Michele Aresta ^** e-mail: cheam@nus.edu.sg, michele.aresta@uniba.it

Department of Chemical and Biomolecular Engineering, National University of Singapore, 119077 Singapore, Singapore

Consorzio Interuniversitario Reattività Chimica e Catalisi (CIRCC), via Celso Ulpiani 27, 70126 Bari, Italy

Angela Dibenedetto

Consorzio Interuniversitario Reattività Chimica e Catalisi (CIRCC), via Celso Ulpiani 27, 70126 Bari, Italy

Dipartimento di Chimica, University of Bari, 70126 Bari, Italy

Michele Aresta is IMM Chair at the NUS, Singapore. Expert on carbon dioxide utilization in synthetic chemistry, catalysis, biomass conversion, coordination and metallorganic chemistry. He was founder of the International Conference on Carbon Dioxide Utilization (ICCDU) and is now Honorary Chair. He received the Renoir Prize for the diffusion of scientific knowledge, the Award of the Italian Chemical Society for his work on "Carbon Dioxide Activation", was appointed Honorary Professor at the University of Tianjin, and he received the Award of the Societé Française de Chimie for Inorganic Chemistry. Author of over 250 papers published in international journals, and of several reviews on CO₂utilization. Editor of seven books on CO₂utilization.

Angela Dibenedetto is a Professor at the Department of Chemistry, University of Bari (UNIBA), Italy. Her scientific interests are focused on carbon dioxide utilization in synthetic chemistry, catalysis, coordination chemistry and organometallic chemistry, green chemistry, marine biomass as source of fuels and chemicals applying the biorefinery concept. She is director of the Interuniversity Consortium on Chemical Reactivity and Catalysis. She was the winner of the RUCADI Prize for "Better Carbon Management – An Intelligent Chemical Use of CO₂" delivered by ACP (Belgium), Carburos Metalicos (Spain) and ENIChem (Italy). Author of over 90 scientific papers published in international journals since 1995 and several book chapters.

Property	Methane	Ethane	Propane	Propene	Butane	Natural Gas	Tail gas
Molecular mass	16.04	30.07	44.10	42.08	58.12	Mixture	Mixture
Melting point / °C	-182.4	-182.8	-187.6	-185	-138.2	-187.6/-182.4	-187.6/-182.4
Boiling point / °C	-161.5	-88.6	-42.1	-48	-0.5	-161.5/-6.2	-161.5/-6.2
H₂O sol, 25 °C / (mg L^-1)	22	60.2	62.4	200	61.2	22/221	22/221

Property	CH₃COOH	CH₃CH₂COOH	CH₃CH(COOH)CH₃	CH₃(CH₂)₂COOH	C5 acid
Melting point / °C	17	-21	-47	-7.9	-34.5
Boiling point / °C	118	141	155	163.5	186
	CH₃OH	CH₃CH₂OH	CH₃CH₂CH₂OH	CH₃CH(OH)CH₃	CH₃(CH₂)₂CH₂OH
Boiling point / °C	64.7	78.4	96	82	118

Technology	Pros	Cons
Solid phases	Low loss	Energy consumption
Liquid phases (LP) MEA	Mature	Loss, volume
Membranes (M)	Reduced volume-space	Cost, life-time
Combined (LP/M)	Efficiency	Volume, cost
Cryogenic	Low emission	Cost, use of electricity
Issues: CAPEX, OPEX, energetic costs (energy penalty: 20-40+%)

Industrial sector	Mt_CO2 y^-1 produced
Oil refineries	850-900
Ethene and other petrochemical processes	155-300
LNG sweetening	25-30
Ethene oxide	10-15
Ammonia	160
Fermentation	> 200
Iron and steel	ca. 900
Cement	> 1000

	Short term (2030)	Medium term (2050)	Long term (> 2050)
Chemistry	Oil and gas dominate	Oil and gas	Oil and gas
	Biomass will grow	Coal will re-enter with clean technologies	Coal will be used with clean technologies
		Biomass will reach its maximum	CO₂ will be recovered and used on a large scale
		CO₂ will be used
Energy	Mix of fossils	Switch to perennial	Substantial grow of perennial
	Wind will grow	Solar will continue to grow and spread	Electricity will play a key role also in the transportation sector
	Solar will grow		Fuels produced from water and CO₂ will share an important part of the market

Starting material	Product	Catalyst	Solvent	T / K	Yield / %	Selectivity / %
Cellulose	5-HMF	ZrO₂/TiO₂	MIK	-	87	35
Cellulose	Levulinic acid	H₂SO₄ (1.5-3%)	H₂O	-	-	70-80
Glucose	5-HMF	H⁺	Water	> 373	30-60	20-50
Glucose	5-HMF	Acid resins	Water	373-473	30-60	20-40
Glucose	5-HMF	Al/Mg hydrotalcite Amberlist-15	Water	^-	60	76
Fructose	5-HMF	H-form zeolites	Water	-	60	53
Fructose	-	-	DMSO/MIK/BuOH	-	90	89
Fructose	γ-Valerolactone	Ru/C	H₂O	450	80	62
5-HMF	Furanics (HMF ethers, esters)	Various	Alcohol/organic acids	> 373	Variable	Variable

Catalyst	Media, supports or co-catalysts	Oxidant	Products
Laccase (multi-Cu enzyme)	Associated HRP (iron protoporphyrin)	O₂ (Laccase) H₂O₂ (HRP)	Oxidized lignine
Co-immobilized laccases and HPR	Clay	O₂, H₂O₂	Oxidized depolymerized lignine
Mn(TMePyP)/clay/HBT (clay-PMS). The Fe analogue can also be used	Hydroxybenzotriazole or veratrilic alcohol	H₂O₂	Oxidized oligomers, and monomers
Co, Cu, Mn(Salen) complexes	Inorganic acids, PPh₃, ethylendiamine	O₂ or H₂O₂	Oxidized monomers from dimers
Polyoxometalates Mo(VI), W(VI), V(V), Nb(V): XM'_aM"_12-aO^bm- Keggin anions	SiO₂	O₂ or H₂O₂	Oxidized monomers and parent oligomers
O₃ReCH₃	Polymeric ligands: poly-4-vinylpyridine and its N-oxide	H₂O₂	Oxidized monomers and parent oligomers

Brasil

Catalysis for the Valorization of Low-Value C-Streams