COV KHOOM NOJ UAS UAS UA KOM NTAU, COV NEEG LIM, THIAB COV NEEG ZAUB MOV QHUAV
Cov ntxaij lim dej molecular yog cov hlau crystalline aluminosilicates uas muaj peb sab sib txuas ua ke ntawm silica thiab alumina tetrahedra. Cov dej ntuj ntawm cov dej noo raug tshem tawm ntawm lub network no los ntawm kev ua kom sov los tsim cov qhov sib npaug uas xaiv cov molecules ntawm qhov loj me tshwj xeeb.
Feem ntau siv lub sieve 4 txog 8-mesh rau hauv cov ntawv thov gasphase, thaum hom 8 txog 12-mesh feem ntau siv rau hauv cov ntawv thov liquidphase. Cov hmoov ntawm cov sieves 3A, 4A, 5A thiab 13X yog tsim rau cov ntawv thov tshwj xeeb.
Paub ntev txog lawv lub peev xwm ziab (txawm tias txog 90 ° C), cov molecular sieves tsis ntev los no tau ua pov thawj tias muaj txiaj ntsig zoo hauv cov txheej txheem organic synthetic, feem ntau tso cai rau kev rho tawm cov khoom xav tau los ntawm cov tshuaj condensation uas raug tswj hwm los ntawm kev sib npaug tsis zoo. Cov zeolites hluavtaws no tau pom tias tshem tawm dej, cawv (suav nrog methanol thiab ethanol), thiab HCl los ntawm cov kab ke xws li ketimine thiab enamine syntheses, ester condensations, thiab kev hloov pauv ntawm unsaturated aldehydes rau polyenals.
| Hom | 3A |
| Kev sau ua ke | 0.6 K2O: 0.40 Na2O: 1 Al2O3: 2.0 ± 0.1SiO2: x H2O |
| Kev piav qhia | Daim ntawv 3A yog ua los ntawm kev hloov cov potassium cations rau cov sodium ions uas muaj nyob hauv 4A qauv, txo qhov loj me ntawm qhov pore kom ~ 3Å, tsis suav nrog txoj kab uas hla > 3Å, piv txwv li, ethane. |
| Cov Ntawv Thov Tseem Ceeb | Kev ziab cov dej hydrocarbon uas tsis tau saturated, suav nrog cov roj tawg, propylene, butadiene, acetylene; ziab cov kua polar xws li methanol thiab ethanol. Kev nqus cov molecules xws li NH3 thiab H2O los ntawm N2/H2 ntws. suav tias yog tus neeg sawv cev ziab dav dav hauv cov xov xwm polar thiab nonpolar. |
| Hom | 4A |
| Kev sau ua ke | 1 Na2O: 1 Al2O3: 2.0 ± 0.1 SiO2: x H2O |
| Kev piav qhia | Daim ntawv sodium no sawv cev rau tsev neeg hom A ntawm cov molecular sieves. Qhov qhib qhov zoo yog 4Å, yog li tsis suav nrog cov molecules ntawm txoj kab uas hla zoo > 4Å, piv txwv li, propane. |
| Cov Ntawv Thov Tseem Ceeb | Nyiam siv rau kev ziab dej tsis tu ncua hauv cov kua kaw lossis cov roj, piv txwv li, hauv kev ntim tshuaj, cov khoom siv hluav taws xob thiab cov tshuaj lom neeg uas lwj; kev tshem dej hauv cov tshuab luam ntawv thiab cov yas thiab ziab cov hydrocarbon uas saturated. Cov hom adsorbed suav nrog SO2, CO2, H2S, C2H4, C2H6, thiab C3H6. Feem ntau suav tias yog tus neeg sawv cev ziab thoob ntiaj teb hauv cov xov xwm polar thiab nonpolar. |
| Hom | 5A |
| Kev sau ua ke | 0.80 CaO : 0.20 Na2O : 1 Al2O3 : 2.0 ± 0.1 SiO2 : x H2O |
| Kev piav qhia | Cov calcium ions divalent hloov sodium cations muab qhov qhib ntawm ~ 5Å uas tsis suav nrog cov molecules ntawm txoj kab uas hla zoo > 5Å, piv txwv li, tag nrho 4-carbon rings, thiab iso-compounds. |
| Cov Ntawv Thov Tseem Ceeb | Kev sib cais cov paraffins ib txwm muaj los ntawm cov branched-chain thiab cyclic hydrocarbons; kev tshem tawm H2S, CO2 thiab mercaptans los ntawm cov roj av. Cov molecules adsorbed suav nrog nC4H10, nC4H9OH, C3H8 txog C22H46, thiab dichlorodifluoro-methane (Freon 12®). |
| Hom | 13X |
| Kev sau ua ke | 1 Na2O: 1 Al2O3 : 2.8 ± 0.2 SiO2 : xH2O |
| Kev piav qhia | Daim ntawv sodium sawv cev rau cov qauv yooj yim ntawm tsev neeg hom X, nrog rau qhov qhib qhov zoo hauv 910¼ ntau yam. Yuav tsis nqus (C4F9) 3N, piv txwv li. |
| Cov Ntawv Thov Tseem Ceeb | Kev ziab roj rau kev lag luam, kev ntxuav cov nroj tsuag los ntawm huab cua (tshem tawm H2O thiab CO2 tib lub sijhawm) thiab kev ua kom qab zib ntawm cov kua hydrocarbon/gas (tshem tawm H2S thiab mercaptan). |
Lub sijhawm tshaj tawm: Lub Rau Hli-16-2023
