Chemistry yog kev tshawb fawb ntawm cov tshuaj thiab lawv cov kev hloov pauv, nrog rau cov txheej txheem kom tau txais lawv. Txawm tias nyob rau hauv ib lub tsev kawm ntawv cov ntaub ntawv kawm, xws li ib tug tseem ceeb qhov teeb meem raws li hom kev tawm tsam yog xam. Kev faib tawm uas cov menyuam kawm ntawv tau nkag mus rau hauv cov theem pib yuav tsum tau coj mus rau hauv tus account qhov kev hloov ntawm cov degree ntawm oxidation, theem ntawm cov chav kawm, lub mechanism ntawm tus txheej txheem, thiab lwm yam. Tsis tas li ntawd, tag nrho cov txheej txheem tshuaj yog muab faib ua non-catalytic thiab catalytic. cov tshuaj tiv thaiv. Piv txwv ntawm kev hloov pauv tshwm sim nrog kev koom tes ntawm cov catalyst tau ntsib los ntawm ib tus neeg hauv lub neej zoo tib yam: fermentation, lwj. Kev hloov pauv tsis-catalytic yog qhov tsawg dua rau peb.
Dab tsi yog catalyst
Nov yog ib yam tshuaj uas tuaj yeem hloov pauv kev sib cuam tshuam, tab sis tsis koom nrog nws tus kheej. Nyob rau hauv rooj plaub thaum tus txheej txheem yog ceev nrog kev pab los ntawm ib tug catalyst, peb tab tom tham txog zoo catalysis. Nyob rau hauv cov xwm txheej uas ib yam khoom ntxiv rau tus txheej txheem txo tus nqi ntawm cov tshuaj tiv thaiv, nws yog hu ua inhibitor.
Type of catalysis
Homogeneous thiab heterogeneous catalysis sib txawv hauv theem, hauvuas cov ntaub ntawv pib nyob. Yog hais tias thawj cov khoom siv rau kev sib cuam tshuam, suav nrog cov catalyst, nyob rau hauv tib lub xeev ntawm kev sib sau ua ke, homogeneous catalysis ua tiav. Nyob rau hauv rooj plaub thaum cov tshuaj ntawm cov theem sib txawv koom nrog cov tshuaj tiv thaiv, heterogeneous catalysis tshwm sim.
Kev xaiv ntawm kev nqis tes ua
Catalysis tsis yog ib qho kev nce qib ntawm cov khoom siv, nws muaj txiaj ntsig zoo rau qhov zoo ntawm cov khoom tsim tawm. Qhov tshwm sim no tuaj yeem piav qhia los ntawm qhov tseeb tias vim yog kev xaiv (xaiv) kev ua ntawm feem ntau cov catalysts, cov tshuaj tiv thaiv ncaj qha tau nrawm, cov txheej txheem sab nraud raug txo. Thaum kawg, cov khoom ua tau zoo yog cov purity siab, tsis tas yuav ua kom huv ntxiv rau cov tshuaj. Qhov kev xaiv ntawm qhov kev txiav txim catalyst muab qhov txo qis ntawm cov nqi tsis tsim khoom ntawm cov khoom siv raw, qhov txiaj ntsig zoo nyiaj txiag.
txiaj ntsig ntawm kev siv lub catalyst hauv kev tsim khoom
Dab tsi ntxiv tus yam ntxwv ntawm cov tshuaj tiv thaiv catalytic? Piv txwv los ntawm ib lub tsev kawm ntawv theem siab qhia tau hais tias kev siv cov catalyst tso cai rau cov txheej txheem ua haujlwm ntawm qhov kub thiab txias. Cov kev sim paub meej tias nws tuaj yeem siv los txo cov nqi hluav taws xob ntau. Qhov no yog qhov tseem ceeb tshwj xeeb tshaj yog nyob rau niaj hnub no, thaum tsis muaj kev siv hluav taws xob hauv ntiaj teb.
Examples of catalytic production
Kev lag luam twg siv cov tshuaj tiv thaiv catalytic? Piv txwv ntawm xws li productions:kev tsim cov nitric thiab sulfuric acids, hydrogen, ammonia, polymers, roj refining. Catalysis yog siv dav hauv kev tsim cov organic acids, monohydric thiab polyhydric alcohols, phenol, hluavtaws resins, dyes, thiab tshuaj.
Dab tsi yog qhov catalyst
Ntau yam khoom uas muaj nyob rau hauv lub sij hawm ntawm cov tshuaj ntawm Dmitry Ivanovich Mendeleev, nrog rau lawv cov tebchaw, tuaj yeem ua raws li catalysts. Ntawm cov accelerators feem ntau yog: npib tsib xee, hlau, platinum, cob alt, aluminosilicates, manganese oxides.
Txhim kho cov catalysts
Ntxiv rau qhov kev txiav txim siab, cov catalysts muaj lub zog zoo heev, lawv muaj peev xwm tiv taus cov tshuaj lom catalytic, thiab yooj yim rov tsim dua tshiab (rov qab).
Raws li lub xeev theem, cov tshuaj tiv thaiv catalytic homogeneous tau muab faib ua roj-theem thiab kua-theem.
Cia peb saib ze dua ntawm cov kev tawm tsam no. Hauv kev daws teeb meem, hydrogen cations H +, hydroxide hauv paus ions OH-, hlau cations M + thiab cov khoom uas pab tsim cov dawb radicals ua tus tsuj roj hloov pauv.
Lub ntsiab ntawm catalysis
Lub tshuab ntawm catalysis hauv kev sib cuam tshuam ntawm cov kua qaub thiab cov hauv paus yog tias muaj kev sib pauv ntawm cov khoom sib cuam tshuam thiab cov catalyst zoo ions (protons). Hauv qhov no, kev hloov pauv intramolecular tshwm sim. Raws li qhov noCov tshuaj tiv thaiv zoo li no:
- dehydration (dej detachment);
- hydration (txuas ntawm cov dej molecules);
- esterification (ester tsim los ntawm cawv thiab carboxylic acids);
- polycondensation (tsim ntawm cov polymer nrog tshem tawm dej).
Txoj kev xav ntawm catalysis piav tsis yog cov txheej txheem nws tus kheej xwb, tab sis kuj tuaj yeem hloov pauv sab nraud. Nyob rau hauv cov ntaub ntawv ntawm heterogeneous catalysis, lub accelerator ntawm cov txheej txheem tsim ib tug ywj siab theem, ib co chaw nyob rau saum npoo ntawm cov reactants muaj catalytic zog, los yog tag nrho cov nto yog koom tes.
Tseem kuj tseem muaj cov txheej txheem microheterogeneous, uas cuam tshuam nrog kev muaj cov catalyst hauv lub xeev colloidal. Qhov kev hloov pauv no yog lub xeev hloov pauv los ntawm homogeneous mus rau heterogeneous hom catalysis. Feem ntau ntawm cov txheej txheem no tshwm sim ntawm cov tshuaj gaseous siv cov khoom catalysts. Lawv tuaj yeem ua cov granules, ntsiav tshuaj, nplej.
Kev faib cov catalysis hauv xwm
Enzymatic catalysis yog dav dav hauv qhov xwm txheej. Nws yog nrog kev pab los ntawm biocatalysts uas cov synthesis ntawm cov protein molecules tshwm sim, cov metabolism hauv cov kab mob muaj sia yog nqa tawm. Tsis yog ib txoj kev lom neeg uas tshwm sim nrog kev koom tes ntawm cov kab mob muaj sia hla dhau cov tshuaj tiv thaiv catalytic. Piv txwv ntawm cov txheej txheem tseem ceeb: synthesis ntawm cov proteins tshwj xeeb rau lub cev los ntawm cov amino acids; Kev rhuav tshem cov rog, cov protein, carbohydrates.
Catalysis algorithm
Cia peb xav txog cov txheej txheem ntawm catalysis. Cov txheej txheem no, uas yuav siv qhov chaw ntawm cov khoom siv tshuaj lom neeg sib cuam tshuam accelerators, suav nrogkoj tus kheej ob peb theem pib:
- diffusion ntawm interacting tshuaj mus rau saum npoo ntawm catalyst nplej los ntawm cov tub ntxhais ntawm cov ntws;
- diffusion ntawm reagents nyob rau hauv pores ntawm lub catalyst;
- chemisorption (activated adsorption) rau ntawm qhov chaw ntawm cov tshuaj tiv thaiv tsuj roj nrog cov tsos ntawm cov tshuaj lom neeg - activated catalyst-reagent complexes;
- rov kho ntawm atoms nrog cov tsos ntawm cov khoom sib txuas "catalyst-cov khoom";
- diffusion hauv qhov pores ntawm cov khoom lag luam tshuaj tiv thaiv accelerator;
- diffusion ntawm cov khoom los ntawm cov nplej saum npoo ntawm cov tshuaj tiv thaiv accelerator rau hauv cov tub ntxhais ntws.
Catalytic thiab non-catalytic cov tshuaj tiv thaiv tseem ceeb heev uas cov kws tshawb fawb tau txuas ntxiv tshawb fawb hauv cheeb tsam no tau ntau xyoo.
Nrog homogeneous catalysis, tsis tas yuav tsim cov qauv tshwj xeeb. Enzymatic catalysis nyob rau hauv heterogeneous version muaj kev siv ntau yam thiab cov cuab yeej tshwj xeeb. Rau nws cov ndlwg, tshwj xeeb kev sib cuag apparatuses tau tsim, subdivided raws li kev sib cuag nto (hauv hlab, ntawm phab ntsa, catalyst daim phiaj); nrog ib txheej lim; hnyav txheej; nrog txav pulverized catalyst.
Kev sib pauv cua sov hauv cov khoom siv tau siv ntau txoj hauv kev:
- dhau los ntawm kev siv cov chaw taws teeb (sab nraud) cov cua sov hloov pauv;
- nrog kev pab ntawm cov khoom siv hluav taws xob ua rau hauv lub tshuab tiv tauj.
Los ntawm kev tshuaj xyuas cov qauv hauv chemistry, ib tus tuaj yeem pom cov tshuaj tiv thaiv uas cov catalyst yog ib qho ntawm cov khoom kawg uas tau tsim thaum lub sij hawm tshuaj sib cuam tshuam.cov khoom qub.
Cov txheej txheem zoo li no feem ntau hu ua autocatalytic, qhov tshwm sim nws tus kheej hu ua autocatalysis hauv chemistry.
Tus nqi ntawm ntau qhov kev sib cuam tshuam yog txuam nrog muaj qee yam khoom hauv cov tshuaj tiv thaiv sib tov. Lawv cov qauv hauv chemistry feem ntau tsis nco qab, hloov los ntawm lo lus "catalyst" lossis nws cov ntawv luv luv. Lawv tsis suav nrog qhov kawg ntawm kev sib npaug stereochemical, txij li lawv tsis hloov los ntawm qhov pom ntawm qhov ntau tom qab ua tiav ntawm kev sib cuam tshuam. Qee qhov xwm txheej, cov khoom me me yog txaus los cuam tshuam rau kev ceev ntawm cov txheej txheem. Cov xwm txheej kuj tau txais txiaj ntsig zoo thaum cov tshuaj tiv thaiv hlab ntsha nws tus kheej ua raws li kev sib txuas tshuaj lom neeg.
Lub ntsiab lus ntawm cov nyhuv ntawm cov catalyst ntawm kev hloov pauv tus nqi ntawm cov txheej txheem tshuaj yog tias cov tshuaj no suav nrog hauv cov muaj pes tsawg leeg ntawm cov nquag ua haujlwm, thiab yog li hloov lub zog ua kom muaj zog ntawm kev sib cuam tshuam tshuaj.
Thaum lub complex decomposes, lub catalyst yog regenerated. Cov kab hauv qab yog tias nws yuav tsis siv, nws yuav nyob twj ywm hauv tib tus nqi tom qab qhov kawg ntawm kev sib cuam tshuam. Nws yog vim li no tias ib qho me me ntawm cov tshuaj nquag muaj txaus los ua cov tshuaj tiv thaiv nrog cov substrate (reacting substance). Nyob rau hauv kev muaj tiag, tsis tseem ceeb npaum li cas ntawm catalysts yog tseem noj thaum lub sij hawm cov txheej txheem tshuaj, txij li thaum muaj ntau yam sab txheej txheem yog ua tau: nws lom, technology poob, thiab ib tug hloov nyob rau hauv lub xeev ntawm lub nto ntawm ib tug khoom catalyst. Chemistry formulas tsis suav nrog cov catalyst.
Zoo kawg
Cov tshuaj tiv thaiv uas muaj cov tshuaj nquag (catalyst) koom nrog ib puag ncig tus neeg, dhau li ntawd, lawv kuj tshwm sim hauv nws lub cev. Homogeneous cov tshuaj tiv thaiv tsis tshua muaj ntau dua li kev sib cuam tshuam heterogeneous. Nyob rau hauv txhua rooj plaub, intermediate complexes yog thawj tsim, uas yog tsis ruaj tsis khov, yog maj mam rhuav tshem, thiab regeneration (rov qab) ntawm lub accelerator ntawm cov tshuaj yog soj ntsuam. Piv txwv li, thaum metaphosphoric acid reacts nrog poov tshuaj persulfate, hydroiodic acid ua raws li catalyst. Thaum nws ntxiv rau cov reactants, cov tshuaj daj yog tsim. Thaum koj mus txog qhov kawg ntawm cov txheej txheem, cov xim maj mam ploj mus. Hauv qhov no, iodine ua raws li cov khoom nruab nrab, thiab cov txheej txheem tshwm sim hauv ob theem. Tab sis sai li sai tau thaum metaphosphoric acid yog synthesized, lub catalyst rov qab mus rau nws cov qub xeev. Catalysts yog qhov tseem ceeb hauv kev lag luam, lawv pab ua kom muaj kev hloov pauv sai thiab tau txais cov khoom lag luam zoo. Cov txheej txheem biochemical hauv peb lub cev kuj ua tsis tau yam tsis muaj kev koom tes.
