Puas yog PTFE muaj kev nyab xeeb rau cua sov Organic Solvents Zoo li Acetone lossis Toluene?

Acetone yog heev volatile thiab flammable, ib yam nkaus thiab. Toluene yuav o qee cov polymers. Cov kuab tshuaj no yuav tsum tau ua kom sov yam tsis muaj tshuaj tiv thaiv, nqus los yog softening ntawm cov khoom siv cua sov. PTFE feem ntau suav hais tias yog tshuaj tsis muaj zog, tab sis ua li cas nrog cov kuab tshuaj organic? Puas muaj kev nyab xeeb siv lossis puas muaj kev phom sij zais?

PTFE yog siv nyob rau hauv hnyav- tuav daim ntaub ntawv vim nws tsis coj zoo li feem ntau cov polymers nyob rau hauv kev sib cuag nrog cov organic solvents. Qhov saum npoo yog tsim los ntawm nws qhov hnyav molecular hnyav heev thiab cov qauv zoo sib xws ntawm cov pob txha ntawm cov pob txha uas tau thaiv los ntawm fluorine atoms, tiv thaiv yuav luag txhua cov kuab tshuaj. Acetone, toluene, isopropyl cawv (IPA), ethanol, methanol, dichloromethane, tetrahydrofuran (THF), ethyl acetate, hexane, thiab xylene tag nrho cuam tshuam nrog PTFE negligibly. Hauv cov khoom nruab nrab no PTFE tsis pom qhov o, yaj lossis muag muag txawm tias thaum tshav kub mus rau nws txoj kev txwv tsis zoo li polypropylene, polyethylene lossis qee qhov tsawg dua crystallinity fluoropolymers (xws li qee qib ntawm FEP lossis PFA ntawm qhov kub siab). Kev nkag mus ntawm cov molecules los ntawm cov polymer matrix yog xyaum nil ntawm qhov ntsuas kub hauv qab 200 degree. Qhov no tsis yog -cov cuab yeej sib tham sib yog ib qho ntawm qhov zoo tshaj plaws ntawm PTFE, uas ua rau encapsulated PTFE cua sov daim hlau zoo heev rau kev sib cuag ncaj qha los yog tsis ncaj nraim nrog cov kuab tshuaj da dej hauv reflux, distillation, extractions lossis ziab ua haujlwm.

Qhov teeb meem kev nyab xeeb tseem ceeb nrog cua sov cov kuab tshuaj organic tsis yog hais txog kev sib raug zoo ntawm cov ntaub ntawv, tab sis qhov xwm ntawm cov kua lawv tus kheej: flammability, tsawg flash ntsiab lus thiab vapor siab. Acetone muaj qhov taw tes ntawm -20℃thiab kub kub ntawm 56 degree. Toluene muaj qhov taw tes ntawm 4℃thiab qhov kub ntawm 111 degree. IPA muaj qhov flash point ntawm 12 degree. Thaum cov vapors raug tsim, qhov kev pheej hmoo hloov pauv los ntawm cov tshuaj tiv thaiv ntawm cov kuab tshuaj thiab lub rhaub kom igniting qhov chaw xws li sparks, kub qhov chaw saum autoignition kub, los yog static paug. Lub inertness ntawm PTFE txhais tau hais tias lub phaj nws tus kheej yuav tsis yog lub hauv paus ntawm catalytic tawg, leaching los yog nto ignition. Tsis tas li ntawd, nws tsis yog - ntxeem tau, tsis tshua muaj zog saum npoo av txhais tau hais tias cov kuab tshuaj spilled zoo li hlaws thiab dov tawm tau yooj yim, txwv tsis pub muaj cov kua dej sib txuas nrog cov khoom siv hluav taws xob lossis tsim cov chaw ntub dej tsis tu ncua. Ntau lwm cov ntaub ntawv, ntawm qhov tod tes, tsim teeb meem. Cov cua sov hlau (stainless steel, titanium) tuaj yeem tiv taus cov kuab tshuaj ntshiab tab sis corrode sai heev thaum muaj cov kab dej, cov kua qaub los yog chlorides, tso cov hlau ions uas tuaj yeem ua rau cov kab mob hauv qab. Polypropylene lossis HDPE cov tais thiab cov tshuab tso cua sov feem ntau o los yog sib cais hauv cov tshuaj tsw qab lossis cov tshuaj chlorinated uas ua rau cov dej xau lossis cov tshuab ua haujlwm tsis zoo. PTFE yog dawb los ntawm tag nrho cov teeb meem no.

Kev ua haujlwm nyab xeeb yog hais txog kev tswj cov txheej txheem txaus ntshai thiab tsis yog hais txog cov khoom siv ntawm lub tshuab cua sov. Kub yuav tsum tau tswj kom raug. Siv PID maub los nrog kev ywj pheej overtemperature txwv hloov teeb tsa 10-20℃saum toj qhov xav tau tab sis nyob deb ntawm qhov hnyav ntawm qhov kub thiab txias (~ 465℃rau acetone, ~ 480℃rau toluene). Qhov kev tawm tswv yim zoo tshaj plaws yog los ntawm lub thermocouple lossis Pt100 sojntsuam rau hauv cov kua, uas yuav tsis txhob khiav tawm cua sov yog tias cov kuab tshuaj poob qis lossis yog tias nws yuav tsum pib npau taws sai. Rau cov thawv qhib, muaj zog tso pa tawm hauv zos, nyiam dua lub fume hood lossis downdraft table, yuav ua kom cov pa ntau dua li qhov qis dua. Hauv kaw lossis ib nrab- kaw cov tshuab, xav txog cov pa roj tsis zoo (nitrogen tshem tawm) kom tshem tawm cov pa oxygen thiab txo qis cov nplaim taws. Cov khoom siv hluav taws xob thiab kev sib txuas yuav tsum raug ntsuas rau ib puag ncig: tawg- pov thawj (Class I, Div 1 lossis Cheeb Tsam 1) yog tias cov vapors yuav tsum sib sau ua ke, lossis tsawg kawg kaw thiab corrosion- tiv taus qee zaus qee zaum tawg. Kev tshuaj xyuas tsis tu ncua pom tau tias tsis muaj cov kuab tshuaj tau ua phem rau hauv cov thawv sib txuas lossis cov kev coj ua - txawm hais tias qhov no tsis zoo li yog vim tsis yog -tus cwj pwm ntub dej ntawm PTFE.

Kev ua tau zoo ntawm cov organic synthesis thiab pilot scale processing qhia tau hais tias tsim nyog ua PTFE cua sov daim hlau qhia tsis muaj degradation tom qab xyoo ntawm kev pab cuam nrog cov kuab tshuaj. Deg discoloration tuaj yeem tshwm sim vim muaj kev cuam tshuam ntev rau qee yam kab mob (xws li peroxides hauv ethers) tab sis tsis cuam tshuam rau kev ncaj ncees lossis kev ua haujlwm thermal. Thaum cua sov sib xyaw ntawm cov kuab tshuaj nrog cov tshuaj reactive additives (xws li cov ntxhia acids hauv cov tshuaj ntxuav, organometallics hauv Grignard setups), xyuas tag nrho compatibility; cov additive, tsis yog cov kuab tshuaj, tej zaum yuav muaj kev phom sij. Tab sis nyob rau hauv cov kev pab cuam ntshiab los yog raug organic solvent, PTFE tsis cuam tshuam.

PTFE cua sov daim hlau muab ib txoj kev nyab xeeb thiab vam khom rau cua sov cov kuab tshuaj organic. Kev ceev faj txog kev nyab xeeb rau cov kua hluav taws xob yuav tsum raug soj ntsuam. Lawv tshem tawm cov kev txhawj xeeb ntawm cov khoom, yog li cov kws tshuaj thiab cov kws tsim qauv tuaj yeem tsom ntau dua rau cov txheej txheem tsis ua haujlwm - qhov kub thiab txias reflux tus nqi, thiab kev tswj vapor, es tsis yog ntawm degradation ntawm cov cuab yeej. Qhov kev hloov pauv no ua rau lawv muaj txiaj ntsig zoo hauv kev tshawb fawb thiab kev tsim khoom qhov twg cov khoom siv hnyav ua haujlwm tsis tu ncua, los ntawm cov tsev kawm qib siab sim ua cov tshuaj distillation me me rau cov chaw tsim khoom lag luam uas ua tiav loj -batch extractions lossis recrystallizations.