Carboxylic acids: lub cev muaj zog. Cov ntsev ntawm carboxylic acids

2024 Tus sau: Angel Austin | [email protected]. Kawg hloov kho: 2023-12-17 05:28

Yuav luag txhua tus muaj kua qaub nyob hauv tsev. Thiab cov neeg feem coob paub tias nws lub hauv paus yog acetic acid. Tab sis nws yog dab tsi los ntawm kev tshuaj ntsuam xyuas? Dab tsi lwm cov organic tebchaw ntawm no series muaj nyob thiab lawv cov yam ntxwv yog dab tsi? Cia peb sim nkag siab txog qhov teeb meem no thiab kawm txog kev txwv monobasic carboxylic acids. Ntxiv mus, tsis yog tsuas yog acetic acid yog siv nyob rau hauv lub neej txhua hnub, tab sis kuj ib co lwm yam, thiab cov derivatives ntawm cov acids yog feem ntau nquag qhua nyob rau hauv txhua lub tsev.

Class of carboxylic acids: general yam ntxwv

Los ntawm qhov pom ntawm kev tshawb fawb ntawm chemistry, chav kawm ntawm cov tebchaw no suav nrog oxygen-muaj cov molecules uas muaj cov pab pawg tshwj xeeb ntawm atoms - pawg carboxyl ua haujlwm. Nws zoo li -COOH. Yog li, cov mis mos uas tag nrho cov saturated monobasic carboxylic acids muaj yog: R-COOH, qhov twg R yog ib tug radical particle uas muaj peev xwm suav nrog ib tug naj npawb ntawm carbon atoms.

Raws li qhov no, lub ntsiab lus ntawm chav kawm ntawm cov khoom sib txuas tuaj yeem muab tau raws li hauv qab no. Carboxylic acids yog cov organic oxygen molecules, uas suav nrog ib lossis ntau pawg ua haujlwm -COOH - carboxyl pawg.

Qhov tseeb tias cov tshuaj no tshwj xeeb rau cov kua qaub yog piav qhia los ntawm kev txav ntawm hydrogen atom hauv carboxyl. Lub electron ceev yog faib unevenly, vim oxygen yog cov feem ntau electronegative nyob rau hauv pab pawg neeg. Los ntawm qhov no, O-H daim ntawv cog lus muaj zog polarized, thiab hydrogen atom ua rau tsis muaj zog heev. Nws yog yooj yim cais tawm, nkag mus rau hauv tshuaj lom neeg kev sib tshuam. Yog li ntawd, cov kua qaub nyob rau hauv cov cim qhia tau zoo sib xws:

• phenolphthalein - tsis muaj xim;
• litmus - red;
• universal - liab;
• methylorange - liab thiab lwm yam.

Vim yog hydrogen atom, carboxylic acids nthuav tawm oxidizing zog. Txawm li cas los xij, muaj lwm cov atoms tso cai rau lawv rov qab los, koom nrog ntau lwm yam kev sib cuam tshuam.

Kev faib tawm

Muaj ob peb lub ntsiab lus uas carboxylic acids muab faib ua pawg. Thawj ntawm cov no yog qhov xwm txheej ntawm radical. Raws li qhov xwm txheej no, lawv paub qhov txawv:

• Alicyclic acids. Piv txwv: cinchona.
• Aromatic. Piv txwv: benzoic.
• Aliphatic. Piv txwv li: acetic, acrylic, oxalic thiab lwm yam.
• Heterocyclic. Piv txwv: nicotine.

Yog tias peb tham txog kev sib cog lus hauv ib lub molecule, ces peb kuj tuaj yeem paub qhov txawv ntawm ob pawg acids:

• marginal - tag nrho cov kev sib txuas nkaus xwbib leeg;
• unlimited - muaj ob npaug, ib zaug lossis ntau yam.

Tsis tas li ntawd, tus naj npawb ntawm cov pab pawg ua haujlwm tuaj yeem ua lub cim ntawm kev faib tawm. Yog li, cov pawg hauv qab no yog qhov txawv.

1. Single-basic - tsuas yog ib qho -COOH-group. Piv txwv li: formic, stearic, butane, valeric thiab lwm yam.
2. Dibasic - feem, ob pawg -COOH. Piv txwv li: oxalic, malonic thiab lwm yam.
3. Multibasic - txiv qaub, mis nyuj thiab lwm yam.

Ntxiv rau hauv kab lus no peb yuav tham txog tsuas yog txwv cov monobasic carboxylic acids ntawm aliphatic series.

Discovery keeb kwm

Winemaking tau vam meej txij thaum ancient sij hawm. Thiab, raws li koj paub, ib qho ntawm nws cov khoom yog acetic acid. Yog li ntawd, keeb kwm ntawm kev muaj koob meej ntawm cov chav kawm ntawm cov khoom sib txuas no tau rov qab mus rau lub sijhawm Robert Boyle thiab Johann Glauber. Txawm li cas los xij, rau lub sijhawm ntev nws tsis tuaj yeem ua kom pom cov tshuaj lom neeg ntawm cov molecules.

Tom qab tag nrho, cov kev xav ntawm cov neeg tseem ceeb tau kav ntev ntev, tsis lees paub qhov muaj peev xwm tsim cov organics yam tsis muaj tsiaj nyob. Tab sis twb nyob rau hauv 1670, D. Ray tswj kom tau tus thawj heev neeg sawv cev - methane los yog formic acid. Nws ua li no los ntawm cua sov cov ntsaum nyob hauv lub khob.

Tom qab ntawd, kev ua haujlwm ntawm cov kws tshawb fawb Berzelius thiab Kolbe tau pom tias muaj peev xwm ua kom cov khoom sib txuas no los ntawm cov tshuaj inorganic (los ntawm distillation ntawm charcoal). Qhov tshwm sim yog acetic acid. Yog li, carboxylic acids (lub cev muaj zog, qauv) tau kawm thiab qhov pib tau muab tso rau kev tshawb pom ntawm txhua tus. Lwm cov neeg sawv cev ntawm ib tug xov tooj ntawm aliphatic tebchaw.

Lub cev muaj zog

Hnub no, tag nrho lawv cov neeg sawv cev tau kawm kom ntxaws. Rau txhua tus ntawm lawv, koj tuaj yeem pom tus yam ntxwv ntawm txhua qhov kev hwm, suav nrog kev siv hauv kev lag luam thiab nyob hauv qhov xwm txheej. Peb yuav saib seb cov carboxylic acids yog dab tsi, lawv lub cev thiab lwm yam tsis zoo.

Yog li, muaj ob peb yam tseem ceeb tsis muaj.

1. Yog tias cov pa roj carbon atom hauv cov saw tsis tshaj tsib, ces cov no yog cov ntxhiab tsw ntxhiab, txawb thiab cov kua dej tsis haum. Saum tsib - hnyav oily tshuaj, txawm ntau - khoom, paraffin-zoo li.
2. Qhov ntom ntawm thawj ob tus neeg sawv cev tshaj ib tus. Txhua yam yog sib dua li dej.
3. Boiling point: qhov loj dua cov saw, tus nqi siab dua. Qhov ntau branched tus qauv, qhov qis.
4. Melting point: nyob ntawm qhov sib npaug ntawm cov pa roj carbon atoms hauv cov saw hlau. Txawm tus muaj nws siab dua, khib tus muaj nws qis.
5. Dissols zoo heev hauv dej.
6. Muaj peev xwm tsim cov ntawv cog lus muaj zog hydrogen.

Cov yam ntxwv zoo li no tau piav qhia los ntawm qhov sib luag ntawm cov qauv, thiab yog li cov qauv siv lead ua lattice, nws lub zog. Qhov yooj yim thiab ntau cov qauv molecules, qhov ua tau zoo dua uas carboxylic acids muab. Cov khoom ntawm lub cev ntawm cov tebchaw no ua rau nws tuaj yeem txiav txim siab thaj chaw thiab txoj hauv kev siv lawv hauv kev lag luam.

tshuaj muaj zog

Raws li peb tau hais saum toj no, cov kua qaub no tuaj yeem nthuav tawm cov khoom sib txawv. Teb nroglawv kev koom tes yog ib qho tseem ceeb rau kev lag luam synthesis ntawm ntau lub tebchaw. Cia peb qhia txog cov khoom tseem ceeb tshaj plaws uas muaj monobasic carboxylic acid tuaj yeem nthuav tawm.

1. Dissociation: R-COOH=RCOO^- + H⁺.
2. Qhia cov kua qaub, uas yog, nws cuam tshuam nrog cov oxides yooj yim, nrog rau lawv cov hydroxides. Nws cuam tshuam nrog cov hlau yooj yim raws li cov qauv txheej txheem (uas yog, tsuas yog nrog cov uas sawv ntsug ua ntej hydrogen hauv cov kab hluav taws xob).
3. Coj zoo li lub hauv paus nrog cov kua qaub uas muaj zog dua (inorganic).
4. Yuav txo tau haus cawv thawj zaug.
5. Cov tshuaj tiv thaiv tshwj xeeb - esterification. Qhov no yog kev cuam tshuam nrog cawv los tsim cov khoom lag luam nyuaj - ether.
6. Cov tshuaj tiv thaiv ntawm decarboxylation, uas yog, tshem tawm cov pa roj carbon dioxide molecule los ntawm cov khoom sib xyaw.
7. Muaj peev xwm cuam tshuam nrog halides ntawm cov ntsiab lus xws li phosphorus thiab sulfur.

Nws pom tseeb npaum li cas carboxylic acids muaj ntau yam. Lub cev muaj zog, nrog rau cov tshuaj lom neeg, muaj ntau haiv neeg. Tsis tas li ntawd, nws yuav tsum tau hais tias, nyob rau hauv dav dav, nyob rau hauv cov nqe lus ntawm lub zog raws li acids, tag nrho cov organic molecules yog tsis muaj zog npaum li cas piv rau lawv inorganic counterparts. Lawv dissociation tas li tsis pub tshaj 4, 8.

Txoj kev tau txais

Muaj ntau ntau txoj hauv kev uas cov saturated carboxylic acids tuaj yeem tau.

1. Hauv chav kuaj, qhov no yog ua los ntawm oxidation:

• cawv;
• aldehydes;
• alkynes;
• alkylbenzenes;
• kev puas tsuaj ntawm alkenes.

2. Hydrolysis:

• esters;
• nitriles;
• amide;
• trihaloalkanes.

3. Decarboxylation - tshem tawm CO molecule ₂.

4. Hauv kev lag luam, synthesis yog ua los ntawm oxidation ntawm hydrocarbons nrog ntau cov pa roj carbon atoms hauv cov saw hlau. Cov txheej txheem yog ua nyob rau hauv ob peb theem nrog tso tawm ntau by-products.

5. Qee tus neeg cov kua qaub (formic, acetic, butyric, valeric, thiab lwm yam) tau txais los ntawm kev siv cov khoom xyaw ntuj.

Cov ntsiab lus tseem ceeb ntawm saturated carboxylic acids: ntsev

Cov ntsev ntawm carboxylic acids yog cov khoom siv tseem ceeb hauv kev lag luam. Lawv tau txais los ntawm kev sib cuam tshuam ntawm tom kawg nrog:

• metals;
• basic oxides;
• amphoteric oxides;
• alkali;
• amphoteric hydroxides.

Qhov tseem ceeb ntawm lawv yog cov uas tsim los ntawm cov hlau alkali sodium thiab potassium thiab cov kua qaub siab tshaj plaws - palmitic, stearic. Tom qab tag nrho, cov khoom ntawm xws li kev sib cuam tshuam yog xab npum, kua thiab khoom.

Yog tias peb tham txog cov tshuaj tiv thaiv zoo ib yam: 2C₁₇H₃₅-COOH + 2Na=2C ₁₇ H₃₅COONa + H₂, cov khoom lag luam - sodium stearate - yog los ntawm nws qhov xwm txheej ib txwm siv xab npum ntxhua khaub ncaws.

Yog koj hloov cov kua qaub nrogpalmitic, thiab hlau rau poov tshuaj, koj tau txais poov tshuaj palmitate - kua xab npum ntxuav tes. Yog li ntawd, nws tuaj yeem hais nrog qhov tseeb tias cov ntsev ntawm carboxylic acids yog qhov tseem ceeb ntawm cov organic. Lawv cov kev lag luam tsim thiab siv tsuas yog colossal hauv nws cov nplai. Yog tias koj xav txog cov tshuaj xab npum ntau npaum li cas txhua tus neeg hauv ntiaj teb siv, ces nws yooj yim rau kev xav txog cov nplai no.

Esters ntawm carboxylic acids

Ib pab pawg tshwj xeeb ntawm cov tebchaw uas muaj nws qhov chaw hauv kev faib tawm cov tshuaj organic. Qhov no yog chav kawm ntawm esters. Lawv yog tsim los ntawm cov tshuaj tiv thaiv ntawm carboxylic acids nrog cawv. Lub npe ntawm cov kev sib cuam tshuam no yog cov tshuaj tiv thaiv esterification. Kev pom dav dav tuaj yeem sawv cev los ntawm qhov sib npaug:

R, -COOH + R"-OH=R, -COOR" + H_{2 O.}

Cov khoom lag luam nrog ob lub radicals yog ester. Pom tseeb, raws li qhov tshwm sim ntawm cov tshuaj tiv thaiv, cov carboxylic acid, cawv, ester thiab dej tau hloov pauv tseem ceeb. Yog li, hydrogen tawm hauv cov kua qaub molecule nyob rau hauv daim ntawv ntawm ib tug cation thiab ntsib nrog ib tug hydroxo pab pawg neeg uas tau cais tawm ntawm cawv. Qhov tshwm sim yog dej molecule. Cov pab pawg sab laug ntawm cov kua qaub txuas cov radical los ntawm cawv rau nws tus kheej, tsim cov ester molecule.

Vim li cas cov kev cuam tshuam no tseem ceeb heev thiab qhov kev lag luam tseem ceeb ntawm lawv cov khoom yog dab tsi? Qhov khoom yog cov esters siv xws li:

• khoom noj khoom haus ntxiv;
• aromatics;
• khoom ntawm naj hoom;
• solvents;
• khoom ntawm cov kua roj vanish, xim, yas;
• tshuaj thiab ntau dua.

Nws paub meej tias lawv thaj chaw siv dav txaus los ua pov thawj qhov ntim ntawm kev tsim khoom hauv kev lag luam.

YEthanoic acid (acetic)

Qhov no yog txwv tsis pub monobasic carboxylic acid ntawm aliphatic series, uas yog ib qho ntawm feem ntau ntawm cov khoom ntim thoob plaws ntiaj teb. Nws cov qauv yog CH₃COOH. Xws li kev nthuav dav yog vim nws cov khoom. Tom qab tag nrho, thaj chaw ntawm nws siv yog dav heev.

1. Nws yog kev noj haus ntxiv raws li txoj cai E-260.
2. Used hauv kev lag luam khoom noj rau kev khaws cia.
3. Siv tshuaj rau kev sib txuas ntawm cov tshuaj.
4. Cov khoom xyaw thaum ua cov tshuaj tsw qab.
5. Solvent.
6. Pib koom hauv txheej txheem luam ntawv, dyeing fabrics.
7. Ib qho tsim nyog hauv kev cuam tshuam ntawm cov tshuaj synthesis ntawm ntau yam tshuaj.

Hauv lub neej txhua hnub, nws cov tshuaj 80% feem ntau yog hu ua vinegar essence, thiab yog tias koj dilute nws mus rau 15%, koj tsuas yog vinegar. Ntshiab 100% acid hu ua glacial acetic acid.

Formic acid

Tus thawj thiab yooj yim tshaj tus sawv cev ntawm chav kawm no. Formula - NCOON. Nws kuj yog ib qho khoom noj ntxiv raws li txoj cai E-236. Nws cov peev txheej ntuj:

• nettle;
• koob;
• fruits.

siv tseem ceeb:

• rau kev txuag thiab npaj zaub mov;
• siv los tswj cov kab mob;
• rau dyeing fabrics, staining details;
• howkuab tshuaj;
• paj;
• hauv tshuaj - rau tshuaj tua kab mob thiab khoom siv;
• kom tau txais cov pa roj carbon monoxide hauv chav kuaj.

Kuj nyob rau hauv kev phais, kev daws cov kua qaub no yog siv los ua tshuaj tua kab mob.