Aldehydes thiab ketones. Cov khoom thiab synthesis ntawm carbonyl tebchaw

Cov organic compound muaj nyob rau hauv nws cov molecular qauv ib carbonyl pab pawg neeg ntawm cov nram qab no daim ntawv:> C = O, - xa mus rau raws li oxo-tebchaw thiab yog muab faib ua ob sab - aldehydes thiab ketones. Raws li cov qauv ntawm hydrocarbon radicals, cov tshuaj yog txwv kom muab zais rau hauv aliphatic, uas muaj ntxhiab thiab alicyclic. Cov thawj thiab thib ob molecules yog yus muaj los ntawm ib tug carbonyl pab pawg neeg uas yog txuas ncaj qha mus rau ib tug benzene nplhaib los yog sab saw. Aldehydes thiab ketones nrog ib tug molecular daim ntawv cog lus ntawm cov uas muaj ntxhiab series, uas muaj ib tug functional ib pawg nyob rau hauv lub sab saw yog xam raws li derivatives ntawm aliphatic carbonyl tebchaw.

Aromatic aldehydes yog tsim nyob rau hauv ob lub ntsiab txoj kev: los ntawm qhia ib carbonyl pab pawg neeg mus rau ib tug benzene nplhaib nyob rau hauv electrophilic hloov thiab hloov dua siab tshiab ntawm tus substituents twb tam sim no nyob rau hauv cov qauv. Aldehydes thiab ketones muaj xws li tag nrho cov organic tebchaw yog cov feem ntau reactive. Ntxiv mus, nyob rau hauv cov tshuaj cov ntsiab lus uas ua ntej ob ntau npaum li cas kom nquag plias. Rau aldehydes yog heev raug oxidation cov tshuaj tiv thaiv, hloov, polymerization, tsis tas li ntawd thiab hws. Ketones kuj tsis txhawb tus polymerization cov tshuaj tiv thaiv.

Kev npaj ntawm uas muaj ntxhiab aldehydes, tshwj xeeb tshaj yog benzaldehyde tebchaw los ntawm oxidation ntawm hydrocarbon cua sib tov industrially ua. Tej tshua yog nqa tawm nyob rau hauv tshuaj cov nroj tsuag siv oxides ntawm ntau yam co, e.g., vanadium oxide. Tsis tas li ntawd, rau qhov synthesis ntawm uas muaj ntxhiab aldehyde yuav tau mus thov cov kev siv nyob rau hauv qhov kev npaj ntawm lub tebchaw ntawm aliphatic series.

Aromatic aldehydes yog hais lom zem ntau insoluble nyob rau hauv aqueous nruab nrab kua nrog ib tug peculiar pungent tsis hnov tsw ntawm iab almonds. Qhov ntau tej thaj chaw deb ntawm lub benzene lub nplhaib ntawm cov carbonyl pab pawg neeg, lawv muaj, cov sharper yuav lawv tsw. Aromatic aldehydes tshuaj zog uas yog kev lom zem ntau zoo sib xws, nrog rau cov tib aliphatic tebchaw vim lub kev sib nrig sib ntxwv ntawm lub benzene nplhaib thiab ib tug carbonyl pab pawg neeg, muaj tej yam kev tshuaj zog thiab lub cev tus yam ntxwv. Piv txwv li, lawv yuav tsum tau nkag oxidized mus rau lub carboxylic acid ua raws li los ntawm txo mus rau lub sib nug xov alcohols thiab hydrocarbons. Ib tug propionaldehyde, uas yog tov zoo nrog ntau hom ntawm cov organic solvents nyob rau hauv lub xub ntiag ntawm haum catalysts yog hloov dua siab tshiab rau propionic acid thiab lub hydrogenation - nyob rau hauv propanol.

Rau lub synthesis ntawm uas muaj ntxhiab ketones yuav ua tau ispolzony ntau txoj kev. Piv txwv li, lub alkaline hydrolysis txheej txheem geminal dihalides, dehydrogenation, oxidation ntawm lub sib nug xov theem nrab monohydric cawv tebchaw, thiab lwm tus neeg. Txawm li cas los, qhov yooj yim txoj kev npaj cov tebchaw yog tus acylation ntawm uas muaj ntxhiab tebchaw. Tag nrho aldehydes thiab ketones muaj ib tug electrophilic center, txig nrog nucleophilic reagents series.

Tej uas muaj ntxhiab tebchaw nrog electron-tso substituents kuj yooj yim nkag mus rau hauv acylation tshua. Ketones ntawm lub molecular qauv yog kua los yog khib nyiab nrog ib tug ntxiag floral tsw, insoluble nyob rau hauv dej, uas tso cai rau lawv mus tau lug siv nyob rau hauv lub naj hoom kev lag luam.