Catalytic izibonelo ukuphendula. catalysis eyohlobo futhi heterogeneous

Chemistry - isayensi izinto futhi kugucuka zabo, kanye nezinqubo sokulungiselela yabo. Ngisho e uhlelo esikoleni njalo ubhekwa inkinga ebalulekile, zombili izinhlobo ukusabela. Ukwahlukanisa, ngawo abafundi baziswa ezingeni eliyisisekelo, uyakucabangela ukushintsha kwezinkathi namachibi isigaba ukugeleza, ngakho inqubo yokubuyisela. D. Ngaphezu kwalokho, zonke izinqubo zamakhemikhali zihlukaniswe ukusabela okhanda amanye amathuba kanye non-okhanda amanye amathuba. Izibonelo kugucuka ezenzeka nge ekwandeni ihlangabezana indoda ekuphileni kwansuku zonke: ukuvutshelwa, elibi. ukuguqulwa Non-okhanda amanye amathuba, thina zivamile ingasaphathwa.

Kuyini kulethe

Lokhu zamakhemikhali, okuyinto akwazi ukushintsha izinga ukusabela, kodwa uqobo ke azisetshenziswa. Esimweni lapho ekwandeni senzeka nge inqubo ukushesha, likhuluma catalysis omuhle. Kuleso simo, uma ejenti kungezwe inqubo kunciphisa izinga yokusabela, ubizwa ngokuthi inhibitor.

izinhlobo catalysis

catalysis eyohlobo futhi heterogeneous kuhluke isigaba, lapho kukhona ukuqala izinto. Uma izingxenye kokuqala, ayiswe ekuhlanganyeleni, kuhlanganise kulethe, kukhona esimweni esifanayo aggregate, ugeleza catalysis eyohlobo. Esimweni lapho ukusabela is ubuhanjelwe isigaba ezahlukene ndaba, kuyinto catalysis heterogeneous.

I selectivity isenzo

Catalysis akuyona nje indlela ukuthuthukisa ukusebenza ngcono imishini, it has a nethonya elihle izinga lemikhiqizo. Isenzakalo esifanayo zingachazwa ngezinqubo yokuthi ngenxa abakhethayo (abakhethayo) isenzo catalysts kakhulu yanda yi oqondile ukuphendula encishisiwe ohlangothini izinqubo. Ekugcineni, imikhiqizo etholakale abe msulwa ephakeme Akubalulekile eminye nihlanze ketshezi. I selectivity zezenzakalo ekwandeni unika ukunciphisa ngempumelelo izindleko ze-non-elikhiqizayo of izinto zokusetshenziswa, izinzuzo ezinhle kwezomnotho.

Izinzuzo isicelo emsebenzini wokukhiqiza ekwandeni

Yini enye zinezikhathi ukusabela okhanda amanye amathuba? Izibonelo njengesono ezivamile esikoleni esiphakeme, abonisa ukuthi ukusetshenziswa kulethe ivumela inqubo at okushisa aphansi. Ukuhlolwa abonisa ukuthi ingasetshenziswa ukubala ukuncipha eziphawulekayo izindleko energy. Lokhu kubalulekile ikakhulukazi kwezimo zamanje, uma kukhona nokushoda kwezidingongqangi amandla emhlabeni.

Izibonelo okhanda amanye amathuba silwenza

Yikuphi umkhakha zisebenzisa ukusabela okhanda amanye amathuba? Izibonelo izitshalo ezifana: ukukhiqizwa nitric futhi acid sulfuric, i-hydrogen, i-ammonia, polymers kanye ukucutshungulwa uwoyela. Kabanzi catalysis ekulungiseleleni acid organic, monohydric kanye alcohols polyhydric, phenol inhlaka, udayi, nemithi.

Uyini kulethe

I yelikhono ongakhonza izinto eziningi ekhona ohlelweni zesikhathi izakhi zamakhemikhali Dmitriya Ivanovicha Mendeleeva, futhi compounds zabo. Phakathi accelerators ezivamile ahlukanisa-nickel, i-iron, i-platinum, ayibe, alumosilicates, manganese oxides.

Izici ekwenyuseni

Ngaphezu abakhethayo isinyathelo yelikhono babe kakhulu amandla mechanical, ingakwazi ukumelana ubuthi okhanda amanye amathuba, ezivuselela kalula (abuyiselwe).

Sigaba okhanda amanye amathuba ukusabela eyohlobo zihlukaniswe igesi isigaba kanye isigaba liquid.

Ukuhlolisisa lezo zinhlobo ukusabela. Ngo izixazululo yamakhemikhali ukuguqulwa namafutha aphume ashone hydrogen cations H +, base hydroxide ion OH-, metal cations, M +, futhi izinto okuyinto ukukhuthaza ukwakheka radicals khulula.

Ingqikithi catalysis

Mechanism Catalysis by ukusabela acid lezisekelo wukuthi kukhona exchange phakathi izinto uxhumana futhi kulethe ion omuhle (proton). Ngakho kugucuka intramolecular zenzeke. Ukuze le ndlela yokusabela yilezi:

• amanzi emzimbeni (amanzi uncoupling);
• hydration (okunamathiselwe zishintshe amanzi);
• esterification (kumiswa ester kusukela alcohols futhi acid carboxylic);
• polycondensation (polymer ukwakheka nge cleavage ngamanzi).

Imfundiso yokuziphendukela catalysis uchaza hhayi kuphela inqubo kodwa futhi kungenzeka ohlangothini ukuguqulwa. Uma othile heterogeneous catalysis inqubo yakha ahlukene isigaba namafutha, babe ezinye izakhiwo okhanda amanye amathuba ngamaphuzu kobuso reactants noma bonke ubuso ehilelekile.

Kunendlela microheterogeneous okubandakanya ekutholeni kulethe esimweni colloidal. Lokhu kukhetha isimo zesikhashana kusukela eyohlobo ukuba heterogeneous catalysis engqondweni. Eziningi zalezi izinqubo kwenzeka phakathi izinto gaseous usebenzisa yelikhono okuqinile. Kungenzeka ngesimo zithutha, amaphilisi, okusanhlamvu.

Ukusatshalaliswa catalysis ngokwemvelo

catalysis enzyme zisakazwa nemvelo. It wabe nge biocatalysts zamagama wamaprotheni amangqamuzana, umzimba kwenziwa ezintweni eziphilayo. Akekho izinqubo yezinto eziphilayo ezihilela izinto eziphilayo, abazigwemi ukusabela okhanda amanye amathuba. Izibonelo izinqubo ezibalulekile: zamagama amino acid esuka amaprotheni ethize umzimba; ukuwohloka kwamafutha, amaprotheni, ama-carbohydrate.

catalysis algorithm

Cabanga indlela ye-catalysis. Le nqubo ezenzeka ukungena nakwamanye amazwe accelerators okuqinile chemical nokuxhumana, sifaka izinyathelo eziyisisekelo ezimbalwa:

• okusheshayo we reactants ebusweni nangangesihlabathi kulethe kusukela umfudlana ikhenela;
• nokuhanjiswa kwe- reactants ku ezimbotsheni kulethe;
• chemisorption (adsorption isebenze) phezu namafutha chemical ukusabela leholele surface ikhemikhali - izakhiwo isebenze "kulethe reagents";
• rearrangement zama-athomu ne nesenzakalo surface inhlanganisela "kulethe-umkhiqizo";
• okusheshayo e ezimbotsheni namafutha komkhiqizo ukuphendula;
• umkhiqizo okusheshayo ebusweni ukugeleza kokusanhlamvu core ukuphendula namafutha.

ukusabela okhanda amanye amathuba kanye non-okhanda amanye amathuba zibaluleke kakhulu kangangokuthi ososayensi eminyakeni uqhubeke nocwaningo kule ndawo.

Lapho catalysis eyohlobo asikho isidingo ukwakha imiklamo ekhethekile. catalysis enzyme okufana heterogeneous kuhilela ukusetshenziswa imishini ahlukahlukene futhi eziqondile. Ukuze flow yayo athuthukile amadivayisi ezikhethekile contact, selihlukene ebusweni contact (e-amashubhu, ezindongeni ekwandeni meshes); a sesimbozo; slurry embhedeni; ziyacolwa nge kulethe ezihambayo.

ukudluliselwa Heat e apharathasi luyasetshenziswa ngetindlela letehlukene:

• ngokusebenzisa akude (zangaphandle) ukushisa;
• nge ukushisa, ezishumekwe apharathasi contact.

Ukuhlaziya ifomula yokuthakwa kwamakhemikhali, kungatholakala ukusabela okunjalo lapho kulethe uba omunye imikhiqizo yokugcina, imiswe phakathi neminyaka nokuxhumana chemical yezingxenye kokuqala okuyinto.

izinqubo maKristu abizwa autocatalytic, lomkhuba kwamakhemikhali ngokuthi autocatalysis.

Speed ekusebenzisaneni eziningi ngenxa yokuba khona e ingxube ukusabela izinto ezithile. amafomula abo-chemistry ivame ukunganakwa, esikhundleni igama elithi "kulethe" noma isifinyezo yayo kule. Abanaso zihlanganisa stereochemistry yokugcina equation, ngoba, emva kokuphothulwa ukuphendula ayishintshi kusukela iphuzu ambalwa of umbono. Kwezinye izimo, ngokwanele nengcosana izinto kakhulu ezithinta ngesilinganiso eqhubekayo. Kuvumeleke nezimo njengalapho namafutha chemical nokuxhumana ngokwayo izenzo ukuphendula isitsha.

Ingqikithi ithonya kulethe ushintsho ngesilinganiso iyinkimbinkimbi inqubo yamakhemikhali ukuthi imfuyo likhona yokwakheka eziyinkimbinkimbi asebenzayo, futhi ngenxa yalokho kushintsha amandla ukusebenza nokuxhumana zamakhemikhali.

Ngo ukubola eziyinkimbinkimbi kulethe ukuvuselelwa siyenzeka. Iphuzu eliyinhloko ukuthi ngeke sisetshenziswe, izohlala ingashintshiwe ngemva inani ukuxhumana. Kungenxa yalesi sizathu kuyinto ubuningi ngokwanele elincane ketshezi asebenzayo ukuxubana substrate (ukuphendula reagent). Eqinisweni, inani kancane kulethe e yezinqubo zamakhemikhali nokho kudliwe, njengoba kungase kube izinqubo ezihlukahlukene yesibili: ke ushevu inqubo ukulahlekelwa, ushintsho isimo kobuso kulethe okuqinile. Formula yokuthakwa kwamakhemikhali azihileli accounting kulethe.

isiphetho

Ukuphendula, okwakuhilela isithako esebenzayo (kulethe) azungeze umuntu, ngaphandle kokuba egeleza umzimba wayo. ukusabela eyohlobo kukhona ingasaphathwa ezivamile kuka nokuxhumana heterogeneous. Kunoma ikuphi, kuqala ukwakheka izakhiwo Lesisemkhatsini, okuyizinto engazinzile, kancane kancane aphambane phansi khona ukuvuselelwa (sokubuyiselwa) ka namafutha we inqubo yamakhemikhali. Ngokwesibonelo, nokuxhumana metaphosphoric acid potassium persulfate njengoba kulethe izenzo hydriodic acid. Lapho ukungezwa ku reactants kwakhiwa isixazululo ophuzi. Njengoba sisondela ekupheleni luphola inqubo coloration. Njengoba umkhiqizo Lesisemkhatsini kulokhu iodine, futhi inqubo senzeka ngezigaba ezimbili. Kodwa kulethe kanye metaphosphoric acid is kuhlelwe umqondo ebuyiselwa esimeni sayo esingu ngqo. Catalysts azinakusilela umkhakha, zisiza zokusheshisa uguquko ukuthola imikhiqizo ephezulu ukuthi bayavuma. Akunakwenzeka ngaphandle iqhaza zabo futhi izinqubo kwamakhemikhali emzimbeni.