Qhov sib txawv tseem ceeb ntawm lub hauv paus thiab nucleophile yog cov hauv paus yog cov neeg txais cov hydrogen uas tuaj yeem ua cov tshuaj tiv thaiv tsis zoo thaum nucleophiles tawm tsam electrophiles los pib qee cov tshuaj tiv thaiv organic.
Acids thiab hauv paus yog ob lub ntsiab lus tseem ceeb hauv chemistry. Ob leeg muaj contradictory zog. Ib tug nucleophile yog ib lo lus, uas peb siv ntau prominently nyob rau hauv cov organic chemistry los piav txog cov tshuaj tiv thaiv mechanisms thiab tus nqi. Raws li kev tsim qauv, tsis muaj qhov sib txawv ntawm lub hauv paus thiab nucleophile, tab sis ua haujlwm lawv ua haujlwm sib txawv.
Pab yog dab tsi?
Peb tuaj yeem txhais cov hauv paus hauv ntau txoj hauv kev raws li cov ntsiab lus ntawm ntau tus kws tshawb fawb. Arrhenius txhais lub hauv paus ua ib yam khoom uas pub OH– ions rau cov tshuaj. Raws li Lewis, txhua tus neeg pub khoom siv hluav taws xob yog lub hauv paus. Bronsted- Lowry txhais lub hauv paus ua ib yam khoom uas tuaj yeem txais tau ib qho proton. Raws li Arrhenius txhais, ib qho chaw yuav tsum muaj hydroxide anion thiab muaj peev xwm pub dawb los ua hydroxide ion los ua lub hauv paus.
Txawm li cas los xij, raws li Lewis thiab Bronsted- Lowry theories, muaj qee cov molecules, uas tsis muaj hydroxides tab sis tuaj yeem ua lub hauv paus. Piv txwv li, NH3 yog Lewis puag, vim tias nws tuaj yeem pub cov electron khub ntawm nitrogen. Ib yam li ntawd, Na2CO3 yog Bronsted-Lowry puag tsis muaj hydroxide pawg tab sis muaj peev xwm txais hydrogens.
Daim duab 01: Cov Khoom Siv Tshuaj nyob rau hauv Lub Sij Hawm Lub Sijhawm uas tuaj yeem tsim Cov Khoom Nyuaj, Mos thiab Nruab Nrab Nruab Nrab
Txoj kev ntawm Bases
Bases muaj cov xab npum nplawm zoo li kev xav thiab iab saj. Lawv hnov mob yooj yim nrog cov kua qaub ua dej thiab ntsev molecules. Caustic soda, ammonia thiab ci dej qab zib yog qee yam ntawm cov hauv paus uas peb tuaj hla ntau zaus. Peb tuaj yeem faib cov hauv paus rau hauv ob pawg, nyob ntawm lawv lub peev xwm los sib cais thiab tsim cov hydroxide ions. Lub hauv paus muaj zog zoo li NaOH, KOH tuaj yeem ua tiav ionization hauv kev daws teeb meem los muab ions. Cov hauv paus tsis muaj zog xws li NH3 yog ib feem ntawm kev sib cais thiab muab cov hydroxide ions tsawg dua.
Kb is the base dissociation constant. Nws muab ib qho kev qhia txog lub peev xwm poob hydroxide ions ntawm lub hauv paus tsis muaj zog. Cov kua qaub uas muaj pKa tus nqi (ntau tshaj 13) yog cov acids tsis muaj zog, tab sis lawv cov conjugate bases suav tias yog cov hauv paus muaj zog. Txhawm rau xyuas seb cov khoom puas yog lub hauv paus lossis tsis, peb tuaj yeem siv ntau qhov ntsuas xws li litmus ntawv lossis pH ntawv. Bases qhia tus nqi pH siab dua 7, thiab nws hloov liab litmus rau xiav.
Nucleophile yog dab tsi?
Peb tuaj yeem sau npe tsis zoo ion lossis ib qho nruab nrab molecule uas muaj tsawg kawg yog ib qho tsis sib koom ua ke ua ib qho nucleophile. Nucleophile yog ib yam khoom uas muaj electropositive heev, yog li ntawd, nyiam cuam tshuam nrog cov chaw zoo. Nws tuaj yeem pib cov tshuaj tiv thaiv siv ib leeg electron khub. Piv txwv li, thaum ib tug nucleophile reacts nrog ib tug alkyl halide, ib leeg khub ntawm nucleophile tawm tsam cov pa roj carbon atom uas bears lub halogen. Cov pa roj carbon atom no muaj cov nqi zoo ib nrab vim qhov sib txawv ntawm electronegativity ntawm carbon atom thiab halogen atom.
Daim duab 02: Cov tshuaj tiv thaiv ntawm Dicarbamoyl Chloride nrog Nucleophiles
Tom qab cov nucleophile txuas rau cov pa roj carbon, cov halogen tawm. Peb hu cov tshuaj tiv thaiv no ua cov tshuaj tiv thaiv nucleophilic hloov pauv. Muaj lwm hom kev tshwm sim uas pib nrog cov nucleophiles; lawv yog nucleophilic tshem tawm cov tshuaj tiv thaiv. Nucleophilicity qhia txog cov tshuaj tiv thaiv mechanisms. Yog li, nws yog ib qho qhia txog cov tshuaj tiv thaiv. Piv txwv li, yog tias cov nucleophilicity siab, ces qee qhov kev tshwm sim tuaj yeem tshwm sim sai, thiab yog tias cov nucleophilicity tsawg, cov tshuaj tiv thaiv qeeb. Txij li thaum nucleophiles pub electrons, raws li Lewis txhais, lawv yog cov hauv paus.
Qhov txawv ntawm Base thiab Nucleophile yog dab tsi?
Qhov sib txawv loj ntawm lub hauv paus thiab nucleophile nyob ntawm lawv txoj haujlwm. Cov hauv paus yog cov neeg txais hydrogen uas tuaj yeem ua cov tshuaj tiv thaiv tsis zoo thaum cov nucleophiles tawm tsam electrophiles los pib qee cov tshuaj tiv thaiv organic. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm lub hauv paus thiab nucleophile. Ntxiv mus, cov hauv paus ua raws li cov neeg txais hydrogen uas tuaj yeem ua qhov cuam tshuam tsis zoo thaum nucleophiles tua electrophiles los pib qee qhov kev cuam tshuam cov organic.
Raws li lwm qhov sib txawv tseem ceeb ntawm lub hauv paus thiab nucleophile, peb tuaj yeem siv hom tshuaj lom neeg uas lawv koom nrog; bases koom nrog hauv acid neutralizing cov tshuaj tiv thaiv thaum nucleophiles koom nrog hauv cov tshuaj tiv thaiv nucleophilic. Tsis tas li ntawd, cov hauv paus muaj cov tshuaj kinetic uas txhais tau tias, lawv hnov qab nyob ntawm qhov raug nws nyob ntawm. Txawm li cas los xij, nucleophiles muaj cov tshuaj thermodynamic uas txhais tau tias lawv cuam tshuam los ntawm lwm yam tshuaj lom neeg hauv ib puag ncig.
Summary – Base vs Nucleophile
Txhua nucleophile yog lub hauv paus, tab sis txhua lub hauv paus tsis yog nucleophiles. Qhov sib txawv tseem ceeb ntawm lub hauv paus thiab nucleophile yog cov hauv paus yog cov neeg txais hydrogen uas tuaj yeem ua cov tshuaj tiv thaiv tsis zoo thaum nucleophiles tawm tsam electrophiles los pib qee cov tshuaj tiv thaiv organic.
