Ib qho tseem ceeb tshaj plaws nitrogen tebchaw yog ammonia. Raws li nws lub cev muaj zog, nws yog cov roj uas tsis muaj xim nrog cov ntxhiab tsw ntxhiab tsw (qhov no yog qhov tsis hnov tsw ntawm cov tshuaj aqueous ntawm ammonium hydroxide NH₃·H₂O). Gas yog heev soluble nyob rau hauv dej. Hauv cov kua dej aqueous, ammonium yog lub hauv paus tsis muaj zog. Nws yog ib qho ntawm cov khoom tseem ceeb tshaj plaws ntawm kev lag luam tshuaj.
NH₃ yog qhov txo qis, zoo li hauv ammonium molecule, nitrogen muaj qis tshaj oxidation xeev -3. Ntau tus yam ntxwv ntawm ammonia yog txiav txim siab los ntawm ib khub ntawm ib qho hluav taws xob hauv nitrogen atom - ntxiv cov tshuaj tiv thaiv nrog ammonia tshwm sim vim nws muaj (cov khub ntawm singles nyob rau ntawm qhov chaw dawb ntawm Proton H⁺).
Yuav ua li cas kom tau ammonia
Muaj ob txoj hauv kev tseem ceeb rau kev tau txais ammonia: ib qho hauv chav kuaj, lwm qhov hauv kev lag luam.
Xav txog kev tsim cov ammonia hauv kev lag luam. Kev sib piv ntawm molecular nitrogen thiab hydrogen: N₂ + 2H₂=2NH₃(reversible cov tshuaj tiv thaiv). Hom kev tau txais ammonia no hu ua Haber cov tshuaj tiv thaiv. Rau molecular nitrogen thiab hydrogen kom hnov, lawv yuav tsum tau rhuab mus rau 500 ᵒC los yog 932 ᵒF, MPA siab ntawm 25-30 yuav tsum tau ua. Cov hlau ntxeem tau yuav tsum muaj raws li cov khoom siv.
Txais hauv chav kuaj yog cov tshuaj tiv thaiv ntawm ammonium chloride thiab calcium hydroxide: CA(OH)₂ + 2NH₄Cl=CaCl₂ + 2NH₄OH (raws li NH₄OH yog ib qho tsis muaj zog, nws tam sim ntawd decomposes rau hauv gaseous ammonia₄ thiab dej: NH. NH₃ + H₂O).
Ammonia oxidation cov tshuaj tiv thaiv
Lawv pib nrog kev hloov pauv hauv lub xeev oxidation ntawm nitrogen. Txij li thaum ammonia yog qhov zoo txo qis, nws tuaj yeem siv los txo cov hlau hnyav los ntawm lawv cov oxides.
Hlau txo: 2NH₃ + 3CuO=3Cu + N₂ + 3H₂O (Thaum tooj liab (II) oxide yog rhuab nyob rau hauv lub xub ntiag ntawm ammonia, liab tooj liab hlau txo).
Oxidation ntawm ammonia nyob rau hauv muaj cov oxidizing muaj zog (piv txwv li, halogens) tshwm sim raws li qhov sib npaug: 2NH₃ + 3Cl₂=N₂ + 6HCl (qhov no redox cov tshuaj tiv thaiv yuav tsum tau cua sov). Thaum raug cov poov tshuaj permanganate ntawm ammonia hauv nruab nrab alkaline, kev tsim cov molecular nitrogen, poov tshuaj permanganate thiab dej tau pom: 2NH₃ + 6KMnO₄ + 6KOH=6K₂MnO₄ + N₂ + 6H₂O.
Thaum cua kub hnyav (txog 1200 ° C lossis 2192 ᵒF), ammonia tuaj yeem decompose rau hauv cov khoom yooj yim: 2NH₃=N₂ + 3H₂. Ntawm 1000 oC lossis 1832 ammonia reacts nrog methane CH4: 2CH₄ + 2NH₃ + 3O₂=2HCN + 6H₂O (hydrocyanic acid thiab dej). Los ntawm oxidizing ammonia nrog sodium hypochlorite, hydrazine H₂X₄ tuaj yeemget: 2NH3 + NaOCl=N2H4 + NaCl + H 2O
Kev sib xyaw ntawm ammonia thiab nws cov catalytic oxidation nrog oxygen
Oxidation ntawm ammonia nrog oxygen muaj qee yam nta. Muaj ob hom oxidation: catalytic (nrog catalyst), ceev (kub).
Thaum kub hnyiab, cov tshuaj tiv thaiv redox tshwm sim, cov khoom uas yog molecular nitrogen thiab dej: 4NH3 + 2O2=2N2 + 6H2O tus kheej ignition ntawm ammonia). Catalytic oxidation nrog oxygen kuj tshwm sim thaum rhuab (kwv yees li 800 ᵒC los yog 1472 ᵒF), tab sis ib qho ntawm cov tshuaj tiv thaiv cov khoom sib txawv: 4NH₃ + 5O₂=4NO + 6H₂O (nyob rau hauv lub xub ntiag ntawm platinum los yog oxides ntawm hlau, manganese, chromium los yog chromium. ib qho catalyst, cov khoom oxidation yog oxide nitrogen (II) thiab dej).
Xav txog homogeneous oxidation ntawm ammonia nrog oxygen. Uncontrolled monotonous oxidation ntawm ammonia gas seem yog ib qho tshuaj tiv thaiv qeeb. Nws tsis tau tshaj tawm kom meej, tab sis qhov qis dua qhov txwv ntawm ammonia-cua sib tov ntawm 25 ° C yog li 15% hauv qhov siab ntawm 1-10 bar thiab txo qis thaum pib kub ntawm cov roj sib tov nce.
Yog CNH~ yog cov feem mole ntawm NH3 nyob rau hauv cov huab cua-ammonia sib tov nrog kub tmixed (OC), ces los ntawm cov ntaub ntawv CNH=0.15-0 nws raws li nram no tias qhov flammability txwv tsawg. Yog li ntawd, nws yog tsim nyog los ua hauj lwm nrog ib tug txaus margin ntawm kev nyab xeeb nyob rau hauv lub qis qisflammability, raws li txoj cai, cov ntaub ntawv ntawm kev sib xyaw ammonia nrog huab cua feem ntau nyob deb ntawm qhov zoo.
tshuaj muaj zog
Xav txog kev sib cuag oxidation ntawm ammonia rau nitric oxide. Cov tshuaj lom neeg cov tshuaj tiv thaiv nrog ammonia yam tsis hloov lub xeev oxidation nitrogen:
- Reaction nrog dej: NH₃ + H₂O=NH₄OH=NH₄⁺ + he⁻ (cov tshuaj tiv thaiv yog thim rov qab vim ammonium hydroxide NH₄OH yog ib qho tsis ruaj khov).
- Reaction nrog cov kua qaub los tsim cov ntsev ib txwm muaj thiab acidic: NH₃ + HCl=NH₄Cl (ib txwm ammonium chloride ntsev yog tsim); 2NH₃ + H₂SO₄=(NH₄)₂SO₄.
- Cov tshuaj ntsev ntsev ntawm cov hlau hnyav los ua cov complexes: 2NH₃ + AgCl=[Ag(NH₃)₂]Cl (cov khoom siv nyiaj nyuaj (I) diamine chloride forms).
- Reaction nrog haloalkanes: NH3 + CH3Cl=[CH3NH3]Cl (methylammonium hydrochloride forms yog cov hloov ammonium ion NH4=).
- Reaction nrog alkali hlau: 2NH₃ + 2K=2KNH₂ + H₂ (forms potassium amide KNH₂; nitrogen tsis hloov lub xeev oxidation, txawm tias cov tshuaj tiv thaiv redox). Cov tshuaj tiv thaiv ntxiv tshwm sim nyob rau hauv feem ntau yam tsis hloov lub xeev oxidation (tag nrho cov saum toj no, tshwj tsis yog qhov kawg, raug cais los ntawm hom no).
Zoo kawg
Ammonia yog ib yam khoom nrov uas siv rau hauv kev lag luam. Niaj hnub no nws nyob ib qho chaw tshwj xeeb hauv peb lub neej,txij li thaum peb siv feem ntau ntawm nws cov khoom txhua hnub. Kab lus no yuav yog ib qho tseem ceeb nyeem rau ntau tus uas xav paub txog dab tsi nyob ib puag ncig peb.
