Iqhaza kanye Nezinqubo ze-Sodium Cyanide ku-Organic Synthesis

Isingeniso

Sodium I-Cyanide (I-NaCN), i-crystalline emhlophe eqinile encibilika kakhulu emanzini, iyisisekelo esiqinile kanye ne-nucleophile enamandla, okuyenza ibe i-reagent ebalulekile I-Organic synthesis. Naphezu kobuthi bayo obudlulele, obudinga izinyathelo zokuphepha eziqinile ngesikhathi sokuphatha, I-sodium cyanide idlala indima ebalulekile ekwakhiweni kwezinhlanganisela zezinto eziphilayo ezihlukene, okuhlanganisa imithi, amakhemikhali ezolimo, kanye nama-polymers.

Indima ye-Sodium Cyanide ku-Organic Synthesis

I-Cyanide Ion njenge-Nucleophile

The i-cyanide ion ngaphakathi I-Sodium Cyanide iyinucleophile esebenza kakhulu. Ngenxa yokushajwa okungekuhle ku-athomu ye-carbon kanye namandla aphezulu e-electronegativity ye-athomu ye-nitrogen, ingahlasela izikhungo ze-electrophilic kuma-molecule ephilayo, njengamaqembu e-carbonyl, i-alkyl halides, nama-epoxides.

Ukwakhiwa kwamabhondi e-C - C

Omunye wemisebenzi ebaluleke kakhulu ye i-sodium cyanide ku-organic synthesis wukwakhiwa kwebhondi entsha ye-carbon - carbon, etholakala ngokushintshwa kwe-nucleophilic kanye nokusabela kokwengeza. Ngokwesibonelo, lapho i-alkyl halide isabela ne-sodium cyanide, i-cyanide ion ithatha indawo ye-halide ion, okuholela ekwakhekeni kwe-nitrile. Lokhu kusabela kunikeza indlela elula yokwethula i-athomu ye-carbon eyengeziwe ku-molecule. Kamuva, iqembu le-nitrile lingaguqulwa libe amanye amaqembu asebenzayo njengama-carboxylic acid, ama-amine, noma ama-aldehydes ngezinqubo ezihlukahlukene zamakhemikhali.

Ukuhlanganiswa kwe-Amino Acids - Ukusabela kwe-Strecker

I-sodium cyanide iyingxenye eyinhloko ekuphenduleni kwe-Strecker, esetshenziselwa ukuhlanganiswa kwe-α - amino acid. Kule ndlela yokusabela, i-aldehyde noma i-ketone ihlangana ne-ammonium chloride ne-sodium cyanide ukwenza i-α - amino nitrile. Le α - amino nitrile ingabese igaywa nge-hydrolyzed ukuze ikhiqize i-α - amino acid ehambisanayo.

Ukusabela kuvela ngezinyathelo ezimbalwa: Okokuqala, iqembu le-carbonyl le-aldehyde noma i-ketone lidlula i-protonation, okwandisa i-electrophilicity yalo. Khona-ke, i-molecule ye-ammonia ihlasela iqembu le-protonated carbonyl, elandelwa ukuchithwa kwe-deprotonation ukuze yakhe i-hemiaminal. Okulandelayo, iqembu le-hydroxyl le-hemiaminal likhishwa nge-protonated, okuholela ekuqedweni kwamanzi kanye nokwakheka kwe- an ioni ye- an hemia. I-cyanide ion ibese ihlasela i-ganium ion ukuze ikhiqize i-α - amino nitrile. Ekugcineni, i-hydrolysis ye-α - amino nitrile phambi kwe-asidi noma isisekelo inikeza i-α - amino acid.

I-synthesis of Nitriles evela ku-Aryl Halides - I-Rosenmund - von Braun Reaction

Ekuphenduleni kwe-Rosenmund - von Braun, i-sodium cyanide isetshenziselwa ukuguqula i-aryl halides, okungama-halogen - ama-compounds anuka kamnandi, abe yi-aryl nitriles. Icutshungulwa yi-copper(I) cyanide futhi ngokuvamile idinga amazinga okushisa aphezulu, lokhu kusabela kuhilela ukwakheka kwe-copper - aryl intermediate. I-cyanide ion evela ku-sodium cyanide bese isabela nalokhu okuphakathi ukuze yakhe i-aryl nitrile. Le nqubo ibalulekile ekwethuleni iqembu elisebenzayo le-nitrile eringini enephunga elimnandi, elingase liphinde lilungiswe ukuze kuhlanganiswe izinhlanganisela ezihlukahlukene ezinuka kamnandi, ezifana nemithi kanye nodayi.

Ukuhlanganiswa Kwezinhlanganisela zeCarbonyl

I-sodium cyanide nayo ibamba iqhaza ekuhlanganiseni ama-carbonyl compounds. Isibonelo, uma isabela nge-epoxide, i-ion ye-cyanide ihlasela i-athomu yekhabhoni efakwe endaweni encane yeringi ye-epoxide, okubangele ukuthi indandatho ivuleke. I-hydrolysis elandelayo ye-cyanohydrin ewumphumela ingaholela ekwakhekeni kwe-carbonyl compound.

Izindlela Zokusabela Ezibandakanya I-Sodium Cyanide

I-Nucleophilic Substitution Reactions

I-SN2 Mechanism: Uma i-sodium cyanide iphendula ne-alkyl halides eyinhloko, ukusabela kuvamise ukulandela indlela ye-SN2 (bimolecular nucleophilic substitution). I-cyanide ion ihlasela i-athomu ye-carbon exhunywe ku-halogen ukusuka ngemuva, ngokuphambene nendawo ye-halide ion eshiya. Lokhu ukusabela okuhlangene lapho ukuphulwa kwebhondi ye-carbon - halogen kanye nokwakheka kwebhondi ye-carbon - cyanide kwenzeka ngesikhathi esisodwa. Izinga lokusabela lincike ekugxiliseni kwakho kokubili i-alkyl halide ne-cyanide ion, futhi i-stereochemistry yomkhiqizo ihlanekezelwe uma iqhathaniswa neyokuqala.

I-SN1 Mechanism: Nge-alkyl halide ephakeme, ukusabela kungase kuqhubeke ngendlela ye-SN1 (unimolecular nucleophilic substitution). Okokuqala, i-alkyl halide iyahlukana ukuze yakhe indawo ephakathi nendawo ye-carbocation. Khona-ke, i-cyanide ion ihlasela le carbocation ukuze yakhe umkhiqizo. Indlela ye-SN1 ibonakala ngokwakhiwa kwe-planar carbocation emaphakathi, futhi umkhiqizo ungase ubonise ingxube ye-stereochemistries, into eyaziwa ngokuthi i-racemization, ngenxa yokuhlasela kwe-nucleophile kusuka ezinhlangothini zombili ze-planar carbocation.

I-Nucleophilic Addition Reactions

Ukwengezwa kumaqembu e-Carbonyl: Uma i-sodium cyanide iphendula ne-aldehydes noma ama-ketones, i-ion cyanide iqondise ku-athomu ye-electrophilic carbonyl carbon. Iqembu le-carbonyl line-polarized carbon - ibhondi ye-oxygen, ne-athomu ye-carbon iyindawo ye-electrophilic. Ukuhlaselwa kwe-ion ye-cyanide kudala ibhondi entsha ye-carbon - cyanide, futhi i-athomu yomoya-mpilo yeqembu le-carbonyl ithola icala elibi. Esinyathelweni esilandelayo, umthombo we-proton, njengamanzi noma i-asidi, ukhiqiza i-athomu ye-oxygen ukuze wenze i-cyanohydrin. Lokhu kusabela kuyabuyiseleka emuva, futhi ukulingana kungalungiselelwa emkhiqizweni ngokulawula izimo zokusabela.

Ukwengezwa kwe-Imines: Ekuphenduleni kwe-Strecker, ukungezwa kwe-ion ye-cyanide ku-inoni i-inonium, eyakhiwe ngenxa yokusabela kwe-aldehyde noma i-ketone ene-ammonia, kulandela indlela efanayo yokwengeza i-nucleophilic. I-ioni ye-finium ineshaje elihle ku-athomu ye-nitrogen, okwenza i-athomu ye-carbon athomu eseduze ibe yi-electrophilic. I-cyanide ion ihlasela le athomu yekhabhoni, yakhe ibhondi entsha ye-carbon - cyanide futhi okuholela ekwakhekeni kwe-α - amino nitrile.

Ukucatshangelwa Kwezokuphepha

Kubalulekile ukugcizelela ukuthi i-sodium cyanide inobuthi kakhulu. Ukuhogela, ukuwungenisa, noma ukuthintana nawo esikhumbeni kungabulala. Lapho usebenza ne-sodium cyanide, izimiso zokuphepha eziqinile kufanele zilandelwe. Lokhu kuhlanganisa ukwenza izivivinyo endaweni engenisa umoya kahle, ukugqoka izinto zokuzivikela ezifanele njengamagilavu, izibuko, nejazi laselabhu, kanye nokuba nezinhlelo ezifanele zokusabela ezimweni eziphuthumayo uma kwenzeka uchayeka ngengozi.

Isiphetho

I-sodium cyanide iyi-reagent enamandla futhi eguquguqukayo ku-organic synthesis. Ikhono layo lokusebenza njenge-nucleophile futhi lidale amabhondi ekhabhoni amasha alenza libe yithuluzi elibaluleke kakhulu kosokhemisi ekuhlanganiseni inhlanganisela ebanzi yezinto eziphilayo. Ukuqonda izindlela zokusabela ezibandakanya i-sodium cyanide kubalulekile ekuklameni imizila yokwenziwa ephumelelayo nokubikezela imiphumela yokusabela. Kodwa-ke, ngenxa yobuthi bayo obuphezulu, ukusetshenziswa kwayo kufanele kulawulwe ngokucophelela futhi kwenziwe ngezinyathelo zokuphepha ezisezingeni eliphezulu ukuze kuvikelwe inhlalakahle yosokhemisi nemvelo.