Cov uas tsim ntsev, ntu 4 Bromine

Lwm cov khoom los ntawm tsev neeg halogen yog bromine. Nws nyob ib qho chaw nruab nrab ntawm cov tshuaj chlorine thiab iodine (ua ke tsim cov halogen subfamily), thiab nws cov khoom yog qhov nruab nrab piv rau nws cov neeg nyob ze rau saum thiab hauv qab ntawm pab pawg. Txawm li cas los xij, leej twg xav tias qhov no yog qhov tsis txaus ntseeg yuav raug yuam kev.

Piv txwv li, bromine tsuas yog cov kua ntawm cov hlau tsis yog hlau, thiab nws cov xim kuj tseem nyob hauv lub ntiaj teb ntawm cov khoom. Qhov tseem ceeb, txawm li cas los xij, yog qhov kev sim nthuav dav tuaj yeem nqa nrog nws hauv tsev.

- Tej yam tsw phem nyob ntawm no! -

...... exclaimed Fabkis chemist Joseph Gay-Lussacthaum lub caij ntuj sov xyoo 1826, sawv cev ntawm Fab Kis Academy, nws tau tshawb xyuas daim ntawv tshaj tawm txog kev tshawb pom ntawm cov khoom tshiab. Nws tus sau tau dav dua tsis paub Antoine Cov Me Nyuam. Ib xyoo dhau los, tus neeg muaj hnub nyoog 23 xyoos no tau tshawb nrhiav qhov ua tau ntawm kev ua iodine los ntawm cov tshuaj brewing tshuav los ntawm crystallization ntawm pob zeb ntsev los ntawm dej hiav txwv (ib txoj kev siv los ua ntsev hauv cov huab cua sov xws li Fabkis Mediterranean ntug dej hiav txwv). Chlorine bubbled los ntawm kev daws, tshem tawm cov iodine los ntawm nws cov ntsev. Nws tau txais lub caij, tab sis pom lwm yam - ib zaj duab xis ntawm ib tug yellowish kua nrog ib tug muaj zog tsw. Nws cais nws thiab ces muab sib sau ua ke. Cov residue tau dhau los ua cov kua xim av tsaus, tsis zoo li lwm yam khoom paub. Qhov kev sim ntawm Balar tau pom tias qhov no yog ib qho tshiab. Yog li ntawd, nws tau xa tsab ntawv ceeb toom mus rau Fabkis Academy thiab tos nws qhov kev txiav txim. Tom qab Balar qhov kev tshawb pom tau lees paub, ib lub npe tau thov rau lub caij. bromine, muab los ntawm Greek bromos, i.e. stench, vim hais tias tus ntxhiab tsw ntawm bromine tsis qab ntxiag (1).

Ceev faj Cov ntxhiab tsw phem tsis yog qhov tsis zoo ntawm bromine nkaus xwb. Cov khoom no tsuas yog muaj teeb meem zoo li cov halogens siab dua, thiab, ib zaug ntawm daim tawv nqaij, tawm qhov txhab uas nyuaj rau kho. Yog li ntawd, tsis muaj teeb meem koj yuav tsum tau txais bromine hauv nws daim ntawv ntshiab thiab tsis txhob nqus cov ntxhiab ntawm nws cov tshuaj.

hiav txwv dej ntsiab

Dej hiav txwv muaj yuav luag tag nrho cov bromine uas muaj nyob rau hauv lub ntiaj teb no. Kev raug tshuaj chlorine ua rau tso tawm ntawm bromine, uas volatilizes nrog huab cua siv los tshuab dej. Nyob rau hauv lub receiver, bromine yog condensed thiab ces purified los ntawm distillation. Vim muaj kev sib tw pheej yig dua thiab tsis tshua muaj kev cuam tshuam, bromine tsuas yog siv thaum xav tau. Ntau yam kev siv tau ploj mus, xws li nyiaj bromide hauv kev yees duab, coj cov khoom siv roj av, thiab cov tshuaj tua hluav taws halon. Bromine yog cov khoom siv ntawm bromine-zinc roj teeb, thiab nws cov khoom sib txuas yog siv los ua tshuaj, dyes, additives los txo cov nplaim hluav taws xob ntawm cov yas, thiab cov khoom tiv thaiv nroj tsuag.

Chemically, bromine tsis txawv ntawm lwm yam halogens: nws tsim muaj zog hydrobromic acid HBr, ntsev nrog bromine anion thiab qee cov pa oxygen thiab lawv cov ntsev.

Bromine kws tshuaj ntsuam

Cov tshuaj tiv thaiv tus yam ntxwv ntawm bromide anion zoo ib yam li cov kev sim ua rau chlorides. Tom qab ntxiv ib qho kev daws ntawm silver nitrate AgNO₃ ib tug tsis zoo soluble precipitate ntawm AgBr precipitates, darkening nyob rau hauv lub teeb vim photochemical decomposition. Lub precipitate muaj xim daj (qhov sib piv rau AgCl dawb thiab daj AgI) thiab tsis zoo soluble thaum NH ammonia tov ntxiv._{3aq ua} (uas txawv ntawm AgCl, uas yog soluble heev nyob rau hauv cov xwm txheej no) (2). 

2. Kev sib piv ntawm cov xim ntawm cov nyiaj halides - hauv qab no koj tuaj yeem pom lawv cov kev lwj tom qab raug lub teeb.

Txoj hauv kev yooj yim tshaj plaws los txheeb xyuas bromides yog oxidize lawv thiab txiav txim siab muaj cov bromine dawb. Rau kev kuaj koj yuav xav tau: potassium bromide KBr, potassium permanganate KMnO₄, sulfuric acid tov (VI) H₂SO₄ thiab cov organic hnyav (piv txwv li, pleev xim rau nyias). Ncuav me me ntawm KBr thiab KMnO cov kev daws teeb meem rau hauv lub raj ntsuas.₄thiab tom qab ntawd ob peb tee kua qaub. Cov ntsiab lus tam sim ntawd ua yellowish (thaum chiv keeb nws yog ntshav los ntawm ntxiv poov tshuaj permanganate):

2 kwm₄ +10KBr +8H₂SO4 → 2MnSO₄ + 6 txhiab₂SO₄ +5 Nr₂ + 8 hli₂Hais txog Ntxiv kev pab

3. Bromine muab rho tawm los ntawm aqueous txheej (hauv qab) xim cov organic solvent txheej liab-xim av (sab saum toj).

hnyav thiab co lub vial kom sib tov cov ntsiab lus. Tom qab tev tawm, koj yuav pom tias cov organic txheej tau noj cov xim liab xim av. Bromine dissolves zoo dua nyob rau hauv cov kua uas tsis yog-polar thiab mus los ntawm dej mus rau hnyav. Observed phenomenon khau raj (3). 

Bromine dej hauv tsev

bromine dej yog ib qho kev daws teeb meem uas tau txais kev lag luam los ntawm kev ua kom bromine hauv dej (li 3,6 g ntawm bromine ib 100 g ntawm dej). Nws yog ib tug reagent siv los ua ib tug me me oxidizing tus neeg saib xyuas thiab xyuas cov unsaturated xwm ntawm cov organic tebchaw. Txawm li cas los xij, dawb bromine yog ib yam khoom txaus ntshai, thiab ntxiv rau, cov dej bromine tsis ruaj khov (bromine evaporates los ntawm kev daws thiab reacts nrog dej). Yog li ntawd, nws yog qhov zoo tshaj kom tau txais nws me ntsis workaround thiab tam sim ntawd siv nws rau kev sim.

Koj twb tau kawm thawj txoj hauv kev los kuaj xyuas bromides: oxidation ua rau tsim cov bromine dawb. Lub sijhawm no, ntxiv ob peb tee ntawm H rau cov tshuaj potassium bromide KBr hauv lub khob.₂SO₄ thiab ib feem ntawm hydrogen peroxide (3% H₂O₂ siv los ua tshuaj tua kab mob). Tom qab ib pliag, qhov sib tov ua yellowish:

2 KBr+H₂O₂ +H₂SO₄ → K₂SO₄ + Nr₂ + 2 hli₂O

Cov dej bromine yog li tau txais yog qias neeg, tab sis X yog qhov kev txhawj xeeb xwb.₂O₂. Yog li ntawd, nws yuav tsum tau muab tshem tawm nrog manganese dioxide MnO.₂uas yuav decompose tshaj hydrogen peroxide. Txoj kev yooj yim tshaj plaws kom tau txais cov khoom sib xyaw yog los ntawm cov khoom siv pov tseg (tseem hu ua R03, R06), qhov twg nws yog nyob rau hauv daim ntawv ntawm ib qho tsaus nti puv lub khob zinc. Muab ib tug pinch ntawm loj nyob rau hauv lub hwj, thiab tom qab cov tshuaj tiv thaiv, ncuav tawm lub supernatant, thiab lub reagent yog npaj txhij.

Lwm txoj kev yog electrolysis ntawm aqueous tov ntawm KBr. Yuav kom tau txais cov tshuaj ntshiab bromine, nws yog ib qho tsim nyog los tsim ib lub diaphragm electrolyzer, i.e. tsuas yog faib lub beaker nrog ib daim duab los qhia (qhov no koj yuav txo tau qhov sib xyaw ntawm cov khoom siv tshuaj tiv thaiv ntawm cov electrodes). Ib tug graphite stick coj los ntawm cov khoom pov tseg ntawm tes 3 tau sau tseg saum toj no yuav siv los ua ib qho zoo electrode, thiab cov ntsia hlau zoo tib yam li cov electrode tsis zoo. Lub zog hluav taws xob yog 4,5 V npib tooj ntawm tes roj teeb. Muab cov tshuaj KBr rau hauv lub beaker, ntxig cov electrodes nrog cov xov hlau txuas, thiab txuas lub roj teeb rau hauv cov xov hlau. Nyob ze ntawm qhov zoo electrode, cov tshuaj yuav tig daj (qhov no yog koj cov dej bromine), thiab hydrogen npuas yuav tsim ntawm qhov tsis zoo electrode (4). Muaj ib qho tsis hnov ​​tsw ntawm bromine saum lub khob. Kos cov tshuaj nrog ib tug syringe los yog pipette.

4. Homemade diaphragm cell ntawm sab laug thiab tib lub xov tooj ntawm tes hauv kev tsim cov dej bromine (txoj cai). Lub reagent accumulates nyob ib ncig ntawm lub zoo electrode; hydrogen npuas yog pom ntawm qhov tsis zoo electrode.

Koj tuaj yeem khaws cov dej bromine rau lub sijhawm luv luv hauv lub thawv kaw ntom ntom, tiv thaiv lub teeb thiab hauv qhov chaw txias, tab sis nws yog qhov zoo dua los sim tam sim ntawd. Yog tias koj ua cov ntaub ntawv hmoov txhuv nplej siab iodine raws li daim ntawv qhia los ntawm ntu thib ob ntawm lub voj voog, muab cov dej bromine tso rau ntawm daim ntawv. Ib qho chaw tsaus yuav tshwm sim tam sim ntawd, qhia txog kev tsim cov iodine dawb:

2 KIA + Br.₂ → i₂ + KWV

Ib yam li bromine tau txais los ntawm dej hiav txwv los ntawm kev tshem tawm los ntawm bromides nrog lub zog oxidizing tus neeg sawv cev (), yog li bromine tshem tawm iodine tsis muaj zog dua li nws los ntawm iodides (tau kawg, chlorine tseem yuav hloov iodine).

Yog tias koj tsis muaj cov hmoov txhuv nplej siab iodine, ncuav cov tshuaj potassium iodide rau hauv ib lub raj kuaj thiab ntxiv ob peb tee dej bromine. Cov tshuaj darkens, thiab thaum lub starch qhia (ib tug ncua kev kawm ntawv ntawm qos yaj ywm hmoov nyob rau hauv dej) ntxiv, nws tig xiav tsaus - qhov tshwm sim qhia tau hais tias cov tsos ntawm dawb iodine (5). 

5. Kev kuaj pom ntawm bromine. Saum toj no - hmoov txhuv nplej siab iodine ntawv, hauv qab no - ib tug tov ntawm poov tshuaj iodide nrog ib tug starch qhia (sab laug - reagents rau cov tshuaj tiv thaiv, nyob rau sab xis - qhov tshwm sim ntawm kev sib tov cov ntsiab lus).

Ob chav ua noj sim.

Ntawm ntau qhov kev sim nrog dej bromine, kuv qhia ob qho uas koj yuav xav tau cov tshuaj reagents los ntawm chav ua noj. Thawj zaug, tshem tawm ib lub raj mis ntawm rapeseed roj,

7. Cov tshuaj tiv thaiv ntawm bromine dej nrog zaub roj. Sab saum toj txheej ntawm cov roj yog pom (sab laug) thiab hauv qab txheej ntawm cov dej stained nrog bromine ua ntej cov tshuaj tiv thaiv (sab laug). Tom qab cov tshuaj tiv thaiv (txoj cai), txheej aqueous tau hloov pauv.

sunflower los yog txiv roj roj. Ncuav me me ntawm cov roj zaub rau hauv lub raj tshuaj nrog dej bromine thiab co cov ntsiab lus kom cov reagents sib tov zoo. Raws li lub labile emulsion tawg, roj yuav nyob rau saum toj (tsawg dua li dej) thiab dej bromine hauv qab. Txawm li cas los xij, txheej dej tau poob nws cov xim daj. Cov nyhuv no " txwv tsis pub" cov tshuaj aqueous thiab siv nws los cuam tshuam nrog cov khoom ntawm cov roj (6). 

Cov roj zaub muaj ntau heev unsaturated fatty acids (sib txuas nrog glycerin los ua rog). Bromine atoms txuas rau ob daim ntawv cog lus hauv cov molecules ntawm cov kua qaub, tsim cov bromine derivatives sib xws. Ib qho kev hloov ntawm cov xim ntawm cov dej bromine yog ib qho kev qhia tias cov organic compounds tsis muaj nyob hauv cov qauv kuaj, i.e. cov tebchaw uas muaj ob lossis triple bonds ntawm carbon atoms (7). 

Rau qhov kev sim thib ob hauv chav ua noj, npaj baking soda, piv txwv li sodium bicarbonate, NaHCO.₃, thiab ob lub suab thaj - qabzib thiab fructose. Koj tuaj yeem yuav cov dej qab zib thiab qabzib ntawm lub khw muag khoom noj, thiab fructose ntawm cov ntshav qab zib kiosk lossis cov khw muag khoom noj qab haus huv. Glucose thiab fructose tsim sucrose, uas yog cov suab thaj ntau. Tsis tas li ntawd, lawv yog cov zoo sib xws hauv cov khoom thiab muaj tib lub qauv tag nrho, thiab yog tias qhov no tsis txaus, lawv yooj yim dhau mus rau ib leeg. Muaj tseeb, muaj qhov sib txawv ntawm lawv: fructose yog qab zib dua li qabzib, thiab hauv kev daws nws tig lub dav hlau ntawm lub teeb mus rau lwm qhov. Txawm li cas los xij, rau kev txheeb xyuas, koj yuav siv qhov sib txawv ntawm cov qauv tshuaj: qabzib yog ib qho aldehyde, thiab fructose yog ketone.

7. Cov tshuaj tiv thaiv ntxiv ntawm bromine rau kev khi

Tej zaum koj yuav nco ntsoov tias txo cov suab thaj raug txheeb xyuas los ntawm kev kuaj Trommer thiab Tollens. Sab nrauv saib ntawm cib Cu deposit₂O (hauv thawj qhov kev sim) lossis daim iav nyiaj (hauv qhov thib ob) qhia tias muaj cov tshuaj txo qis, xws li aldehydes.

Txawm li cas los xij, cov kev sim no tsis paub qhov txawv ntawm cov piam thaj aldehyde thiab fructose ketone, vim tias fructose yuav hloov nws cov qauv hauv nruab nrab cov tshuaj tiv thaiv, tig mus rau hauv qabzib. Yuav tsum muaj ib tug nyias reagent.

Halogen zoo li 

Muaj ib pab pawg ntawm cov tshuaj sib xyaw ua ke uas zoo sib xws hauv cov khoom zoo sib xws. Lawv tsim cov kua qaub ntawm cov mis HX thiab ntsev nrog mononegative X- anions, thiab cov kua qaub no tsis tsim los ntawm oxides. Piv txwv ntawm cov pseudohalogens yog cov tshuaj lom hydrocyanic acid HCN thiab tsis muaj teeb meem thiocyanate HSCN. Qee tus ntawm lawv txawm tsim cov molecules diatomic, xws li cyanogen (CN).₂.

Qhov no yog qhov uas dej bromine tuaj ua si. Ua cov tshuaj: qabzib nrog ntxiv ntawm NaHCO₃ thiab fructose, kuj nrog ntxiv ntawm ci dej qab zib. Ncuav cov kua nplaum npaj rau hauv ib lub raj kuaj nrog dej bromine, thiab cov tshuaj fructose rau hauv lwm qhov, kuj nrog dej bromine. Qhov txawv yog pom tseeb: bromine dej decolorized nyob rau hauv qhov kev txiav txim ntawm cov kua qab zib, thiab fructose tsis ua rau muaj kev hloov. Ob lub suab thaj tsuas tuaj yeem sib txawv hauv ib puag ncig alkaline me ntsis (muab nrog sodium bicarbonate) thiab nrog cov tshuaj oxidizing me me, piv txwv li dej bromine. Kev siv cov tshuaj alkaline uas muaj zog heev (yuav tsum tau kuaj Trommer thiab Tollens) ua rau kev hloov pauv sai ntawm ib lub suab thaj mus rau lwm qhov thiab kev hloov pauv ntawm cov dej bromine kuj los ntawm fructose. Yog tias koj xav paub, rov kuaj dua siv sodium hydroxide es tsis txhob ci dej qab zib.