The Renewable Gas Ask : Part F

Synthetic and renewable fuels are likely to be able to answer both climate change and air pollution concerns, to a greater or lesser extent.

Which gases are best to use for which purpose ? Gases good for combustion release a lot of heat when oxidised. Gases good for trade by liquefaction have boiling points closer to 0° C than further away from it. Simple covalently-bound molecules are most appropriate for reactor chemistry – where transformational reactions are fostered.

Which liquids are best for which application ? Liquids for cleaner combustion are likely to be oxygenate – have oxygen in their formula; and when their thermochemical properties suit the engines they are to be burned in.

Here is a first pass at summarising some of the molecules being investigated – molecules that can be synthesised from basic input chemical feedstocks.

Table : A Selection of Compounds in Industrial Gas and Fuels Chemistry

Note : STP = Standard Temperature and Pressure (20° C to 25° C, at 1 atmosphere of pressure).

Note : DME is here used for Dimethyl ether, and not Dimethoxyethane.

Note : Oxymethylene Dimethyl Ethers are also known as PODE, Polyoxymethylene dimethyl ethers; POMDME or OMDME.

CompoundFormula Boiling Point
(° C)
State (STP)Use
HydrogenH2 -252.87GasFuel, Feedstock
WaterH2O +100LiquidFeedstock
OxygenO2 -182.95GasCombustion
Carbon monoxideCO -191.5GasFuel, Feedstock
Carbon dioxideCO2 -57GasExhaust, Feedstock
AmmoniaNH3 -33.34GasProduct
NitrogenN2 -195.8GasFeedstock
Nitrous oxideN2O -88.46GasExhaust
Nitrogen dioxideNO2 +21.15Liquid/GasExhaust
Nitric oxide, nitrogen monoxideNO -152GasExhaust
MethaneCH4 -161.50GasFuel, Feedstock
EthaneC2H6; H3C-CH3 -88.5GasFuel, Feedstock
PropaneC3H8; H3C-CH2-CH3 -42GasFuel, Feedstock
Butane, n-ButaneC4H10; H3C-CH2-CH2-CH3 -0.5GasFuel, Feedstock
isoButane, 2-MethylpropaneC4H10; H3C-CH(-CH3)-CH3 -11.7GasFuel, Feedstock
Ethene, EthyleneC2H4; H2C=CH2 -103.7GasFeedstock
Propene, Propylene, Methyl ethyleneC3H6; H2C=CH(-CH3) -185.2GasFeedstock
Butene, Butylene, as alpha-ButyleneC4H8; H2C=CH(-CH2CH3) -6.3GasFeedstock
Butene, Butylene, as cis-beta-ButyleneC4H8; H3C-CH=(CH(-CH3)) +2.25, +3.72…GasFeedstock
Butene, Butylene, as trans-beta-ButyleneC4H8; H3C-CH=(CH(-CH3)) +2.25, +3.73…GasFeedstock
Butene, Butylene, as isoButyleneC4H8; H2C=C(-CH3)CH3 -6.9GasFeedstock
Methanol, MeOHCH3OH; H3C-OH +64.7LiquidFuel, Feedstock
Ethanol, EtOHC2H6O; H3C-CH2-OH +78.24LiquidFuel, Feedstock
Propanol, 1-PropanolC3H8O; H3C-CH2-CH2-OH +97 to +98LiquidFuel, Feedstock
isoPropanol, isoPropyl Alcohol, IPA, 2-PropanolC3H8O; H3C-CH(-OH)-CH3 82.6LiquidFuel, Feedstock
Butanol, n-Butanol, 1-Butanol, butan-1-olC4H9OH; H3C-CH2-CH2-CH2-OH +117.6LiquidFuel, Feedstock
sec-Butanol, 2-Butanol, butan-2-olC4H9OH; H3C-CH2-CH(-OH)-CH3 +98 to +100LiquidFuel, Feedstock
isoButanol, 2-methylpropan-1-olC4H9OH; H3C-CH(-CH3)-CH2-OH +107.89LiquidFuel, Feedstock
tert-Butanol, 2-methylpropan-2-olC4H10O; H3C-CH3(-CH3)-OH +82.3LiquidFuel, Feedstock
Methanal, FormaldehydeCH2O; H2C=O +64.7LiquidFeedstock
Dimethyl ether, Methoxymethane, DME, PODE-0, OMDME-0C2H6O; H3C-O-CH3 -24GasFuel, Feedstock
Oxymethylene Dimethyl Ether 1, OME-1, Methylal, Dimethoxymethane,
C3H8O2; H3C-O-CH2-O-CH3 +42, +45.2LiquidFuel, Feedstock
Oxymethylene Dimethyl Ether 2, OME-2, PODE-2, OMDME-2C4H10O3; H3C-O-CH2-O-CH2-O-CH3 +105LiquidFuel
Oxymethylene Dimethyl Ether 3, OME-3, PODE-3, OMDME-3C5H12O4; H3C-O-CH2-O-CH2-O-CH2-O-CH3 +156LiquidFuel
Oxymethylene Dimethyl Ether 4, OME-4, PODE-4, OMDME-4C6H14O5; H3C-O-CH2-O-CH2-O-CH2-O-CH2-O-CH3 +202LiquidFuel
Oxymethylene Dimethyl Ether 5, OME-5, PODE-5, OMDME-5C7H16O6; H3C-O-CH2-O-CH2-O-CH2-O-CH2-O-CH2-O-CH3 +242LiquidFuel
TrioxaneC3H6O3; -CH2-O-CH2-O-CH2-O- +114.5LiquidFeedstock
Diethyl ether, Ether, Ethoxyethane, DEE, OMDEE-0C4H10O; H3C-H2C-O-CH2-CH3 +35LiquidFuel
Oxymethylene Diethyl Ether 1, Diethoxymethane,
Ethylal, DEM, OMDEE-1
C5H12O2; H3C-H2C-O-CH2-O-CH2-CH3 +88LiquidFuel, Feedstock
Oxymethylene Diethyl Ether 2, OMDEE-2C6H14O3; H3C-H2C-O-CH2-O-CH2-O-CH2-CH3 +140LiquidFuel
Oxymethylene Diethyl Ether 3, OMDEE-3C7H16O4; H3C-H2C-O-CH2-O-CH2-O-CH2-O-CH2-CH3 +185LiquidFuel
Oxymethylene Diethyl Ether 4, OMDEE-4C8H18O5; H3C-H2C-O-CH2-O-CH2-O-CH2-O-CH2-O-CH2-CH3 +225LiquidFuel
Dibutyl ether, DBEC8H18O; H3C-H2C-H2C-H2C-O-CH2-CH2-CH2-CH3 +140.8LiquidFuel