Izicelo Ezihlukahlukene ze-Sodium Cyanide ku-Organic Synthesis

Isingeniso

Sodium i-cyanide (I-NaCN), enefomula yamakhemikhali i-NaCN, iyikristalu emhlophe eqinile noma impushana encibilika kakhulu emanzini futhi inephunga elimnandi le-alimondi elibabayo. Ngenxa ye-reactivity yayo ephezulu, ithole ukusetshenziswa okubanzi ezinhlobonhlobo ze i-organic synthesis ukusabela. Nokho, kubalulekile ukuqaphela lokho i-sodium cyanide inobuthi ngokwedlulele futhi kufanele iphathwe ngokucophelela okukhulu nangokuhambisana ngokuqinile nezimiso zokuphepha. Lesi sihloko sihlola izinhlelo zokusebenza ezihlukahlukene ze I-Sodium Cyanide ku-organic synthesis.

Izicelo ku-Organic Synthesis

Ukusabela kwe-Strecker

Enye yezinhlelo zokusebenza ezaziwa kakhulu ze I-sodium cyanide ku-organic synthesis iku-Strecker reaction. Lokhu kusabela kuyindlela enamandla yokuhlanganiswa kwe-α - amino acid. Ekuphenduleni kwe-Strecker, i-aldehyde noma i-ketone isabela ne-ammonium chloride (NH₄Cl) ne-sodium cyanide. I-general reaction mechanism imi kanje:

1. Okokuqala, i-aldehyde noma i-ketone isabela ne-ammonia (eyakhiwe ku-situ kusuka ku-ammonium chloride) ukuze yakhe i-imine. I-CarbonIqembu le-yl le-aldehyde noma i-ketone liyaba yi-protonated, okwenza libe yi-electrophilic kakhulu. Ngemuva kwalokho, i-ammonia ihlasela i-carbonyl carbon eba yi-protonated, ilandelwe yi-deprotonation ukuze yakhe i-imine.

2. Okulandelayo, i-cyanide ion (CN⁻) evela ku-sodium cyanide isebenza njenge-nucleophile futhi ihlasela i-imine carbon. Lokhu kwakha i-α - amino nitrile ephakathi.

3. Ekugcineni, i-hydrolysis ye-α - amino nitrile ngaphansi kwezimo ezine-acidic noma eziyisisekelo ikhiqiza i-α - amino acid ehambisanayo.

Ukusabela kwe-Strecker kunikeza indlela eqondile yokwethula kokubili iqembu le-amino neqembu le-carboxyl (ngemuva kwe-hydrolysis ye-nitrile) ku-athomu yekhabhoni eyodwa, ebalulekile ekuhlanganiseni kwama-amino acid, amabhlogo wokwakha amaprotheni. Isibonelo, lapho i-formaldehyde (HCHO) isabela nge-ammonium chloride ne-sodium cyanide, ilandelwa i-hydrolysis, i-glycine (NH₂CH₂COOH), i-amino acid elula, ingatholakala.

Ukulungiswa kwamaNitriles

I-sodium cyanide ivame ukusetshenziselwa ukulungisa ama-nitriles. Ekuphenduleni esikhundleni, i-alkyl halides (efana ne-methyl bromide, i-CH₃Br) isabela nge-sodium cyanide ku-solvent ye-aprotic emhlophe njenge-dimethyl sulfoxide (DMSO) noma i-acetone. Ukusabela kuqhubeka ngendlela ye-SN2, lapho i-cyanide ion ihlasela i-athomu yekhabhoni ehlanganiswe ne-halogen. I-athomu ye-halogen iyasuswa, futhi kwakhiwa i-alkyl nitrile. Ngokwesibonelo:

CH₃Br + NaCN → CH₃CN + NaBr

I-Aryl nitriles ingabuye ihlanganiswe kusetshenziswa i-sodium cyanide ezimweni ezithile. Isibonelo, kwezinye izinguquko - i-metal - catalyzed reactions, i-aryl halides ingasabela nge-sodium cyanide phambi kwe-catalyst efana ne-copper(I) cyanide (CuCN) noma i-palladium catalysts. Lokhu kusabela kuvumela ukwethulwa kweqembu elisebenzayo - CN eringini enamakha, ewusizo ekuhlanganiseni kwemithi ehlukahlukene, amakhemikhali ezolimo, kanye nodayi.

I-Benzoin Condensation

I-benzoin condensation ingenye ukusabela okubalulekile lapho i-sodium cyanide idlala indima ebalulekile. Kule ndlela yokusabela, ama-aldehyde anephunga elimnandi (ama-aldehyde anendandatho enamakha, njenge-benzaldehyde, C₆H₅CHO) asabela lapho kukhona inani le-catalytic le-sodium cyanide esixazululweni sotshwala. Indlela yokusabela ihlanganisa lezi zinyathelo ezilandelayo:

1. I-cyanide ion iqala yengeza ku-carbonyl carbon ye-benzaldehyde, esebenza njenge-nucleophile. Lo mkhiqizo wokwengeza uyi-cyanohydrin - efana nendawo ephakathi.

2. Ukushajwa okungekuhle ku-athomu yomoya-mpilo ye-cyanohydrin - njengokuphakathi kungase kuhlasele ikhabhoni ye-carbonyl yenye i-molecule ye-benzaldehyde.

3. Ngemuva kochungechunge lwezinyathelo zokudlulisa i-proton nokuqedwa kwe-ion ye-cyanide, i-benzoin (α - hydroxy - ketone) iyakhiwa.

I-benzoin condensation ihlinzeka ngendlela yokwakha isibopho esisha sekhabhoni - ikhabhoni phakathi kwama-molecule amabili e-aldehyde, abalulekile ekuhlanganiseni ama-molecule ezinto eziphilayo ayinkimbinkimbi. Nakuba eminyakeni yamuva nje, kuye kwenziwa imizamo yokushintsha i-sodium cyanide ngezisusa ezivumelana nemvelo ezifana nosawoti we-thiazolium noma uvithamini B₁, indlela evamile yokusebenzisa i-sodium cyanide isasebenza kwezinye izimo.

Ukusabela Okungeziwe Kumakhemikhali Angagcwalisiwe

I-sodium cyanide nayo ingabamba iqhaza ekuphenduleni okungeziwe kuma-unsaturated compounds. Isibonelo, lapho kukhona i-catalyst, ingeza ku-α,β - i-unsaturated carbonyl compounds (njenge-acrolein, CH₂=CHCHO). Ukusabela kulandela indlela yokwengeza yohlobo lwe-Michael, lapho i-ion ye-cyanide ihlasela i-β - carbon ye-α,β - i-unsaturated carbonyl compound. Lokhu kusabela kungasetshenziswa ukwethula iqembu le-cyanomethyl (-CH₂CN) ohlelweni olungenayo i-unsaturated, olungase luguqulwe lube amanye amaqembu asebenzayo. Isibonelo, umkhiqizo owumphumela ungafakwa nge-hydrolyzed ukuze wenze i-carboxylic acid noma uncishiswe ukuze wenze i-amine.

Ukucatshangelwa Kwezokuphepha

Njengoba kushiwo ngaphambili, i-sodium cyanide inobuthi kakhulu. Ukuhogela, ukumunca, noma ukuthinta isikhumba ne-sodium cyanide kungabulala. Ihlangana nama-asidi ukukhiqiza i-hydrogen cyanide (HCN), igesi enobuthi obuphezulu. Lapho uphatha i-sodium cyanide, lezi zinyathelo zokuphepha ezilandelayo kufanele zilandelwe ngokuqinile:

1. Sebenzisa endaweni enomoya omuhle ukuze uvimbele ukunqwabelana kwamagesi anobuthi.

2. Gqoka izinto zokuzivikela ezifanele, okuhlanganisa amagilavu, izibuko, nejazi laselabhu. Kwezinye izimo, kungase kudingeke umshini wokuphefumula.

3. Gcina i-sodium cyanide esitsheni esivikelekile, esinelebula kude nama-acids namanye amakhemikhali asebenzayo.

4. Yiba nezinhlelo ezifanele zokubhekana nezimo eziphuthumayo kanye namathuluzi endaweni lapho kuchitheka khona noma kuba nezingozi.

Isiphetho

I-sodium cyanide iyi-reagent eguquguqukayo futhi ebalulekile ku-organic synthesis. Ivumela ukwakheka kwamaqembu ahlukahlukene abalulekile asebenzayo njengama-amino acid, ama-nitriles, kanye ne-α - hydroxy - ketones, futhi ibamba iqhaza ekuphenduleni okubalulekile kwe-carbon - carbon bond - ukwakha ukusabela. Naphezu kobuthi bayo, lapho iphathwa ngokunakekelwa okwedlulele futhi ngokuhambisana nemithetho yezokuphepha, iyaqhubeka nokuba yithuluzi elibalulekile kukhithi yamathuluzi ye-synthetic chemist ekulungiseni inhlobonhlobo yezinhlanganisela eziphilayo, kusukela kwezokwelapha kuya kumakhemikhali amahle. Nokho, imizamo yocwaningo eqhubekayo igxile ekuthuthukiseni ezinye izindlela, izindlela eziphephile zokufeza izinhloso ezifanayo zokwenziwa.