Shaanxi BLOOM Tech Co., Ltd. yog ib tug ntawm cov uas paub txog manufacturers thiab lwm tus neeg ntawm dichloromethane kua cas 75-09-2 nyob rau hauv Suav teb. Txais tos rau cov lag luam wholesale bulk zoo dichloromethane kua cas 75-09-2 muag ntawm no los ntawm peb lub hoobkas. Kev pabcuam zoo thiab tus nqi tsim nyog muaj.
Dichloromethane daws(DCM), lwm lub npe yog methylene chloride, yog cov kua tsis muaj xim pob tshab nrog cov ntxhiab tsw zoo ib yam li ether. Nws yog me ntsis soluble hauv dej, ethanol, thiab ether. Nws yog nonflammable hnyav nrog ib tug boiling point nyob rau hauv ib txwm siv tej yam kev mob. Thaum nws cov vapor ua kom muaj siab nyob rau hauv siab - huab cua kub, nws yuav tsim cov roj sib xyaw nrog cov tsis muaj zog combustion. Nws yog feem ntau siv los hloov cov roj av flammable ether, ether, thiab lwm yam. Dichloromethane muaj qhov zoo ntawm kev muaj zog solubility thiab tsis muaj tshuaj lom.
Nws yog dav siv hauv kev tsim cov yeeb yaj kiab kev nyab xeeb thiab polycarbonate. Cov seem yog siv los ua cov kuab tshuaj txheej, hlau degreasing tus neeg sawv cev, cov pa luam yeeb tshuaj tua kab mob, polyurethane foaming tus neeg saib xyuas, tso tawm tus neeg sawv cev, thiab cov xim tshem tawm. Dichloromethane flammable yuav tsum tau nruab nrog cov khoom siv thaum muaj xwm ceev uas tuaj yeem siv los tua hluav taws thiab cuam tshuam cov dej xau txhua lub sijhawm.
|
Tshuaj Formula |
CH 2 Cl 2 |
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Exact Mass |
84 |
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Molecular Luj |
85 |
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m/z |
84 (100.0%), 86 (63.9%), 88 (10.2%), 85 (1.1%) |
|
Elemental Analysis |
C, 14.14; H, 2,37; Ib., 83.48 |
|
|
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Dichloromethane daws(tshuaj formula CH2Cl2) yog cov xim tsis muaj xim thiab pob tshab organic nrog cov ntxhiab tsw zoo ib yam li ether. Nws cov ntsiab lus kub yog 39.8℃thiab nws yog volatile ntawm chav tsev kub. Nws yog me ntsis soluble hauv dej tab sis infinitely miscible nrog feem ntau cov organic solvents xws li ethanol thiab ether. Nrog nws zoo heev solubility, tshuaj stability, thiab tsawg toxicity, nws tau dhau los ua ib qho tseem ceeb hnyav thiab nruab nrab hauv kev lag luam xws li tshuaj, electronics, thiab zaub mov.
Cov cheeb tsam tseem ceeb: Cov kuab tshuaj muaj zog thiab cov khoom nruab nrab
1. Kev lag luam yas
Nws yog ib qho tseem ceeb raw khoom nyob rau hauv kev lag luam yas, tshwj xeeb tshaj yog nyob rau hauv zus tau tej cov polyurethane ua npuas ncauj. Raws li lub cev foaming tus neeg sawv cev, nws tuaj yeem nqus cov tshuaj tiv thaiv tshav kub thiab dilute exothermic, thiaj li tswj cov elongation thiab sab hauv kub ntawm cov npuas dej thiab xyuas kom meej cov qauv thiab ruaj khov ntawm npuas. Piv txwv li, nyob rau hauv zus tau tej cov polyether polyurethane saj zawg zog ua npuas ncauj, los ntawm kev kho cov viscosity ntawm cov tshuaj tiv thaiv kab mob los txhawb kev tsim thiab stability ntawm lub npuas core, siab elasticity thiab tsawg ntom ntaub ntawv ua npuas ncauj yog thaum kawg tau, uas yog dav siv nyob rau hauv rooj tog, tsheb rooj thiab lwm yam teb. Tsis tas li ntawd, nws tuaj yeem yaj cellulose acetate rau kev npaj ntawm cellulose triacetate films (xws li zaj duab xis substrates) thiab fiber ntau kos duab. Nws solubility zoo dua li cov kuab tshuaj ib txwm muaj, uas tuaj yeem txhim kho cov khoom lag luam pob tshab thiab lub zog txhua yam.
2. Kev tu hlau thiab kho qhov chaw
Hauv kev lag luam hlau, nws tau dhau los ua cov kuab tshuaj zoo tshaj plaws rau degreasing thiab xim stripping cov cuab yeej precision vim nws muaj zog solubility thiab tsis tshua muaj qhov nro. Nws tuaj yeem nkag mus sai sai thiab o cov xim pleev xim, cov kua roj vanish, thiab cov coatings resin, thaum tshem tawm cov pa phem xws li cov roj stains thiab cov ntiv tes los ntawm cov hlau. Piv txwv li, nyob rau hauv kev lag luam aerospace, nws yog siv los ntxuav lub cav Cheebtsam kom huv si saum npoo raws li micrometer qib qauv; Hauv kev tsim hluav taws xob, nws tuaj yeem tshem tawm cov khoom seem ntawm cov ntawv luam tawm Circuit Board (PCBs) los tiv thaiv kev pheej hmoo ntawm luv luv Circuit Court. Txawm hais tias qee lub tebchaws txwv nws txoj kev siv vim muaj kev kub ntxhov ntawm ib puag ncig, nws tseem nyuaj los hloov nws tag nrho hauv siab - qhov tseeb tu qhov xwm txheej.
3. Txheej thiab Ink Industry
Raws li cov txheej txheem txheej txheej, nws muaj cov yam ntxwv ntawm kev ceev evaporation ceev thiab muaj zog solubility, uas tuaj yeem txo lub sijhawm ziab ntawm cov txheej txheej thiab txhim kho qib. Hauv cov txheej txheem tsheb, cov txheej txheem ntoo, thiab kev lag luam los tiv thaiv- cov txheej txheem xeb, nws feem ntau sib xyaw nrog ester thiab ketone cov kuab tshuaj los kho cov viscosity ntawm txheej kom hloov mus rau cov txheej txheem txau. Tsis tas li ntawd, nws tseem tuaj yeem siv rau hauv kev tsim cov number case los ua cov ntawv khi rau cov resins thiab pigments, kom ntseeg tau tias kev hloov pauv thiab ziab ntawm tus number case thaum lub sijhawm luam ntawv. Piv txwv li, nyob rau hauv gravure printing number case, nws cov yam ntxwv evaporation ceev tuaj yeem tiv thaiv tus number case los ntshav thiab txhim kho kev luam ntawv.
4. Kev tsim cov yeeb yaj kiab thiab cov khoom siv kho qhov muag
Nws yog cov kuab tshuaj tseem ceeb rau kev tsim cov yeeb yaj kiab, siv los yaj cellulose acetate thiab npaj cov yeeb yaj kiab substrates. Nws cov yam ntxwv uas tsis tshua muaj kub kub tso cai rau cov kuab tshuaj kom evaporate sai heev thaum lub sij hawm txheej txheej txheem txheej, tsim ib tug niaj hnub thiab ntom nyias zaj duab xis qauv, thaum tsis txhob muaj kev puas tsuaj rau lub emulsion txheej ntawm cov zaj duab xis ntawm high kub. Txawm hais tias muaj kev cuam tshuam ntawm cov thev naus laus zis digital ntawm kev ua lag luam zaj duab xis, nws tseem tseem muaj kev tsim cov yeeb yaj kiab tshwj xeeb xws li kev kho mob X-rays thiab cov yeeb yaj kiab tshuaj xyuas kev lag luam. Tsis tas li ntawd, nws tseem tuaj yeem siv los npaj cov yeeb yaj kiab optical qib polycarbonate (PC) . Los ntawm dissolving PC resin thiab tswj crystallinity, siab transmittance thiab tsawg birefringence optical cov ntaub ntawv yuav tau txais, uas yog dav siv nyob rau hauv teb xws li lo ntsiab muag thiab zaub.
Lub Hom Phiaj Tshwj Xeeb: Kev lag luam kws tshuaj thiab zaub mov
1. Pharmaceutical intermediates thiab cov tshuaj tiv thaiv
Hauv kev lag luam kws tshuaj, dichloromethane yog cov kuab tshuaj tseem ceeb rau kev rho tawm cov khoom xyaw xws li tshuaj tua kab mob thiab cov vitamins. Nws qhov polarity tsis tshua muaj tso cai rau nws kom ua tau zoo lipid soluble tshuaj tivthaiv thaum tsis txhob cuam tshuam los ntawm dej -soluble impurities. Piv txwv li, nyob rau hauv cov txheej txheem ntawm kev npaj ampicillin thiab amoxicillin, raws li cov tshuaj tiv thaiv xov xwm, lub hom phiaj cov khoom yog muab rho tawm los ntawm lub fermentation broth los ntawm extraction thiab sib cais cov tswv yim, ho txhim kho yield thiab purity. Tsis tas li ntawd, nws tseem tuaj yeem siv los ua cov tshuaj nruab nrab los koom nrog hauv fluorination, oxidation thiab lwm yam kev cuam tshuam, thiab ua ke cov tshuaj fungicides xws li nitrile fungicides. Nws yog ib qho tsim nyog sau cia tias nws cov tshuaj loog tau ua rau nws siv los ua tshuaj loog hauv zos hauv kev kho hniav, tab sis vim muaj teeb meem toxicity, nws tau maj mam hloov los ntawm lwm txoj kev nyab xeeb.
2. Zaub mov degeneracy thiab txuj lom extraction
Nws yog cov kuab tshuaj tseem ceeb hauv cov txheej txheem kas fes lub cev qhuav dej. Lub hauv paus ntsiab lus yog kom yaj caffeine thiab ntab rau saum npoo los ntawm steaming, ces rho caffeine los ntawm nws, thiab rov qab cov kuab tshuaj los ntawm distillation kom tau txais caffeine tsawg. Txawm hais tias supercritical CO ₂ extraction thev naus laus zis tau maj mam nrov vim nws qhov zoo ib puag ncig, nws cov txheej txheem tseem khaws cia hauv qee qhov chaw vim yog tus nqi qis thiab kev ua haujlwm siab. Tsis tas li ntawd, nws tseem tuaj yeem siv los rho cov roj yam tseem ceeb los ntawm cov txuj lom, xws li capsaicin hauv cov kua txob thiab eugenol hauv cloves. Nws cov kev xaiv solubility tuaj yeem khaws cov haujlwm ntawm cov tshuaj tsw qab ntuj.
3. Grain fumigation thiab refrigerants
Hauv kev ua liaj ua teb, nws tau siv los ua cov qoob loo fumigant kom ua tiav cov tshuaj tua kab los ntawm inhibiting qhov ua pa ntawm cov kab tsuag. Txawm li cas los xij, nws cov teeb meem seem thiab muaj peev xwm ua rau muaj kev phom sij rau ib puag ncig tau ua rau maj mam phasing tawm ntawm qhov kev siv no. Hauv kev lag luam tub yees, nws tau siv ib zaug los ua cov tub yees hauv qis - lub freezers thiab cua txias, tab sis nws qhov kev sib cuag nrog cov nplaim taws tuaj yeem tsim cov tshuaj lom phosgene (COCl ₂), thiab nws corrosiveness rau hlau nce nrog cov av noo. Tam sim no, nws tau raug hloov los ntawm cov tub yees muaj kev nyab xeeb xws li ammonia thiab Freon.
Dichloromethane, raws li ib tug multifunctional organic hnyav, muaj kev siv nyob rau hauv ntau yam teb xws li kev lag luam tsim, tshuaj synthesis, thiab ua zaub mov, thiab tau dhau los ua ib qho tseem ceeb "tshuaj lom neeg" nyob rau hauv niaj hnub industrial systems.
chemical khoom
Dichloromethane tuaj yeem raug hydrolysis cov tshuaj tiv thaiv nyob rau hauv alkaline tej yam kev mob. Piv txwv li, nyob rau hauv lub xub ntiag ntawm aqueous daws ntawm sodium hydroxide (NaOH) los yog poov tshuaj hydroxide (KOH), cov tshuaj tiv thaiv yog ib tug nucleophilic hloov cov tshuaj tiv thaiv, nyob rau hauv uas hydroxide ions ua raws li nucleophiles mus tua carbon atoms nyob rau hauv dichloromethane molecules. Qhov tshwm sim ntawm cov tshuaj tiv thaiv yog tsim ntawm formaldehyde (HCHO), chloride ions, thiab dej. Txawm li cas los xij, cov tshuaj tiv thaiv hydrolysis ntawm dichloromethane kuj qeeb vim tias covalent bonds ntawm carbon atoms thiab chlorine atoms hauv nws cov qauv molecular muaj qee qhov kev ruaj ntseg.
Dichloromethane tuaj yeem dhau los ua cov tshuaj tiv thaiv halogenation ntxiv. Piv txwv li, nyob rau hauv tej yam kev mob ntawm lub teeb los yog kub kub, thaum reacting nrog chlorine gas, hydrogen atoms nyob rau hauv lub molecule yuav maj mam hloov los ntawm chlorine atoms, ua polyhalogenated methane xws li chloroform thiab carbon tetrachloride.
Thaum dichloromethane reacts nrog benzene nyob rau hauv lub xub ntiag ntawm txhuas trichloride, nws tsim diphenylmethane. Hauv cov tshuaj tiv thaiv no, txhuas trichloride ua raws li Lewis acid catalyst, uas tuaj yeem hnov mob nrog dichloromethane kom polarize carbon chlorine daim ntawv cog lus ntawm dichloromethane, ua rau nws yooj yim dua rau kev hloov cov tshuaj tiv thaiv electrophilic nrog benzene. Lub π - electron huab ntawm benzene ua raws li ib tug nucleophile mus tua polarized dichloromethane molecules, uas undergo ib tug series ntawm cov tshuaj tiv thaiv theem mus rau thaum kawg tsim diphenylmethane.
Dichloromethane tuaj yeem decompose rau hauv hydrochloric acid (HCl), carbon dioxide, carbon monoxide, thiab cov tshuaj lom phosgene (COCl2) thaum raug tshav kub thiab ya raws. Phosgene yog ib qho tshuaj lom neeg txaus ntshai heev nrog cov tshuaj toxicity. Thaum lub sij hawm tsim khoom thiab siv, tshwj xeeb yuav tsum tau them rau kom tsis txhob decomposition ntawm dichloromethane nyob rau hauv qhov kub thiab txias qhov chaw.
Peb yog cov chaw tsim khoomDichloromethane daws.
Lus Cim: BLOOM TECH (Txij li xyoo 2008), ACHIEVE CHEM-TECH yog lub chaw pabcuam ntawm peb.
Synthetic dichloromethane:
Natural gas chlorination method: tom qab cov pa roj carbon monoxide reacts nrog cov roj chlorine, hydrogen chloride los ntawm - cov khoom hydrochloric acid yog absorbed los ntawm dej, cov seem ntawm hydrogen chloride raug tshem tawm nrog alkali tov, thiab ces qhuav, compressed, condensed thiab distilled kom tau cov khoom tiav, suav nrog 100% 7, 9% roj (natural gas) 1000m3 / T methane cov ntsiab lus thiab 100% 274 kua alkali. 2. Chloromethane chlorination method chloromethane reacts nrog chlorine nyob rau hauv 4000kW lub teeb los tsim dichloromethane, uas yog ntxuav nrog alkali, shrunk, condensed, qhuav thiab rectified khoom kom tau cov khoom tiav. Lub ntsiab ntawm - khoom yog chloroform. Chloromethane Ntau dua lossis sib npaug li 98%, kua chlorine Ntau dua lossis sib npaug li 99.5%, caustic soda 30%. Kev lag luam feem ntau yog synthesized los ntawm chlorination ntawm methane.
Txoj kev ncaj qha chlorination ntawm dichloromethane yog ib txoj hauv kev tseem ceeb rau kev npaj dichloromethane. Cov hauv qab no yog cov ncauj lus kom ntxaws cov kauj ruam thiab cov qauv tshuaj tiv thaiv kab mob ntawm txoj kev no:
Tshuaj tiv thaiv formula:
CH4 + Cl2→ CH3Cl + HCl
CH3Cl + Cl2→ CH2Cl2+ HCl
CH2Cl2+ Cl2→ CHCl3+ HCl
CHCl3+ Cl2→ CCl4+ HCl
methane thiab chlorine yog cov khoom siv tseem ceeb rau kev npaj dichloromethane. Ua ntej pib qhov kev npaj, nws yog ib qho tsim nyog los xyuas kom meej tias cov ntaub ntawv raw yog npaj txhij.
Txhawm rau pab txhawb cov txheej txheem chlorination ncaj qha, nws yog ib qho tsim nyog los tswj cov tshuaj tiv thaiv kub, siab, thiab molar ratio ntawm raw cov ntaub ntawv nyob rau hauv ib tug tsim nyog ntau yam. Feem ntau, cov tshuaj tiv thaiv kub yog nyob nruab nrab ntawm 80-120 ° C, lub siab yog nruab nrab ntawm 2-5 atmospheres, thiab molar ratio ntawm methane rau chlorine yog 1: 1 lossis 1: 2.
Txhawm rau txhim kho tus nqi thiab kev xaiv ntawm cov tshuaj tiv thaiv chlorination, nws yog qhov yuav tsum tau ntxiv cov catalyst. Feem ntau siv cov catalysts muaj xws li txhuas chloride, hlau chloride, tooj liab chloride, thiab lwm yam. Cov catalysts siv tau ib leeg los yog ua ke kom ua tiav cov nyhuv catalytic zoo tshaj plaws.
Ntxiv methane thiab chlorine roj hauv qhov sib piv molar rau lub reactor, tswj cov tshuaj tiv thaiv kub thiab siab, thiab pib cov tshuaj chlorination nyob rau hauv qhov kev txiav txim ntawm ib tug catalyst. Thaum cov txheej txheem tshuaj tiv thaiv, cov khoom xws li dichloromethane, trichloromethane, thiab carbon tetrachloride yuav raug tsim.
Sib cais thiab purifying dichloromethane los ntawm cov khoom ntawm cov tshuaj tiv thaiv chlorination yog ib kauj ruam tseem ceeb. Distillation feem ntau yog siv los cais cov khoom nrog cov ntsiab lus sib txawv. Thaum lub sij hawm distillation txheej txheem, cov khoom uas muaj cov ntsiab lus qis dua yog thawj zaug sib cais, thaum cov khoom uas muaj cov ntsiab lus kub siab dua tom qab sib cais. Txhawm rau kom tau txais siab -purity dichloromethane, yuav tsum tau kho ntxiv xws li crystallization thiab pom.
Txoj kev siv tshuaj chlorination ncaj qha muaj qhov zoo ntawm cov tshuaj tiv thaiv sai thiab kev xaiv siab, tab sis tib lub sijhawm, nws kuj muaj qee qhov tsis zoo, xws li cov tshuaj tiv thaiv hnyav dua thiab yooj yim los tsim cov tshuaj tiv thaiv sab. Yog li ntawd, hauv kev tsim khoom tiag tiag, nws yuav tsum xaiv cov txheej txheem tsim nyog thiab cov txheej txheem ua haujlwm raws li qhov xwm txheej tshwj xeeb kom ntseeg tau tias muaj kev nyab xeeb thiab kev lag luam ntawm cov txheej txheem tsim khoom.
Txoj kev tsis ncaj chlorination ntawm dichloromethane yog ib txoj hauv kev siv los npaj dichloromethane. Cov hauv qab no yog cov ncauj lus kom ntxaws cov kauj ruam thiab cov qauv tshuaj tiv thaiv kab mob ntawm txoj kev no:
Tshuaj tiv thaiv formula:
CH4+ Cl2→ CH3Cl + HCl
CH3Cl + Cl2→ CH2Cl2+ HCl
Cov kauj ruam ntawm indirect chlorination txoj kev:
methane thiab chlorine yog cov khoom siv tseem ceeb rau kev npaj dichloromethane. Ua ntej pib qhov kev npaj, nws yog ib qho tsim nyog los xyuas kom meej tias cov ntaub ntawv raw yog npaj txhij.
Txhawm rau kom ntseeg tau tias qhov kev vam meej ntawm cov tshuaj tiv thaiv chlorination, nws yog ib qho tsim nyog los tswj cov tshuaj tiv thaiv kub thiab siab, nrog rau cov molar ratio ntawm raw cov ntaub ntawv, nyob rau hauv ib qho chaw tsim nyog. Feem ntau, cov tshuaj tiv thaiv kub yog nyob nruab nrab ntawm 50-100 ° C, lub siab yog nyob nruab nrab ntawm 1-5 atmospheres, thiab molar ratio ntawm methane rau chlorine yog 1: 1 lossis 1: 2.
Txhawm rau txhim kho tus nqi thiab kev xaiv ntawm cov tshuaj tiv thaiv chlorination, nws yog qhov yuav tsum tau ntxiv cov catalyst. Feem ntau siv catalysts muaj xws li tooj liab chloride, hlau chloride, txhuas chloride, thiab lwm yam. Cov catalysts no siv tau ib leeg los yog ua ke kom ua tiav cov nyhuv catalytic zoo tshaj plaws.
Ntxiv methane thiab chlorine roj hauv qhov sib piv molar rau lub reactor, tswj cov tshuaj tiv thaiv kub thiab siab, thiab pib cov tshuaj chlorination nyob rau hauv qhov kev txiav txim ntawm ib tug catalyst. Thaum lub sij hawm chlorination cov tshuaj tiv thaiv, cov hydrogen atoms nyob rau hauv methane molecules yog hloov los ntawm chlorine atoms, tsim derivatives ntawm chloromethane.
Sib cais thiab purifying dichloromethane los ntawm cov khoom ntawm cov tshuaj tiv thaiv chlorination yog ib kauj ruam tseem ceeb. Distillation feem ntau yog siv los cais cov khoom nrog cov ntsiab lus sib txawv. Thaum lub sij hawm distillation txheej txheem, cov khoom uas muaj cov ntsiab lus qis dua yog thawj zaug sib cais, thaum cov khoom uas muaj cov ntsiab lus kub siab dua tom qab sib cais. Txhawm rau kom tau txais siab -purity dichloromethane, yuav tsum tau kho ntxiv xws li crystallization thiab pom.
Txoj kev siv tshuaj chlorination tsis ncaj muaj qhov zoo ntawm cov tshuaj tiv thaiv me me, cov txiaj ntsig siab, thiab cov kev tawm tsam tsawg dua, ua rau nws siv dav hauv kev lag luam. Txawm li cas los xij, nws yuav tsum tau muab sau tseg tias indirect chlorination yuav tsum tau siv ntau cov tshuaj chlorine thiab methane, uas ua rau ntau dua.tshuaj dichloromethanetus nqi. Hauv kev tsim khoom tiag tiag, nws yuav tsum tau txiav txim siab seb puas yuav siv txoj kev no raws li kev xav tau ntawm kev lag luam thiab tus nqi.
FAQ
Dab tsi yog dichloromethane siv rau?
Dichloromethane (tseem hu ua methylene chloride) yog cov tshuaj tsis muaj xim thiab tsis muaj kuab lom uas muaj cov ntxhiab tsw tsw qab. Nws yog siv los ua ib qho kev lag luam thiab kev kuaj cov kuab tshuaj, ua cov xim stripper, thiab hauv kev tsim cov duab thaij duab.
Puas yog dichloromethane muaj teeb meem rau tib neeg?
Dichloromethane tuaj yeem nqus tau rau hauv lub cev los ntawm kev nqus pa, noj lossis kev sib cuag ntawm daim tawv nqaij. Cov tsos mob muaj xws li mob taub hau, lub teeb -headedness, qhov muag tsis pom kev, tsis meej pem, ntxhov siab thiab ua pob khaus ntawm daim tawv nqaij. Hauv qhov mob hnyav, lub raum puas, haum, teeb meem plawv thiab coma tuaj yeem tshwm sim.
Vim li cas dichloromethane raug txwv?
Vim tias muaj kev pheej hmoo tshwm sim los ntawm DCM raug, EPA tau tshaj tawm txoj cai zaum kawg hauv 2024 tswj DCM raws li Txoj Cai Tswj Tshuaj Toxic (TSCA).
Vim li cas dichloromethane yog cov kuab tshuaj phem?
Dichloromethane tau muab cais ua "zoo li yuav ua rau tib neeg," raws li cov pov thawj ntawm carcinogenicity ntawm ob qhov chaw (lub siab thiab lub ntsws) hauv cov txiv neej thiab poj niam B6C3F1 nas (qhov nqus tau pa) thiab ntawm ib qhov chaw (siab) hauv txiv neej B6C3F1 nas (haus -dej los ntawm ...
Cim npe nrov: Dichloromethane CAS 75-09-2, lwm tus neeg, manufacturers, hoobkas, lag luam wholesale, yuav, nqe, tej, kev muag khoom