《溶胶ndSolu》PPT课件

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1、溶胶凝胶化学与工程引论A.C.Pierre,IntroductiontoSol-gelProcessing(ChemistryandEngineering)主讲：夏长荣，电话3607475，材料楼北217室，Email:xiacr@ustc.edu.cn辅导：王运龙，wylbinhe@mail.ustc.edu.cn考试（60％），不参加考试不计成绩；分组专题报告（40％）；上课12周，签到8次以上，签到8次以下不计成绩。Simplifiedchartofsol-gelprocessesThechemistr

2、yofprecursorssolutionsAlltypesofprecursorscanbeused,providedtheyaremiscible.MetallicsaltMmXn,AlCl3,(NH4)2Ce(NO3)6.Alkoxides,Al(OC2H5)3,Si(OCH3)4Organometalliccompounds1.SolventsWaterNonaqueoussolvents水是最好的极性溶剂之一，主要原因是什么？举3个非水溶剂的例子？极性溶剂和非极性溶剂的主要区别是什么？酸性、碱性、二

3、性溶剂有何区别？举例说明Protic,Aprotic,amphoteric（质子性、非质子性、两性）溶剂？Water,H2OTheangleHOHis104.5ointhegaseousstate,andvariesfrom118oto120ointheliquidstate.Dipolemoment,=1.85D(1Debye=3.33610-30C·m)3a1isdelocalized,Lewisbase,donatingapairofelectrons1b1isnonbinding,aweakdo

4、norNegativepartialchargeofoxygenatomof(O)=-0.4Positivepartialcharge(H)=+0.2ResultsofpolarstructureIWaterisanexcellentliquidmediuminwhichtodissolveionicsolutes0=8.854210-12F·m-1,thedielectricpermittivityofvacuumr,therelativedielectricconstant,r,H2O=78.

5、4;itconsequentlylargelyattenuatesthecoulombinteractionbetweentwoelectricalcharges.ResultsofpolarstructureIIMoleculesareboundbyupto4hydrogenbondstoneighboringmolecules.Furtherincreasetheabilitytodissolveionicsolutes.Auto-dissociate2H2OH3O++HO-Kw=[H3O+][HO-]

6、=10-14at25oC[H3O+][H9O4+][HO-][H7O4-]Inconsequence,O2-practicallydoesnotexistinwater,andwhenasolidoxideisdissolveditimmediatelyundergoanacidbaseprotonationreactionNonaqueoussolventsNonaqueoussolventsr>40,Suchmolecularshavegoodionizingpropertiesandcanther

7、eforedissolveotherpolarsoluter<20,ThesemolecularshaveaweakionizingpropertyandcanonlydissovelesspolarsoluteClassificationProtic;exchangeaproton,acidic;donateaprotonoracceptapairofelectronsAprotic;cannotexchangeaproton,base;acceptaprotonordonateapairofelectr

8、onsAsolventisamphotericwhenitcanbehavebothasabaseandasanacid.AmphotericsolventsMineralacids(HCN,HX,HNO3,H2SO4,H2S)CarboxylicacidsR-COOHWater,thefirstalcohols(CH3OH,C2H5OH,…),andphenolC6H5OHAmmoniaNH3an