(3) Carbonylation of methanol to synthesize formic acidCH,OH +CO → HCOOCH3HCOOCH, +HO → HCOOH +CH3OH(4) Carbonylation and oxidation of methanol to synthesizedimethyl carbonate, dimethyl oxalate or glycol2CH3OH + CO+→CO(OCH3)2+H2O22CH3OH + 2CO +→(COOCH3)2+H2OO(COOCH3)2 + 2H2O --→ (COOH)2 + 2CH3OH(COOCH3)2+4H2→(CH2OH)2+2CH3OH
(3) Carbonylation of methanol to synthesize formic acid (4) Carbonylation and oxidation of methanol to synthesize dimethyl carbonate, dimethyl oxalate or glycol
三、 Catalyst of carbonylation reactionCarbonylation reaction is typical coordination catalyticreaction。Catalyst of carbonylation reaction is complexes formed bytransition metal as central atom (M) with ligard (L)H M, (CO)z Ln X, y, z, n:CoordinationnumberTransitioncentralatomsLigandsRh, Co, Pd etc.Organic phosphorus,iodide ion etc
三、Catalyst of carbonylation reaction Carbonylation reaction is typical coordination catalytic reaction。 Catalyst of carbonylation reaction is complexes formed by transition metal as central atom (M) with ligard (L) Hx My (CO)z Ln Transition central atoms Rh, Co, Pd etc. x, y, z, n: Coordination number Ligands Organic phosphorus、iodide ion etc
8.2 Acetic acid synthesizing from methanol carbonylation,Basicprincipleofaceticacid synthesisfrommethanolcarbonylationMain reactionCat.CH3OH+ COCH,COOHAH=-138.6kJ/molT, PSide reactions2CH,0H CH,0CH, +H,0CH,COOH + CH,OH二 CH,COOCH +H,0CO +H,O CO2 + H2
8.2 Acetic acid synthesizing from methanol carbonylation 一、Basic principle of acetic acid synthesis from methanol carbonylation CH3OH + CO CH3COOH ∆HӨ = -137.9kg/mol Cat. T, P ∆H = -138.6kJ/mol Main reaction Side reactions 2CH3OH CH3OCH3 + H2O CH3COOH + CH3OH CH3COOCH3 + H2O CO + H2O CO2 + H2
Two production methods:CarbonylcobaltismaincatalystHighpressure method:250°C,70MPa (BASFcompany);Methyliodide(iodomethane)ispromoterDiiodo dicarbonyl rhodium is main catalystLow pressure method:180C,3MPa (Monsantocompany)Methyliodide is promoter
High pressure method: 250 ºＣ，70MPa （BASF company); Carbonyl cobalt is main catalyst Methyl iodide (iodomethane) is promoter Diiodo dicarbonyl rhodium is main catalyst Methyl iodide is promoter Low pressure method: 180 ºＣ，3MPa（Monsanto company) Two production methods：
Catalyticmechanismof acetic acid synthesisfrommethanol carbonylation by high pressure method:Catalyst: Co2(CO): / CH,Co2(CO) + H,O +CO-2HCo(CO)4 + CO,CH.OH +HI CHI + H2OHCo(CO)4 H+ + [Co(CO)4][Co(Co)4]: + CH3I :CH3Co(CO)4 + ICH,Co(CO)4 → CH,CO-Co(CO)3CH,CO一Co(CO)3 + CO =CH,CO-Co(CO)4CH,CO-Co(CO)4 + HI --CH,COI + H+ + [Co(Co)4]CH,COI + H,OCH,COOH + HI
▲ Catalytic mechanism of acetic acid synthesis from methanol carbonylation by high pressure method: Catalyst: Co2 (CO)8 / CH3 I Co2 (CO)8 + H2O +CO 2HCo(CO)4 + CO2 CH3OH +HI CH3 I + H2O HCo(CO)4 H+ + [Co(CO)4 ] - [Co(Co)4 ] - + CH3 I CH3Co(CO)4 + ICH3Co(CO)4 CH3CO－Co(CO)3 CH3CO－Co(CO)3 + CO CH3CO－Co(CO)4 CH3CO－Co(CO)4 + HI CH3COI + H+ + [Co(Co)4 ] - CH3COI + H2O CH3COOH + HI