Terephthalic Acid (PTA)tau pom nyob rau hauv lub xyoo pua 19th. Nws tsis yog txog thaum xyoo 1949 thaum Tebchaws Askiv lub tuam txhab tshuaj lom neeg kev lag luam pom tias PTA (los yog nws cov khoom siv los ntawm dimethyl terephthalate) yog cov khoom siv tseem ceeb rau cov khoom siv polyester uas nws tau pib ua dav dav. Xyoo 1981, lub ntiaj teb PTA cov zis tau mus txog 3.485mt. Thawj txoj kev tsim khoom lag luam yog nitric acid oxidation. Nrog rau kev txhim kho ntawm kev lag luam polyester, ib txoj hauv kev tsim PTA los ntawm ntau yam khoom siv raw thiab los ntawm ntau txoj kev tau tsim (Daim duab 1). Txoj kev pheej yig tshaj plaws thiab siv dav yog txoj kev kub-kub ua kua-theem oxidation siv p-xylene li raw khoom (saib daim duab xim), uas muaj cov txiaj ntsig siab thiab cov txheej txheem luv luv. Qhov kub-kub oxidation ntawm p-xylene muaj cov tshuaj tiv thaiv me me thiab corrosion me ntsis, tab sis cov txheej txheem yog ntev thiab tsuas yog siv nyob rau hauv ob peb lub hoobkas. Nws kuj tau pom zoo tias p-xylene yog thawj zaug ammoniated thiab oxidized los tsim p-phenylenenitrile, thiab tom qab ntawd hydrolyzed los tsim PTA. Txawm li cas los xij, txoj kev no tsis tau raug tsim los ntawm qhov loj. Vim yog tus nqi siab ntawm kev sib cais p-xylene los ntawm kev sib xyaw xylene, qee txoj kev pib los ntawm lwm cov khoom siv raw kuj tau tsim. Txawm hais tias qee qhov ntawm cov txheej txheem no tau ua haujlwm ntev ntev, lawv tsis tau tsim, thaum lwm tus tsuas yog nyob rau theem kev sim nruab nrab.
Kev kub siab ua kua theem oxidation ntawm p-xylene:
Txoj cai lij choj no tau tsim thawj zaug los ntawm Asmeskas cov tuam txhab medieval thiab British bnemen chemical kev lag luam tuam txhab nyob rau hauv 1955, thiab tau industrialized los ntawm American Amoco chemical tuam txhab nyob rau hauv 1958. Tag nrho cov tshuaj tiv thaiv mis yog (Fig. 1):
Txawm li cas los xij, cov txheej txheem tiag tiag yog qhov nyuaj dua. Qee tus neeg xav tias nws yog los ntawm cov kauj ruam hauv qab no (Daim duab 2):
txij li ob pawg methyl tsis yooj yim rau oxidized, cov txheej txheem tshuaj tiv thaiv yog ib qho yooj yim kom nres ntawm theem ntawm p-methylbenzoic acid los yog p-carboxybenzaldehyde. Txhawm rau txuas ntxiv cov tshuaj tiv thaiv oxidation, Amoco chemical tuam txhab txais cov txheej txheem kub thiab ntxiv cocatalyst bromide (feem ntau tetrabromoethane) rau cobalt acetate manganese acetate catalyst.
Bromine tsim los ntawm bromide tuaj yeem ua rau cov saw oxidation cov tshuaj tiv thaiv uas tsim cov dawb radicals. Cov tshuaj tiv thaiv oxidation feem ntau yog ua nyob rau hauv ntauwd reactor. Cov tshuaj tiv thaiv kub yog {{0}} degree, tab sis feem ntau ntawm lawv yog siab tshaj 200 degree . Kev kub siab tuaj yeem ua kom cov tshuaj tiv thaiv thiab txo cov khoom nruab nrab, tab sis cov khoom lag luam los ntawm decomposition kuj nce. Txij li thaum tshav kub ntawm cov tshuaj tiv thaiv raug tshem tawm los ntawm cov dej thiab cov kuab tshuaj acetic acid uas ua los ntawm cov evaporation cov tshuaj tiv thaiv, cov tshuaj tiv thaiv siab muaj feem xyuam rau tus nqi evaporation, feem ntau 1.5-3.0mpa. Lub sij hawm nyob yog 0.5 ~ 3H. Qhov nce ntawm cov concentration ntawm cobalt acetate thiab manganese acetate tuaj yeem ua rau lub sijhawm nyob hauv lub sijhawm luv lossis txo qhov ntsuas kub. Cov txiaj ntsig ntawm p-xylene hauv cov txheej txheem kub oxidation tuaj yeem ncav cuag ntau dua 90 feem pua. Vim muaj qhov kub thiab txias thiab muaj cov bromine, uas muaj cov nyhuv corrosion, lub reactor xav tau titanium lossis titanium hauv ob sab phlu khoom.
PTA muaj me ntsis solubility hauv acetic acid, thiab cov khoom oxidation yog nyob rau hauv daim ntawv ntawm slurry. Tom qab centrifugation thiab ziab, khoom crude PTA tau txais. Qhov phem tshaj impurity yog p-carboxybenzaldehyde (cov ntsiab lus: 1000-5000ppm). Crude PTA tuaj yeem siv los tsim polyester los ntawm dimethyl terephthalate, tab sis ib txoj hauv kev zoo dua yog purification, siv cov PTA refined ua raw khoom ntawm polyester ncaj qha. Txoj kev siv cov refining feem ntau yog txoj kev hydrogenation tau txais los ntawm Amoco, uas yog, cov PTA nyoos yaj hauv dej nyob rau hauv qhov kub thiab txias, ces cov impurities yog hydrogenated nyob rau hauv lub xub ntiag ntawm palladium catalyst, thiab ces crystallized thiab lim kom tau fiber ntau qib. (purity specification haum rau spinning). Cov ntsiab lus ntawm p-carboxybenzaldehyde hauv cov khoom tuaj yeem tsawg dua 25ppm. Cov txiaj ntsig ntawm terephthalic acid nyob rau hauv cov txheej txheem refining yog ntau tshaj 97 feem pua. Ntxiv nrog rau hydrogenation, cov txheej txheem refining muaj xws li sublimation.
Tsawg kub oxidation ntawm p-xylene cov tshuaj tiv thaiv kub ntawm txoj kev no feem ntau qis dua 150 degree. Txawm hais tias cobalt acetate kuj tseem siv los ua catalyst, bromide tsis siv. Lub sijhawm no, txhawm rau hloov cov methyl pawg thib ob rau hauv pawg carboxyl, feem ntau yuav tsum tau ntxiv cov Co oxide uas nquag tsim cov tshuaj peroxide thaum lub sijhawm oxidation. Piv txwv li, American Mobil Chemical Company siv methyl ethyl ketone, lub tuam txhab American Eastman Kodak siv acetaldehyde, thiab lub tuam txhab Japanese Toray siv trimethyl acetaldehyde. Cov tshuaj no kuj tsim acetic acid tom qab oxidation, thiab acetic acid yog cov hnyav siv rau oxidation. Cov kev mob tshwm sim yog raws li nram no: qhov kub yog 120 ~ 150 degree, lub siab yog 3Mpa, thiab tawm los yog 96 feem pua. Cov txheej txheem oxidation qis qis tsis muaj bromide thiab cov tshuaj tiv thaiv qis, yog li lub reactor tsis tuaj yeem siv cov khoom siv titanium.
Phthalic anhydride hloov txoj kev:
Lub tuam txhab patent ntawm Henkel (txheej txheem 11, 12, 13 thiab 16 hauv daim duab 4) kuj hu ua Henkel I method. Industrialization tau pom los ntawm Japanese Teijin tuam txhab. Hauv txoj kev no, phthalic anhydride yog thawj zaug hloov mus rau hauv dipotassium phthalate, dipotassium terephthalate tuaj yeem tau los ntawm kev hloov pauv cov tshuaj tiv thaiv, thiab tom qab ntawd PTA tuaj yeem tau los ntawm acidification (los yog kua qaub nag). Hauv cov kauj ruam no, qhov nyuaj tshaj plaws yog kev hloov pauv cov tshuaj tiv thaiv. Cadmium lossis zinc catalyst yog siv rau hauv cov tshuaj tiv thaiv no. Cov tshuaj tiv thaiv kub yog 350-450 degree, lub siab yog 1-5mpa, thiab cov qauv reactor kuj nyuaj heev. Nws yog qhov nyuaj heev los hloov cov poov tshuaj sulfate tsim tom qab acidification nrog sulfuric acid rau hauv potassium hydroxide rau kev rov ua dua tshiab, yog li nws tsuas yog siv tau los ua cov tshuaj poov tshuaj. Henkel I txheej txheem yog kim nyob rau hauv raw cov ntaub ntawv thiab complex technology. Yog li ntawd, txawm hais tias nws tau raug industrialized, nws tsis tau nrov.
Toluene oxidation disproportionation txoj kev:
Kuj hu ua Henkel II txoj kev (piv txwv li 1, 12, 14 thiab 16 txheej txheem hauv daim duab 4). Ntawd yog, toluene yog siv los ua raw khoom, thiab benzoic acid yog npaj los ntawm oxidation ua ntej, thiab nws cov poov tshuaj ntsev yog disproportioned los tsim benzene thiab dipotassium terephthalate, uas yog acidified los ua PTA. Qhov tseem ceeb tshaj plaws yog cov tshuaj tiv thaiv tsis sib xws, uas yog ua tiav ntawm 400 degree, 2MPa thiab muaj cov pa roj carbon dioxide. Txoj cai lij choj no tau tsim nyob rau hauv Nyij Pooj los ntawm Mitsubishi Chemical Industry Corporation hauv xyoo 1963. Nws raug txiav tawm xyoo 1975 vim yog tus nqi siab. Txawm li cas los xij, txij li cov khoom siv raw toluene pheej yig dua li p-xylene, qee lub tuam txhab hauv qee lub tebchaws tseem tab tom kawm thiab txhim kho txoj kev no.