Table T able of Contents Identication of Product Chemistry, Properties, Uses, World Market and Projected Market Groth!!!!!!!!!!!!!!! Groth!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!! " #cetic acid properties!!!!!!!!!!!!!!!! properties!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! " Methanol Carbonylation $Monsanto process%!!!!!!!!!!!!!!!! process%!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!& !!!!!!!!!!!!!!!!!& 'eferences!!!!!!! 'eferences!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!! (
)
Identifcation o Product Chemistry, Properties, Uses, World Market and Projected Market Growth
#cetic acid properties #cetic acid is a clear colourless li*uid that is +ery corrosi+e and has a noticeable odour! The odour can be detected hen concertation is as lo as )ppm! # table summarisin the physical properties is belo#cetic #cid
#ppearance Molecular eiht 9oilin point Meltin point Critical temperature Critical pressure apour density >iscosity "1:C .olubility in ater .td! enthalpy of formation ?f /"2( .td! enthalpy of combustion ?c/"2( .td! molar entropy .:"2(
Colourless li*uid ith stron odour 34!41 8mol ))(:C )3!1:C &;0:C 1;!(13kpa $1;)!)atm% 1;:C 03&:C )402 k8m& )400!3 k8m& "!4; )!413 mPa5s soluble 50(&!)3 kj mol 5) 5(;1!1 kj mol5) )1(!4 kj5) mol5)
Perry’s chemical n!ineerin! hand"ook #ntoine Constants or C p $%&'mol(
.pecic /eat Capacities Componen c) c" c& t #cetic #cid )&2304 5&"!( 4!2 Usin e*uation Cp6 C) 7C"T7C&T "7 C0T&7C0T0 "
c0
c1
4
4
Methanol Carbonylation $Monsanto process% #cetic #cid manufactured +ia carbonylation of Methanol Monsanto process uses a homoeneous catalyst hich is usually a 'hodium5based catalyst! The main reactions that take place inside the reactor and in the presence of the catalyst are as follos@
C/&A/ 7 /I B C/ &I 7 /"A C/&I 7 CA B C/ &CAI C/&CAI 7 /"A B C/&CAA/ 7 /I
$)% $"% $&%
The process characteristically takes place at a hih pressure and temperature hich are in the reion of beteen )45&4 bar and );15"44:C! Usin a Methyl Iodine $C/ &I% 'hodium comple as a catalyst is the most common type catalyst used for this process as it achie+es a +ery hih con+ersion rate of around 22D from the methanol at the temperatures and pressures discussed abo+e! # study of the reaction kinetics shos that the methanol reaction is a Eero order reaction hile the rhodium and iodide promoter are both rst order reactions! The most dominant side reaction that occurs in this process, is the production of methyl acetate hich can be a +aluable side product if etracted and separated from the main product or can be easily recycled to dri+e don runnin costs! The production of methyl acetate is e*uilibrium limited and +aries and chanes ith any temperature or pressure chane!! The reaction that occurs to produce methyl acetate is as follos@ C/&A/ 7 C/&CAA/ F C/ &CAAC/& 7 /"A $0% $esterication reaction%
&
#n assumption can be made that all methyl acetate that does make it back into the reactor +ia the recycle streams ill react ith any of the ater that is and that around 14D of the unreacted methanol lea+in the reactor then reacts to form methyl acetate! Ather by products produced durin the process are- dimethyl ether, methyl acetate, acetoaldehyde, butyraldehyde, ethyl acetate and propinoic acid!
0
$Ullmanns, "44&, p! )12%
1
a% b% c% d% e%
'eactor
To bein the process Methanol and compressed Carbon monoide $&4 bar to ensure the reaction occurs in the li*uid phase% enter a spared tubular reactor under the reaction conditions mentioned abo+e $)45&4 bar and beteen );15"44:C% in order for the reaction to occur! The reaction is hihly eothermic and therefore a coolin mechanism for the rector such as a coolin jacket is needed to ensure a stable temperature is kept and the ecess heat is remo+ed! The hydrocarbon +apour stream eitin the top of the reactor is mainly composed of unreacted asses and can be easily reco+ered usin a scrubber for recyclin! The resultant reacted miture $+apour phase% is then epanded by the use of a Hasher or turbine to reco+er duty to compress air for use in the reactor and to also reco+er any of the catalyst hich is then sent back to the reactor! The Hasher condenses the hydrocarbons and the liht hydrocarbons are then separated by the subse*uent column to a cut point of (4:C and either recycled or sent to storae for further treatment and separation! The lo boilers that are separated are dimethyl ether, methyl acetate, acetaldehyde, butyraldehyde and ethyl acetate! The 'emainin miture from the column alon ith the main product is then sent throuh to the
a% b% c% d% e%
'eactor
To bein the process Methanol and compressed Carbon monoide $&4 bar to ensure the reaction occurs in the li*uid phase% enter a spared tubular reactor under the reaction conditions mentioned abo+e $)45&4 bar and beteen );15"44:C% in order for the reaction to occur! The reaction is hihly eothermic and therefore a coolin mechanism for the rector such as a coolin jacket is needed to ensure a stable temperature is kept and the ecess heat is remo+ed! The hydrocarbon +apour stream eitin the top of the reactor is mainly composed of unreacted asses and can be easily reco+ered usin a scrubber for recyclin! The resultant reacted miture $+apour phase% is then epanded by the use of a Hasher or turbine to reco+er duty to compress air for use in the reactor and to also reco+er any of the catalyst hich is then sent back to the reactor! The Hasher condenses the hydrocarbons and the liht hydrocarbons are then separated by the subse*uent column to a cut point of (4:C and either recycled or sent to storae for further treatment and separation! The lo boilers that are separated are dimethyl ether, methyl acetate, acetaldehyde, butyraldehyde and ethyl acetate! The 'emainin miture from the column alon ith the main product is then sent throuh to the dehydration column $d%, in hich the top oranic layer taken from the column is +ery rich in hydrocarbons and is sent back to the reactor for recyclin! The bottoms a*ueous layer from the dehydration column is distilled to reco+er the hydrocarbons and then also recycled back to the reactor! The remainin hydrocarbon free product consists of +olatile oyenated deri+ati+es $aldehydes, ketones, esters and alcohols%, ater, +olatile monocarboylic acids $formic, acetic, propinoic and butyric from butane%, and a miture of non5+olatile materials $difunctional acids, butyrolactone, condensation products, catalyst residues etc!%! The +olatile substances mentioned abo+e can then be further reco+ered as mitures or indi+idual and sold as by5products or recycled back to the reactor to dri+e the runnin costs don! Most of these +olatile products that ere separated can enerate acetic acid on further oidation and treatment! The separation of ater and formic acid from the acetic acid product miture in+ol+es the use of se+eral distillation columns! Water remo+al is dicult and +ery costly hen compared to the rest of the purication process it is carried out by aEeotropic distillation ith entrainment aents such as ethers!
to the reactor to impro+e separation by formin a hih boilin aEeotrope ith formic acid eists that miht help dri+e the plant runnin and e*uipment costs don! The non5+olatile residue can usually be burned oJ to reco+er enery to heat other parts of the process! Traces of iodine that may remain in the product acetic acid produced may be remo+ed to increase the purity of the acid by fractional crystallisation or by addition of small amounts of methanol folloed by distillation of the methyl iodide that subse*uently forms! # small amount of propionic acid is also made and is typically found in the residue of the acetic acid nishin system and can be remo+ed from the residue by purin the column bottoms and can be a +iable product on its on!
# More detailed Ho sheet can be seen in the pae belo!
;
$othmer, "4)&, p! ;(%
(
Physical properties of all substances in+ol+ed .tandards
dimet methy ylethe l r acetat e
acetaldeh yde
butyraldeh yde
ethyl propinoi acetate c acid
Molecular
03!4(
;0!4(
00!41
;"!))
((!))
;0!4(
9olin point
5"0!(
13!2
"4!"
;0!(
;;!)
)0)!)1
KLC #uto5inition
&14
010
);1
"&4
"34
1)"
)"3!2
"&;
)((
"3&!21
"1;
&&0
KLC Meltin point
5)0)!1
52(
5)"&!&;
523!(3
5(&!3
5"4!1
KLC N/+ap $"2(O%
)2!&
&"!"2
"1!;3
&&!3
&1!;
1)
Kk8mol N/form $"2(O%
5)(0!)
50)4
5)33
5"&(!)
5000
51)4!(
Kk8mol =ensity
33(!&
2&0!"
;(0
(4)!3
(2;
2(;!2;
weight [g/mol]
temperature KLC Critical temperature
Physical properties of all substances in+ol+ed .tandards
dimet methy ylethe l r acetat e
acetaldeh yde
butyraldeh yde
ethyl propinoi acetate c acid
Molecular
03!4(
;0!4(
00!41
;"!))
((!))
;0!4(
9olin point
5"0!(
13!2
"4!"
;0!(
;;!)
)0)!)1
KLC #uto5inition
&14
010
);1
"&4
"34
1)"
)"3!2
"&;
)((
"3&!21
"1;
&&0
KLC Meltin point
5)0)!1
52(
5)"&!&;
523!(3
5(&!3
5"4!1
KLC N/+ap $"2(O%
)2!&
&"!"2
"1!;3
&&!3
&1!;
1)
Kk8mol N/form $"2(O%
5)(0!)
50)4
5)33
5"&(!)
5000
51)4!(
Kk8mol =ensity
33(!&
2&0!"
;(0
(4)!3
(2;
2(;!2;
31!1;
(3!4&
11!&"
)30!;
))&!30
)1"!(
weight [g/mol]
temperature KLC Critical temperature
$"4LC% Kk8m& /eat capacity K8molO
2
)eerences haynes, "4)0! CRC handbook of chemistry and physics othmer, O!, "444! Encyclopedia of chemical technology volume 1 (4th edition) Quincy, "4)4! National re protection association re protection guide to ha!ardous material"
Ullmanns, "44&! #llmanns Encyclopedia of $ndutrial Chemistry volume 1
)4