. In addition, the authors summarise the recent progress of polymerisation, etherification and decarboxylation reactions of HMF.