Cov tshuaj thaj chaw ntawm aldehydes: cov tshuaj tiv thaiv ntawm cov nyiaj daim iav

Aldehydes yog haumxeeb derivatives ntawm hydrocarbons, nyob rau hauv uas cov qauv muaj ib pab pawg neeg CO (carbonyl pab pawg neeg). Rau tej yam yooj yim aldehydes tsis tseem ceeb feeb cia (historic) npe, tsim los ntawm cov npe ntawm carboxylic acids, uas yog hloov dua siab tshiab rau hauv aldehydes los ntawm oxidation. Yog hais tias peb tham txog cov IUPAC nomenclature, lub hauv paus rau kev noj lub coos saw uas muaj cov aldehyde pab pawg neeg. Pib numbering hydrocarbon saw tsim los ntawm cov pa roj carbon atom ntawm lub carbonyl pab pawg neeg (CO), uas nws tus kheej tau txais ib tug title tooj 1. lub ntsiab hydrocarbon saw ntxiv mus rau thaum xaus ntawm "al". Txij li thaum aldegidogruppa nyob rau ntawm lub saw kawg, tus tus nab npawj 1, yog feem ntau tsis sau. Isomerism isomerism rau tam sim no tebchaw yog vim muaj ib tug hydrocarbon cev pob txha.

Lub aldehydes tau nyob rau hauv ob peb txoj kev: oxo txheej txheem, alkynes co, oxidation thiab dehydrogenation ntawm alcohols. Kev npaj ntawm aldehydes los ntawm thawj alcohols yuav tsum tau tshwj xeeb tej yam kev mob, txij thaum lub generated organic tebchaw nkag oxidized rau carboxylic acid. Aldehydes kuj yuav tsim los ntawm dehydrating lub sib nug xov alcohols nyob rau hauv lub xub ntiag ntawm tooj liab. Ib tug loj industrial txoj kev ua aldehydes yog cov tshuaj tiv thaiv ntawm lub oxo synthesis, uas yog raws li nyob rau hauv cov tshuaj tiv thaiv ntawm ib tug alkene, C0 thiab H2 nyob rau hauv lub xub ntiag ntawm catalysts muaj Co, nyob ib tug kub ntawm 200 degrees thiab ib tug siab ntawm 20 MPa. Qhov no cov tshuaj tiv thaiv tau nyaij nyob rau hauv cov kua los yog nyob rau hauv cov roj theem raws li lub tswvyim: RCH = CH2 + C0 + H2 - RCH2CH2C0H + RCH (CH) 3C0H. Aldehydes yuav tsum npaj kom txhij los ntawm hydrolysis digalogenoproizvodnyh hydrocarbons. Thaum lub sij hawm cov kev hloov ntawm lub halogen atoms nyob rau OH neeg ntawm cov intermediate yog tsim thiaj li hu ua heme-diol, uas yog tsis ruaj tsis khov thiab yog hloov dua siab tshiab nyob rau hauv lub carboxylic compound nrog tshem tawm ntawm H20.

Cov tshuaj cov khoom teejtug uas aldehydes - ib tug zoo lus teb rau nyiaj. Thaum lub sij hawm oxidation lub aldehydes yog hloov dua siab tshiab rau carboxylic acid (e.g., S5N11SON + O - S5N11SOON). Nyob rau hauv txhua nplooj siab phau ntawv yuav nrhiav tau cov lus qhia hais txog dab tsi cov nyiaj daim iav cov tshuaj tiv thaiv no yog siv rau cov cim ntawm aldehydes. Qhov no pab pawg neeg ntawm cov organic tebchaw yuav oxidized tsis tau tsuas yog los ntawm qhov kev txiav txim tshwj xeeb oxidizing agents, tab sis tsuas yog thaum lub sij hawm cia nyob rau hauv tus ntawm huab cua oxygen. Cov yooj yim uas cov aldehydes oxidised rau carboxylic acid tso cai los tsim zoo tshua (silver daim iav cov tshuaj tiv thaiv) rau cov organic tebchaw, uas ua rau nws tau kom sai thiab kom meej meej qhia hais tias tus xub ntiag ntawm aldehyde nyob rau hauv ib tug muab tshuaj.

Thaum rhuab nrog ib tug ammoniacal tshuaj ntawm nyiaj oxide rau lub acid aldehyde yog oxidized. Thaum zoo li no yog txo mus rau nws yog xim hlau nyiaj thiab yog tso rau hauv lub raj phab ntsa raws li ib tug maub txheej nrog ib tug yam ntxwv gloss - nyiaj daim iav cov tshuaj tiv thaiv. Nws yuav tsum tau muab sau tseg hais tias muaj ntau ntau yam tshuaj uas tsis muaj feem xyuam rau aldehydes, tab sis lawv kuj muaj peev xwm nkag mus kawm rau hauv lub saum toj no cov tshuaj tiv thaiv. Rau cov cim ntawm cov tebchaw siv yog ib qhov zoo tshuaj tiv thaiv rau aldehydes - tooj liab daim iav cov tshuaj tiv thaiv. Nyob rau hauv cov tshuaj tiv thaiv ntawm aldehydes nrog Fehling reagent muaj ib tug xiav xim (ib tug aqueous tov ntawm cupric hydroxide, ib tug alkali thiab acid tartrate ntsev) ntawm divalent tooj liab yog txo mus rau monovalent. Yog li ntog liab-xim av precipitate ntawm cuprous oxide.

Yog li ntawd, yuav ua li cas nws yog nqa tawm cov tshuaj tiv thaiv ntawm cov nyiaj daim iav? Nws yuav zoo li uas tsis muaj dab tsi yooj yim sov li sufficiently nyob rau hauv ib lub lauj kaub ammoniacal tshuaj ntawm nyiaj nrog ib yam ntawm cov aldehydes (e.g., ib tug zib tov los yog formaldehyde) tab sis qhov no mus kom ze yog tsis ib txwm crowned yeej. Tej zaum peb soj ntsuam cov tsim ntawm ib tug dub ncua kev kawm ntawv ntawm cov nyiaj nyob rau hauv cov tshuaj, es tsis txhob ntawm daim iav txheej ntawm cov phab ntsa hauv lub khob iav. Yuav ua li cas yog lub ntsiab yog vim li cas rau tsis ua hauj lwm? 100% tshwm sim nws yog tsim nyog los ua raws li cov tshuaj tiv thaiv tej yam kev mob, thiab ua tib zoo npaj lub iav nto.