Rule Markovnikova V. V. Essence nezibonelo

Ekuphenduleni kwamakhemikhali endaweni yokubhujiswa kwesibopho kabili kuma-alkenes futhi kathathu kuma-alkynes, izinhlayiya ezihlukahlukene zingahlanganiswa. Yimiphi imithetho yale nqubo? Ukuziphatha kwama-homologue asymmetric e-ethylene phakathi ne-hydrohalogenation kanye ne-hydration yafundiswa isosayensi waseRussia uVV Markovnikov. Wathola ukuthi indlela yokusabela ngayo incike ekutheni i-hydrogen engakanani iboshelwe ku-carbon ngokubambisana kabili. I-hypothesis eyathuthukiswa usosayensi yaqinisekiswa ngemva kokuthola emkhakheni wesakhiwo se-athomu. Umbuso waseMarkovnikov wabeka isisekelo sokwakhiwa kwengqikithi yesayense enesicelo esisebenzayo. Ivumela ukuhlelwa ngokweqile ukukhiqizwa kwe-polymers, izithako, utshwala.

Umthetho waseMarkovnikov

Usosayensi waseRussia wazinika isikhathi esiningi emsebenzini wakhe ekutadisheni indlela yokuhlanganisa ama-reagents asymmetric kuma-hydrocarboni angasetshenzisiwe. Esihlokweni sakhe esashicilelwe ngesiJalimane ngo-1870, i-VV Markovnikov yakhanga umphakathi wesayense ekukhethweni kokusebenzisana kwama-hydrogen halides ngama-athomu e-carbon atholakala kusibopho esiphindwe kabili kuma-alkenes angafani. Umcwaningi waseRussia ucacise idatha ayeyitholile emtholampilo ebhokisatri yakhe. UMarkovnikov wabhala ukuthi i-halogen ihlanganisa i-athomu ye-carbon, equkethe inani elincane lama-athomu e-hydrogen. Ukuthandwa kakhulu komsebenzi wasosayensi kwatholakala ekuqaleni kwekhulu lama-20. I-hypothesis yenqubo yokuxhumana ehlongozwa nguye ibizwa ngokuthi "uMbuso waseMarkovnikov".

Ukuphila nomsebenzi womsayense wezinto eziphilayo

UVladimir Vasil'evich Markovnikov wazalelwa ngoDisemba 25, 1837 (ngesitayela ngokusho kwesitayela saseSt. Petersburg). Wafunda eNyuvesi yaseKazan, kamuva wafundisa kule sikole naseMoscow University. UMarkovnikov wafunda ukuziphatha kwama-hydrocarboni angenayo i-unsaturated ekusebenzelaneni ne-hydrogen halides kusukela ngo-1864. Kuze kube ngu-1899, ososayensi abavela kwamanye amazwe abazange babambe iqhaza eziphethweni zamasosha aseRussia. UMarkovnikov, ngaphezu komthetho, ogama lakhe lihloniphekile, wenza ezinye izinto ezitholakalayo:

• I-cyclobutanedicarboxylic acid etholakele;
• Uhlolisise amafutha aseCaucasus futhi wathola kuwo izinto eziphilayo zokwakheka okhethekile - ama-naphthenes;
• Yakha umehluko emazingeni okushisa okuqhakazile okuhlanganiswa ngamaketanga e-branched ne-rectilinear;
• Kwafakazela ukuthi i-isomerism ye-fatty acids.

Imisebenzi yososayensi yakhiphe kakhulu ekuthuthukiseni isayensi yamakhemikhali asekhaya kanye nembonini.

Okuyisisekelo se-hypothesis esinikezwe uMarkovnikov

Usosayensi wazinika iminyaka eminingi ekutadisheni ukuphendula kokungeza kwama-hydroxyboni angasetshenzisiwe nge-bond eyodwa kabili (alkenes). Uphawula ukuthi uma i-hydrogen ikhona kulezi zinhlanganisela, iqondiswa kuleyo athomu ye-carbon, equkethe izinhlayiya eziningi zalolu hlobo. U-Anion ujoyina i-carbon eseduze. Lokhu kungukubusa kukaMarkovnikov, isisekelo sayo. Usosayensi wamemezela ngokucacile ukuziphatha kwezinhlayiya, okwakungakaze kube nemibono ecacile ngaleso sikhathi. Ngokuhambisana nomthetho, izinto eziyinkimbinkimbi ezinokubunjwa kwe-HX zengeziwe kuma-hydrocarbons e-ethylene, lapho i-X:

• I-Halogen;
• I-Hydroxyl;
• Ama-aseic acid ase-sulfuric acid;
• Ezinye izinhlayiya.

Ukumemeza kwamanje kombuso waseMarkovnikov kuhluke kokasosayensi: i-athomu ye-hydrogen ephuma kuyi-molecule ye-HX ehlanganiswe i-alkene iqondiswa kuleso sikhakha esivumelwaneni esiphindwe kabili esine-hydrogen engaphezulu, kanti i-particle X iqondiswa ku-athomu encane e-hydrogen.

Indlela yokunamathiswa kwezinhlayiya ze-electrophilic

Cabanga ngezinhlobo zokuguqulwa kwamakhemikhali lapho kusetshenziswa khona umthetho waseMarkovnikov. Izibonelo:

1. Ukusabela kokungeza ku-propene hydrogen chloride. Phakathi nokuxhumana phakathi kwezinhlayiyana, ukubopha kabili kubhujiswa. I-anion ye-chlorine iqondiswa engxenyeni encane ye-hydrogenated eyayisezibopho ezimbili. I-hydrogen ixhumana ne-hydrogenated kakhulu yalezi athomu. Amafomu e-2-chloro-propane.
2. Ekuphenduleni kokungeziwe kwe-molecule yamanzi, i-hydroxyl ekubunjweni kwayo ifaneleka kabhodini engaphansi kwe-hydrogenated. I-hydrogen ihlanganiswe ne-athomu engaphezu kwe-hydrogenated nge-bond bond kabili.

Kukhona okungafani nomthetho ohlongozwayo yiMarkovnikov kulawo aphendule lapho ama-alkenes enza khona njengama-reagents, lapho i-carbon in the bond kabili isivele inezinombolo zamaqembu okhetho. Ikhetha ngokwengxenye inani le-electron elihle kakhulu elikhokhiswa i-hydrogen ngokuvamile eliheha. Lo mthetho awubonakali ekuphenduleni okulandela okukhulu, hhayi umshini we-electrophilic (umphumela weHarish). Lezi zingaphandle azivimbeli ekufanelekeni kokubusa okuvela yi-Russian chemistry ephilayo evelele V. V. Markovnikov.