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Acetic AcidByHamad ShaabiReyan RutherfordShaun LynnAndrew PollockMarketingRegionDemandSupplyImportExportAsia3757-20North America22418-South America22--Europe1114-3Middles East223-20MarketingAcetic acid DerivativesUsesVinyl Acetate MonomerPaints, adhesives, coating, textiles, wire and cable polyethylene compoundsTerephthalic AcidBottles, textiles, polyester fibersAcetate EstersPaints, coating, inks formulation, sealants, adhesives in pharmaceutical applicationsAcetic AnhydrideCellulose acetate fibers, plastics, pharmaceutical such as aspirin OthersChemical reagentMethodEthylene via acetaldehydeMethanol by carbonylationButane by liquid-phase oxidationCativa ProcessEthylene via acetaldehydeReactor 106 C 10 ATMAcetic Acid ColumnAcetaldehyde ColumnAcetic acid ExtractorExtraction SystemFlash tankAcetic Acid scrubberCO2 RemovalOFF GasBFWSteamEthyleneOxygenNitrogenwaterH2OstmstmAcetaldehydeAcetic Acid Product [PdCl4] C2H4 + H2O + O2 CH3CHO + H2O CuCl2 CH3CHO + H2O CH3COOH + H2

Estimating plant capital costs

Major Process Step Special Requirements Score Reaction10 atm (0.3), Temp 160 C(0.3),H.G Stainless steel (0.6) 2.2ScrubberHigh grade s.s. (0.6)1.6CO2 RemovalHigh grade s.s. (0.6)1.6Acetic ColumnHigh grade s.s. (0.6)1.6Acetaldehyde ColumnHigh grade s.s. (0.6)1.6Acetic FinishingHigh grade s.s. (0.6) , entrainment (0.3)1.9Total process complexity factor10.5Methanol CarbonylationMethanol Carbonylation

Most used process for production of Acetic acid.

Developed by Henry Dreyfus at British Celanese, pilot plant opened in 1925.

Uses a metal catalyst, usually Rhodium.

CH3OH + CO CH3COOHMethanol Carbonylation

CH3OH + HI CH3I + H2O

CH3I + CO + [Metal Catalyst] CH3COI

CH3COI + H2O CH3COOH + HICH3OHHICH3IH2OCO + [Metal Catalyst]CH3COICH3COOHH2OHIReaction carried out at a minimum of 200atm.Methanol Carbonylation

Methanol and carbon monoxide are the raw materials.

Bi-products are separated using distillation.

Methanol Carbonylation Flow Diagram

Methanol Carbonylation Complexity Factor

Major Process Step Special Requirements Score Reaction200 atm (0.9)Temp 200 C(0.3)High Grade Stainless steel (0.6) 2.8ScrubberHigh Grade Stainless steel (0.6)1.6CO2 RemovalHigh Grade Stainless steel (0.6)1.6Acetic ColumnHigh Grade Stainless steel (0.6)1.6Acetaldehyde ColumnHigh Grade Stainless steel (0.6)1.6Acetic FinishingEntrainment (0.3)High Grade Stainless steel (0.6) 1.9Total process complexity factor11.1Cativa ProcessCativaDeveloped in 1996 by BP.

Uses Iridium catalyst.

Requires Catalytic Promoter Ruthenium

Increase inactive anionic species Ir(CO2)I3Me]-

1)In I996 a new, more efficient, process for the carbonylation of methanol was announced by BP Chemicals, named the cativa process.2)The caitva process is similar to the monosanto process, however it uses a an iridium catalyst(octahedral), which is much more robust than the rhodium catalyst used by monasanto.3) A substance which, though not itself a catalyst, improves the effectiveness of the catalyst promoters may act chemically or physically.4) The presence of a promoter leads to a substantial increase in the proportion of active anionic species Ir(CO2)I3Me]-

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Mechanism of Iridium Catalysed Reaction

Cativa ProcessFirst step is no longer the rate determining step

Cativa Process 150x faster than Monosanto

Rate = [catalyst] x [CO][I-]

Very high yield 95-98% at 99% purityThe first step is now the fastest step in the reactionThis 150x faster than the monosanto process

18Cativa Flow diagram

Advantages of the Cativa processIridium is much cheaper than rhodium Less iridium is needed because it is so stable that all the catalyst is recycled in the plant The reaction is faster and the quantities of by-products are much lower, reducing the purification costs. For example steam is used to heat the distillation columns and there is a 30% saving of steam over the Monsanto process Some conversion of CO to CO2 still occurs but at a much lower rate CO utilisation is increased from about 85% to over 94% Overall the Cativa process releases about 30% less CO2 per tonne of product than does the rhodium processButane by liquid-phase oxidationAcetic Acid by Butane Oxidation When butane is heated with air in the presence of a metal catalysts acetic acid is produced.C4H10 + 2 O2 2 CH3COOH + H2O

Suitanle metal catalysts are manganese, cobalt and chromium.

Conditions are run at a combination of temperature and pressure designed to be as hot as possible while keeping the butane in a liquid phase. Typical conditions are 150C an 55 atm.

The reaction produces side products such as ethyl acetate, butanone and formic acid which are commercially valuable.

Reaction conditions can be altered to produce either of these as the major product if this is economically useful.

Before methanol carbonylation became commercialised in the 1980s, Butane oxidation was the major source of acetic acid

Now produces less than 10% of acetic acid supply annually.

Thank you any question ?References:G. James, chemical process and design hand book, USA 2001A. John & Encyclopedia of chemical technologyullmanns & encyclopedia of industrial chemistry