Chemicals from C1 Compounds
- Methane is used in the production of synthesis gas, CO and H2 ,methanol and formaldehyde.
- The largest application of C1 chemistry is the production of methanol
- The use of CO for the preparation of dimethylformamideanddi-methylacetamide
- Synthesis gas refers to a mixtures of hydrogen and carbon monoxide in any proportions.
Synthesis gas is required for a number of petrochemical process such as:
- ✓ Methanol synthesis (using H2 /CO ratio 2/1)
- ✓ Oxosyntheis producing alcohol and aldehydes
- ✓ Manufacturing phosgene and ammonia
- (Fisher–Tropsch)F-T synthesis and synthetic natural gas (CH4 )
Synthesis Gas Production
steam reforming (of natural gas or naphtha) The steam reforming become the primary method .
- Steam reforming gives H2 /CO ratio 2/1 (in case of naphtha),
- 3/1 (in case of natural gas)
partial oxidation (of any of petroleum fractions).
- Partial oxidation of heavy petroleum residues, the H2 /CO ratio falls from 2 to less than 1.
When the synthesis gas (H2 /CO) ratio is (too low), the ratio is adjusted.
- water gas shift” reaction in which CO reacts with the steam to produce hydrogen and carbon dioxide .
- CO +H2O → CO2 + H2 ∆H = -10 Kcal
When the synthesis gas H2 /CO ratio is too high, in case of steam reforming of methane by
- ✓ Adding CO from outside source
- ✓ CO2 is introduced to react with excess H2
- CO2 +3H2 → CH3 OH + H2O
Manufacturing of Synthesis Gas
- 1. Synthesis gas is produced through steam reforming of a desulphurized, light hydrocarbon feedstock (e.g. natural gas CH4 ) and steam.
- 2. The reaction is conducted at pressures up to 40 atm and temperatures of 900-1000 o C, with a supported nickel oxide catalyst in a heated tubular reactor.
- 3. The reaction is endothermic and produces CO and H2 , while the reverse reaction between CO and H2 takes place over nickel catalyst to form CH4 and H2O. CH4 + H2 O ↔ CO + 3H2 ∆H= 50 Kcal (endothermic)
Partial Oxidation of methane
- 1. Oxygen, steam, and methane are fed into a tubular reactor at high temperature and pressure (1300 °C, 40 atm).
- 2. A series of endothermic reactions occur with steam and the partial oxidation of methane.
- 3. The reaction results in the production of CO and H2. CH4 +0.5 O2 → CO + 2H2
- ✓Adhesives and sealant chemicals
- ✓Antifreeze/pipeline dehydration
- ✓Industrial waste treatment agent
- ✓Fuels and fuel additives
- ✓Laboratory chemicals
- ✓Corrosion inhibitors and anti-scaling agents
Methods of Productions
- ✓Catalytic Hydrogenation of CO ( accounts for 75% production)
- ✓Catalytic Hydrogenation CO2 (CO2 + 3 H2 → CH3 OH + H2 O )
- ✓Oxidation of LPG to give oxygenated HC products of which methanol is a major fraction