Lewis Acids uye Zvigadziko: Dzidziso, Mashandisirwo, uye Kukosha muKemistri
Pendauluan
Mukemistri, pfungwa dzemaacids nemabhesi dzave dzichizivikanwa uye dzichishandiswa kwemazana emakore. Dzidziso dzakasiyana-siyana dzakagadzirwa kutsanangura hunhu uye maitiro emaacids nemabhesi. Imwe dzidziso yakapesvedzera zvikuru uye yakashandiswa zvakanyanya idzidziso yeLewis acid-base. Pfungwa iyi haingowedzere tsananguro dzemaacids nemabhesi chete asiwo inovhura nzira yekunzwisisa kwakadzama kwemaitiro emakemikari uye kudyidzana kwemamorekuru. Chinyorwa chino chichakurukura dzidziso yeLewis acid-base, mashandisirwo ayo, uye kukosha kwayo mukemistri.
Lewis Acids uye Zvigadziko: Tsanangudzo uye Pfungwa Dzekutanga
Dzidziso yeLewis acid-base yakatangwa naGilbert N. Lewis muna 1923. Kusiyana nedzidziso yeBronsted-Lowry iyo inotsanangura maasidhi semaproton donors (H⁺) uye mabhesi semaproton anogamuchira, dzidziso yaLewis inotora nzira yakajairika nekutsanangura maasidhi nemabhesi zvichibva pamaerekitironi maviri:
– Asidhi yeLewis imhando yemakemikari inogona kugamuchira maerekitironi maviri.
- Lewis base rudzi rwemakemikari runogona kupa maerekitironi maviri.
Muenzaniso wakapfava weLewis acid nebase ndeyekuita pakati peboron trifluoride (BF₃) neammonia (NH₃). Mukuita uku, BF₃ inoshanda seLewis acid nekuti atomu yeboron ine orbital isina chinhu inogona kugamuchira electron pair, nepo NH₃ inoshanda seLewis base nekuti atomu yenitrogen ine electron pair imwe chete yainogona kupa.
Maumbirwo uye Maerekitironi: Kiyi yekunzwisisa Lewis Acids uye Zvigadziko
Chaizvoizvo, dzidziso iyi inogona kushandiswa kutsanangura kudyidzana kwemakemikari nekutarisa chimiro chemagetsi chemaatomu kana mamorekuru anobatanidzwa. Maasidhi eLewis anowanzova marudzi ane maorbital asina chinhu kana asina vanhu anogona kukwezva maerekitironi maviri kubva kumabhesi eLewis. Semuenzaniso:
– AlCl₃ (Aluminium trichloride): AlCl₃ iLewis acid nekuti atomu yealuminium ine orbital isina chinhu inogona kugamuchira maerekitironi.
– H₂O (Mvura): Kana paine maerekitironi maviri chete ari paokisijeni, mvura inogona kushanda seLewis base muzviitiko zvakawanda.
Pfungwa iyi inogonawo kutsanangura macompounds akaomarara uye maitiro akaomarara ekubatana. Semuenzaniso, maion esimbi anochinjika anowanzo shanda seLewis acids mukuita kwekubatana, uko anogamuchira maerekitironi maviri kubva kuma ligands anoshanda seLewis bases.
Kushandiswa kweLewis Acid-Base Theory muKemistri
1. Kugadzirwa kweMakemikoro
Mukugadzirwa kwemakemikari, dzidziso yaLewis inobatsira zvikuru mukugadzira maitiro emakemikari uye kunzwisisa mashandiro ekuita. Semuenzaniso, mukuita kweFriedel-Crafts, AlCl₃ inoshanda se catalyst, uye seLewis acid, inobatsira mukugadzirwa kwe electrophilic complex inodiwa kuti maitiro aenderere mberi.
2. Kemistri Yekubatanidza
Kemikari yekubatanidza, iyo inosanganisira transition metal complexes, inobatsira zvikuru kubva kuLewis theory. Transition metals inowanzo shanda seLewis acids uye complex ine ligands dzinopa maerekitironi maviri. Kunzwisisa kudyidzana uku kunobvumira machemist kugadzira nekugadzira mhando dzakasiyana dzesimbi dzine hunhu hwaunoda.
3. Kugadzirisa
Maitiro mazhinji ekugadzirisa zvinhu anoshandisa Lewis acid-base principle. Semuenzaniso, maLewis acid catalysts anoshandiswa mu olefin polymerization, uko catalyst inobatsira mukuwedzera ma monomers kune polymer chain iri kukura. Iyi dzidziso inoshandiswawo mukugadzira catalyst ye organic reactions, senge hydrogenation, oxidation, uye dehydrogenation.
4. Kemikari yeOrganic
Mu organic chemistry, dzidziso yaLewis inobatsira kunzwisisa mashandiro e reaction. Semuenzaniso, mu nucleophilic addition reaction kune carbonyl, carbonyl group inoshanda seLewis acid nepo nucleophile inoshanda seLewis base. Kunzwisisa kuumbwa uye reactivity ye intermediates idzi kwakakosha pakugadzira nzira dzinoshanda dze organic synthesis.
Maitiro eLewis Acid-Base muAqueous Solution
Kunyangwe dzidziso yeLewis acid-base ichiwanzo shandiswa pakuita zvinhu mugasi kana muzvinhu zvisinganyungudutsi mvura, kushandiswa kwayo muzvinhu zvine mvura kwakakoshawo. Muenzaniso kuumbwa kweionic complexes mumvura. Mamwe maion esimbi, akadai seFe³⁺, anoshanda seLewis acids akasimba uye anogona kubatana nemamorekuru emvura (Lewis bases) kugadzira maaquacomplexes akadai se[Fe(H₂O)₆]³⁺.
Matambudziko uye Kutsoropodzwa kweLewis Acid-Base Theory
Pasinei nekushandiswa kwayo kwose kwose, dzidziso yeLewis acid-base haina kutsoropodzwa uye miganhu yayo. Dambudziko guru nderekuti dzidziso iyi dzimwe nguva inonyanya kuwanda uye haiwanzopa fungidziro dzehuwandu dzakavimbika. Uyezve, mamwe maitiro anokonzerwa nezvimwe zvinhu, zvakaita semhedzisiro yesteric kana entropy, angasatsanangurwe zvizere nedzidziso yeLewis.
1. Kushaikwa kweKuyera kweHuwandu
Kusiyana nepfungwa yeBronsted-Lowry, iyo inogona kuyerwa uchishandisa pKa values, simba reLewis acid-base harina chiyero chakaenzana chehuwandu. Izvi zvinoita kuti zviome kuenzanisa simba remaacid kana mabhesi mumamiriro akasiyana.
2. Kureruka Kwakanyanya
Nekuti inotsanangura maasidhi nemabhesi chete zvichibva pakugamuchirwa kwemaerekitironi maviri uye kupa, dzidziso iyi dzimwe nguva inoonekwa seinorerutsa kudyidzana kwemakemikari kwakaoma, kunyanya mumasisitimu ezvipenyu kana zvinhu zvinoratidza kudyidzana kwakawanda.
Penutup
Dzidziso yeLewis acid-base ndiyo nheyo huru yekemikari yemazuva ano. Netsananguro dzayo dzakajairika uye dzinochinjika dzemaacids nemabases, dzidziso iyi inoita kuti munhu anzwisise zvakadzama maitiro akasiyana-siyana emakemikari, kubva pakugadzirwa kwezvinhu zvakasanganiswa kusvika kuzvinhu zvinobatanidza simbi. Pasinei nekusakwana kwayo, mashandisirwo edzidziso yeLewis acid-base achiri kukosha uye akakosha pakutsvagisa nekukura kwekemikari kuri kuramba kuchikura. Nekushandisa kwakakodzera uye kunzwisisa kwakakwana, dzidziso iyi inoramba iri chishandiso chinokosha kune vanoongorora makemikari pasi rese.
