Phosphoric acid, tseem hu ua orthophosphoric acid, yog ib hom inorganic acid, nruab nrab muaj zog acid, tshuaj formula H3PO4, molecular hnyav 97.994. Nws tsis yooj yim rau volatilize, decompose, thiab yuav luag tsis muaj oxidation. Nws muaj cov khoom sib xws ntawm acid. Nws yog ternary tsis muaj zog acid, uas tsis muaj zog tshaj li hydrochloric acid, sulfuric acid, nitric acid, tab sis muaj zog tshaj acetic acid, boric acid, thiab lwm yam. Phosphoric acid yog yooj yim deliquescent hauv huab cua. Pyrophosphoric acid yog tau los ntawm cua sov, thiab metaphosphoric acid yog tau los ntawm lub cev qhuav dej ntxiv. Phosphoric acid feem ntau yog siv rau hauv kev lag luam, zaub mov, chiv thiab lwm yam lag luam, xws li xeb inhibitor, khoom noj khoom haus additive, kho hniav thiab orthopedic phais, EDIC corrosion agent, electrolyte, flux, dispersant, industrial corrosion agent, chiv raw cov ntaub ntawv thiab cov khoom siv tu tsev. cov khoom, nrog rau cov tshuaj reagent.
Orthophosphate yog phosphoric acid tsim los ntawm ib qho phosphorus oxygen tetrahedron. Nyob rau hauv phosphoric acid molecule, P atom yog sp3 hybrid, thiab peb hybrid orbitals tsim peb nrog oxygen atom σ Lwm PO daim ntawv cog lus yog tsim los ntawm σ Thiab ob dp bonds ntawm oxygen mus rau phosphorus. σ Cov kev sib koom ua ke yog tsim los ntawm kev sib koom ua ke ntawm ib khub ntawm ib leeg electrons ntawm phosphorus atom mus rau qhov khoob ntawm cov pa oxygen atom. D ← p daim ntawv cog lus yog tsim los ntawm kev sib tshooj ntawm ob khub ntawm ib leeg electrons ntawm py thiab pz orbitals ntawm oxygen atom thiab dxz thiab dyz khoob orbitals ntawm phosphorus atom. Txij li thaum 3d lub zog theem ntawm phosphorus atom yog ntau dua li 2p lub zog ntawm oxygen atom, lub molecular orbital tsim tsis zoo heev, yog li PO daim ntawv cog lus yog triple daim ntawv cog lus, tab sis ntawm ib daim ntawv cog lus thiab ob daim ntawv cog lus ntawm daim ntawv cog lus. lub zog thiab daim ntawv cog lus ntev. Ob leeg ntshiab H3PO4 thiab nws cov siv lead ua hydrate muaj hydrogen bonds, uas tej zaum yuav yog vim li cas vim li cas cov concentrated phosphoric acid kua yog khov.
Specific conductance
Nyob rau hauv chav tsev kub (219K), thaum lub concentration ntawm H3PO4 tov yog 45 feem pua - 47 feem pua, qhov tshwj xeeb conductance yog qhov siab tshaj plaws.
Crystallization point:
Phosphoric acid belongs rau nruab nrab muaj zog acid, thiab nws crystallization point (kub point) yog 21 degree. Thaum nws qis dua qhov ntsuas kub no, nws yuav ua rau cov dej khov hemihydrate (ice) precipitate. Tau kawg, phosphoric acid feem ntau tsis tsim (ice) crystals ntawm qhov kub siab tshaj 10 degree lossis qis dua. Qhov no yog vim phosphoric acid muaj cov yam ntxwv ntawm supercooling, uas yog, thaum qhov tseeb phosphoric acid nyob rau hauv lub lag luam yog qis dua 21 degree, nws yuav deviate los ntawm nws tsim (ice) crystal point thiab yuav tsis tsim (ice) crystals tam sim ntawd. Txawm li cas los xij, ntev npaum li qhov ntsuas kub tsawg yog khaws cia rau ib lub sijhawm, phosphoric acid yog ib qho yooj yim los tsim cov dej khov nab kuab nyob rau hauv lub xeev zoo li qub.
Phosphoric acid siv lead ua, zoo li lwm cov kua siv lead ua kua, belongs rau lub cev hloov pauv tsis yog tshuaj hloov pauv. Nws cov khoom siv tshuaj yuav tsis hloov vim crystallization, uas yog, cov khoom ntawm phosphoric acid yuav tsis cuam tshuam vim crystallization. Nws tseem tuaj yeem siv tau ib txwm yog tias qhov kub tau muab rau yaj lossis dej kub yog siv los dilute thiab yaj.
Crystallization yam ntxwv: siab phosphoric acid concentration, siab purity thiab siab crystallinity. Raws li kev paub dhau los, thaum qhov kub siab tshaj lossis qis dua 4 degree thiab qhov concentration siab dua 85 feem pua, nws cov crystallinity nce. Yog tias nws tau sib xyaw ua ke nrog crystalline phosphoric acid, nws yuav ua rau cov phosphoric acid tsis muaj siv lead ua (ice) kom kis tau sai sai thiab tsim siv lead ua (ice). Tsis tas li ntawd, phosphate crystal (ice) yog txawv txav ceev, uas yuav ua rau feem ntau ntawm cov phosphoric acid cia ntim rau hauv crystal (ice). Tom qab cov phosphoric acid crystals (ice) yog tsim, phosphoric acid nyob rau hauv lub Upper ib feem yuav dilute, thiab cov acicular crystal ntshiab phosphoric acid yog tso rau hauv qis. Raws li kev paub dhau los, 75 feem pua phosphoric acid kuj nyuaj rau tsim (ice) crystals ntawm qhov kub thiab txias (nyob ib ncig ntawm 4 degree), yog li nws pom zoo kom siv 75 feem pua phosphoric acid ntawm qhov kub thiab txias.
Zoo li dej khov, phosphoric acid (ice) siv lead ua yog nws tus kheej lub cev thiab tus cwj pwm, uas tsis tuaj yeem hloov pauv. Tsuas yog khaws cia thiab kho kom zoo tuaj yeem tiv thaiv (ice) crystal tsim. Kev lag luam phosphoric acid yog cov kua nplaum uas muaj 85 feem pua H3PO4. Crystallization los ntawm cov tshuaj concentrated yuav tsim cov semi hydrate 2H3PO4 · H2O (melting point 302.3K).
Kev ua liaj ua teb: phosphoric acid yog cov khoom siv raw rau kev tsim cov phosphate chiv tseem ceeb (calcium superphosphate, potassium dihydrogen phosphate, thiab lwm yam), thiab tseem yog cov khoom siv raw rau kev tsim cov khoom noj khoom haus (calcium dihydrogen phosphate).
Kev lag luam: Phosphoric acid yog ib qho tseem ceeb ntawm cov khoom siv raw, thiab nws cov haujlwm tseem ceeb yog raws li hauv qab no:
1. Cov hlau saum npoo yog kho los tsim cov phosphate zaj duab xis insoluble ntawm cov hlau nto los tiv thaiv cov hlau los ntawm corrosion.
2. Nws yog tov nrog nitric acid raws li ib tug tshuaj polishing neeg sawv cev los txhim kho lub smoothness ntawm hlau nto.
3. Phosphate ester, raw khoom rau kev tsim cov khoom siv ntxhua khaub ncaws thiab tshuaj tua kab.
4. Cov khoom siv raw rau kev tsim cov phosphorus uas muaj cov nplaim hluav taws.
Khoom noj khoom haus: Phosphoric acid yog ib qho ntawm cov khoom noj ntxiv. Raws li tus neeg sawv cev qaub thiab cov poov xab hauv cov zaub mov, cola muaj phosphoric acid. Phosphate kuj yog ib qho khoom noj khoom haus tseem ceeb, uas tuaj yeem siv los ua cov khoom noj khoom haus ntxiv.
Tshuaj: Phosphoric acid tuaj yeem siv los tsim cov phosphorus uas muaj cov tshuaj, xws li sodium glycerophosphate.