624-28-2

Basic information

• Product Name: 2,5-Dibromopyridine
• Synonyms: PYRIDINE, 2,5-DIBROMO-;2,5-DIBROMOPYRIDINE;Dibromopyridine;2,5-Dibromopyridine, 97+%;2,5-dibromopyridin;2,5-DIBROMOPYRIDINE 2,5-DIBROMOPYRIDINE;2,5-Dibromo pyridine ,98%;5-DibroMopyridine
• CAS NO: 624-28-2
• Molecular Formula: C₅H₃Br₂N
• Molecular Weight: 236.89
• EINECS: 210-839-6
• Product Categories: Nitrogen cyclic compounds;blocks;Bromides;Pyridines;pyridine derivative;Pyridines, Pyrimidines, Purines and Pteredines;Halides;Pyridine;Pyridines derivates;Aromatics Compounds;Bromopyridines;Halopyridines;Pyridine series;Aromatics;Bases & Related Reagents;Nucleotides;C5Heterocyclic Building Blocks;Halogenated Heterocycles;Heterocyclic Building Blocks;Brominated heterocyclic series;Building Blocks;C5;Chemical Synthesis;Halogenated Heterocycles;Heterocyclic Building Blocks;alkyl bromide
• Mol File: 624-28-2.mol
• Article Data: 16

Chemical Properties

• Melting Point: 92-95 °C(lit.)
• Boiling Point: 235 °C / 772mmHg
• Flash Point: 96.4 °C
• Appearance: Almost white or light beige to brown/Crystalline Powder
• Density: 2.0383 (rough estimate)
• Vapor Pressure: 0.0754mmHg at 25°C
• Refractive Index: 1.5800 (estimate)
• Storage Temp.: Store below +30°C.
• Solubility: Chloroform (Slightly), Methanol (Slightly)
• PKA: -1.57±0.10(Predicted)
• Water Solubility: insoluble
• BRN: 109099
• CAS DataBase Reference: 2,5-Dibromopyridine(CAS DataBase Reference)
• NIST Chemistry Reference: 2,5-Dibromopyridine(624-28-2)
• EPA Substance Registry System: 2,5-Dibromopyridine(624-28-2)

Safety Data

• Hazard Codes: Xi,Xn
• Statements: 36/37/38-20/21/22
• Safety Statements: 26-37/39-36/37/39-36
• RIDADR: UN2811
• WGK Germany: 3
• HazardClass: IRRITANT
• Hazardous Substances Data: 624-28-2(Hazardous Substances Data)

Usage

Uses

2,5-Dibromopyridine (cas# 624-28-2) is a compound useful in organic synthesis.

Chemical Properties

Off-White Crystals

InChI:InChI=1/C5H3Br2N/c6-4-1-2-5(7)8-3-4/h1-3H

Synthetic route

5-bromopyridin-2-ol (13466-38-1) → 2,5-dibromopyridine (624-28-2)

Conditions	Yield
With triphenylborane; phosphorus tribromide In 1,2-dichloro-ethane for 10h; Reagent/catalyst; Solvent; Inert atmosphere; Reflux;	88.7%
With phosphorus(V) oxybromide In acetonitrile at 80℃; for 21h; Reagent/catalyst; Temperature;	470 mg

5-bromo-2-pyridylamine (1072-97-5) → 2,5-dibromopyridine (624-28-2)

Conditions	Yield
Stage #1: 5-bromo-2-pyridylamine With hydrogen bromide; bromine In water at 0 - 20℃; for 0.166667h; Stage #2: With sodium nitrite In water at 0 - 5℃; for 0.5h;	87%
With tert.-butylnitrite; trimethylbenzylammonium bromide; 1,2-dibromomethane at 20℃;	83%
With tert.-butylnitrite; trimethylbenzylammonium bromide In 1,2-dibromomethane at 20℃;	83%

2-bromo-pyridine (109-04-6) → 2,5-dibromopyridine (624-28-2) + 2,3,5-tribromopyridine (75806-85-8)

Conditions	Yield
With bromine at 300℃; Leiten ueber mit Eisen(II)-bromid impraegnierten Bimsstein;

3-Bromopyridine (626-55-1) → 2,5-dibromopyridine (624-28-2) + 2,3,6-tribromopyridine (2402-92-8)

Conditions	Yield
With bromine at 500℃; Leiten ueber Bimsstein;

1-methyl-2-pyridone (694-85-9) + phosphorus pentabromide (7789-69-7) → 2,5-dibromopyridine (624-28-2)

Conditions	Yield
at 140 - 150℃;

diazotized 5-bromo-2-amino-pyridine → 2,5-dibromopyridine (624-28-2)

Conditions	Yield
With hydrogen bromide

N-methyl-α-pyridone → 2-bromo-pyridine (109-04-6) + 2,5-dibromopyridine (624-28-2)

Conditions	Yield
With phosphorus pentabromide; phosphorus(V) oxybromide at 120 - 130℃;
With phosphorus pentabromide at 140 - 150℃;

3-Bromopyridine (626-55-1) + bromine (7726-95-6) + pumice stone → 2,5-dibromopyridine (624-28-2) + 2,3,6-tribromopyridine (2402-92-8)

Conditions	Yield
at 500℃;

2-bromo-pyridine (109-04-6) + bromine (7726-95-6) + iron (II)-bromide → 2,5-dibromopyridine (624-28-2) + 2,3,5-tribromopyridine (75806-85-8)

Conditions	Yield
at 300℃;

2-aminopyridine (504-29-0) → 2,5-dibromopyridine (624-28-2)

Conditions	Yield
Multi-step reaction with 2 steps 1: ethanol; bromine / <20 2: bromine; aqueous hydrobromic acid / anschliessend Behandeln mit wss. Natriumnitrit-Loesung unterhalb von 0grad View Scheme
Multi-step reaction with 2 steps 1: N-Bromosuccinimide; ammonium acetate / acetonitrile / 0.08 h / 20 °C 2: tert.-butylnitrite; trimethylbenzylammonium bromide; 1,2-dibromomethane / 20 °C View Scheme
Multi-step reaction with 2 steps 1: N-Bromosuccinimide; ammonium acetate / acetonitrile / 0.08 h / 20 °C 2: tert.-butylnitrite; trimethylbenzylammonium bromide / 1,2-dibromomethane / 20 °C View Scheme

6-hydroxy-4-methoxymethyl-β-carboline-3-carboxylic acid ethyl ester (96136-88-8) → 2,5-dibromopyridine (624-28-2) + 6-(5-bromo-2-pyridyloxy)-4-methoxymethyl-β-carboline-3-carboxylic acid ethyl ester (111110-50-0)

(2-hydroxyethyl)(methyl)amine (109-83-1) + 2,5-dibromopyridine (624-28-2) → 2-[(5-bromopyridin-2-yl)methylamino]ethanol (149806-47-3)

Conditions	Yield
at 150℃; for 18h;	100%
potassium fluoride on basic alumina for 0.25h; microwave irradiation;	86%

2,5-dibromopyridine (624-28-2) + Na(1+)*((CH3)3SiCC)4Al(1-) → 3-bromo-6-(trimethylsilylethynyl)pyridine (111770-80-0)

Conditions	Yield
With bis-triphenylphosphine-palladium(II) chloride for 12h; Heating;	100%

2,5-dibromopyridine (624-28-2) + dimethyl(hept-1-yn-1-yl)aluminum → 2,5-di-hept-1-ynyl-pyridine

Conditions	Yield
With tris(dibenzylideneacetone)dipalladium(0) chloroform complex; 1,1'-bis-(diphenylphosphino)ferrocene In 1,2-dimethoxyethane; n-heptane at 85℃; for 1h;	100%

2,5-dibromopyridine (624-28-2) + dimethyl-pyrrolidin-3-yl-amine (69478-75-7, 108138-38-1, 132883-44-4, 132958-72-6) → [1-(5-bromo-pyridin-2-yl)-pyrrolidin-3-yl]-dimethyl-amine (690264-82-5)

Conditions	Yield
With 1,8-diazabicyclo[5.4.0]undec-7-ene In N,N-dimethyl-formamide at 250℃; for 0.5h; Microwave irradiation;	100%
With toluene-4-sulfonic acid In water at 140℃; for 14h;	96%
With toluene-4-sulfonic acid at 130℃;

2,5-dibromopyridine (624-28-2) + 3,4-dichlorophenol (95-77-2) → 5-bromo-2-(3,4-dichloro-phenoxy)-pyridine (99902-96-2)

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 90℃; for 18h;	100%

2,5-dibromopyridine (624-28-2) + (tert-butyldimethylsilyl)acetylene (86318-61-8) → 2-(tert-butyldimethylsilylethynyl)-5-bromopyridine (866929-82-0)

Conditions	Yield
With triethylamine; bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide In tetrahydrofuran at -7 - 20℃; for 4h;	100%
With triethylamine; bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide; N,N`-dimethylethylenediamine In tetrahydrofuran at -7 - 20℃; for 4h;	100%
With triethylamine; bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide In tetrahydrofuran at -7 - 20℃; for 4h;	100%

2,5-dibromopyridine (624-28-2) + cyclopropylzinc chloride (203861-73-8) → 3-bromo-6-(cyclopropyl)pyridine (579475-29-9)

Conditions	Yield
tetrakis(triphenylphosphine) palladium(0) In tetrahydrofuran at 70℃; for 3h;	100%
tetrakis(triphenylphosphine) palladium(0) In tetrahydrofuran at 70℃; for 1.5h;

2,5-dibromopyridine (624-28-2) + (3,3-dimethylbut-1-yn-1-yl)dimethylsilane (87290-98-0) → 2-(tert-butyldimethylsilylethynyl)-5-bromopyridine (866929-82-0)

Conditions	Yield
With triethylamine; bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide In tetrahydrofuran at -7 - 20℃; for 4h;	100%

2,5-dibromopyridine (624-28-2) + N,N-dimethyl acetamide (127-19-5) → 1-(5-bromopyridin-2-yl)ethanone (214701-49-2)

Conditions	Yield
With n-butyllithium In hexane; toluene at -40 - 20℃; for 2h; Inert atmosphere;	100%
Stage #1: 2,5-dibromopyridine With n-butyllithium In hexane; toluene at -40℃; for 0.666667h; Stage #2: N,N-dimethyl acetamide In hexane; toluene at 20℃; for 1h; Further stages.;	83%
Stage #1: 2,5-dibromopyridine With n-butyllithium In toluene Inert atmosphere; Stage #2: N,N-dimethyl acetamide In toluene Inert atmosphere;	83%

2,5-dibromopyridine (624-28-2) + methylamine (74-89-5) → 5-bromo-N-methylpyridin-2-amine (84539-30-0)

Conditions	Yield
In ethanol at 80℃; for 24h;	100%
In ethanol at 80℃; for 72h;	1.20 g
In methanol Autoclave; Large scale;

2,5-dibromopyridine (624-28-2) + 1-tert-butoxycarbonyl-4-cyanopiperidine (91419-52-2) → tert-butyl 4-(5-bromopyridin-2-yl)-4-cyanopiperidine-1-carboxylate (1196973-42-8)

Conditions	Yield
With lithium hexamethyldisilazane In toluene at 20℃; for 16h; Inert atmosphere;	100%

2,5-dibromopyridine (624-28-2) + 3-fluorophenol (372-20-3) → 5-bromo-2-(3-fluorophenoxy)pyridine (936343-48-5)

Conditions	Yield
Stage #1: 3-fluorophenol With sodium hydride In N,N-dimethyl-formamide at 0℃; for 0.166667h; Stage #2: 2,5-dibromopyridine In N,N-dimethyl-formamide at 0 - 110℃; for 7.75h;	100%
With potassium carbonate In N,N-dimethyl-formamide for 12h; Reflux; Large scale;	85%

morpholine (110-91-8) + 2,5-dibromopyridine (624-28-2) → 5-bromo-2-(4-morpholinyl)pyridine (200064-11-5)

Conditions	Yield
With 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; sodium t-butanolate; tris(dibenzylideneacetone)dipalladium (0) In toluene at 100℃; for 3h;	99%
at 120℃; for 1.66667h; microwave;	99.7%
With potassium fluoride on basic alumina; dichlorobis(tri-O-tolylphosphine)palladium at 90 - 100℃; for 5h;	92%

2,5-dibromopyridine (624-28-2) + benzyl alcohol (100-51-6) → 2-(benzyloxy)-5-bromopyridine (83664-33-9)

Conditions	Yield
With dibenzo-18-crown-6 In toluene for 3h; Heating;	99%
Stage #1: benzyl alcohol With sodium hydride In N,N-dimethyl-formamide; mineral oil at 20℃; for 0.5h; Cooling with ice; Stage #2: 2,5-dibromopyridine In N,N-dimethyl-formamide; mineral oil for 5h; Stage #3: With acetic acid In N,N-dimethyl-formamide; mineral oil at 0℃; for 0.5h;	99%
With potassium hydroxide; dibenzo-18-crown-6 In toluene for 1.5h; Heating / reflux;	92%

1-methyl-piperazine (109-01-3) + 2,5-dibromopyridine (624-28-2) → 1-N-(5-bromopyridin-2-yl)-4-methylpiperazine (364794-58-1)

Conditions	Yield
With 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; sodium t-butanolate; tris(dibenzylideneacetone)dipalladium (0) In toluene at 100℃; for 3h;	99%
In butan-1-ol for 96h; Reflux;	70%
With sodium hydrogencarbonate	67.1%

2,5-dibromopyridine (624-28-2) + 1-t-Butoxycarbonylpiperazine (57260-71-6) → 5-Bromo-2-(4-tert-butoxycarbonylpiperazin-1-yl)pyridine (153747-97-8)

Conditions	Yield
With 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; sodium t-butanolate; tris(dibenzylideneacetone)dipalladium (0) In toluene at 100℃; for 3h;	99%
With tris-(dibenzylideneacetone)dipalladium(0); 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; sodium t-butanolate In toluene at 80℃; for 4h; Sealed tube; Inert atmosphere;	82%
With pyridine at 125℃; for 12h;	39.5%
With potassium carbonate In dimethyl sulfoxide at 150℃; for 21h;

2,5-dibromopyridine (624-28-2) + methanol (67-56-1) + carbon monoxide (201230-82-2) → dimethyl 2,5-pyridine dicarboxylate (881-86-7)

Conditions	Yield
With dichloro[2,2'-bis(diphenylphosphino)-1,1'-binaphthyl]palladium(II); triethylamine at 100℃; under 2585.74 Torr; for 1h;	99%

2,5-dibromopyridine (624-28-2) + bromobenzene (108-86-1) → 5-bromo-2-phenylpyridine (27012-25-5)

Conditions

Yield

Stage #1: bromobenzene With n-butyllithium In tetrahydrofuran; hexane; cyclohexane at -78℃; for 0.5h; Inert atmosphere; Stage #2: With zinc(II) chloride In tetrahydrofuran; hexane; cyclohexane at -78 - 20℃; for 2.6h; Inert atmosphere; Stage #3: 2,5-dibromopyridine With tetrakis(triphenylphosphine) palladium(0) In tetrahydrofuran; hexane; cyclohexane for 16h; Negishi coupling reaction; Inert atmosphere; Reflux;

99%

2,5-dibromopyridine (624-28-2) + trimethylsilylacetylene (1066-54-2) → 3-bromo-6-(trimethylsilylethynyl)pyridine (111770-80-0)

Conditions	Yield
With triethylamine; copper(l) iodide; tetrakis(triphenylphosphine) palladium(0) In tetrahydrofuran at 17 - 30℃; for 0.5h; Sonogashira Coupling;	98%
With copper(l) iodide; palladium dichloride In triethylamine at 30℃; for 2.17h; Inert atmosphere;	97%
With copper(l) iodide; tetrakis(triphenylphosphine) palladium(0); triethylamine In tetrahydrofuran at 20℃; Sonogashira cross-coupling; Inert atmosphere;	92%

2,5-dibromopyridine (624-28-2) + ethylenediamine (107-15-3) → N1-(5-bromopyridin-2-yl)ethane-1,2-diamine (199522-66-2)

Conditions	Yield
at 100℃; for 15h;	98%
at 100℃; for 15h;	98%
With pyridine for 18h; Heating;	71%
at 100℃; for 16h;

2,5-dibromopyridine (624-28-2) + methanol (67-56-1) → 2-methoxy-5-bromopyridine (13472-85-0)

Conditions	Yield
With sodium hydroxide for 5h; Reflux;	98%
With sodium In N,N-dimethyl-formamide at 80℃; for 1h; Substitution;	95%
With potassium tert-butylate In DMF (N,N-dimethyl-formamide) at 20℃; for 18h;
With sodium methylate In methanol for 0.5h; Reflux;

2,5-dibromopyridine (624-28-2) + 2,5-bis(2-ethylhexyloxy)benzene-1,4-diboronic acid (191917-63-2) → poly{2,5-pyridilene-co-1,4-[2,5-bis-(2-ethylhexyloxy)]phenylene}, AB copolymer, Mw: 12000, Mn: 7400, polydispersity: 2.46; monomer(s): 2,5-dibromopyridine, 1,4-[2,5-bis(2-ethylhexyloxy)]diboronic acid

Conditions	Yield
With tetrakis(triphenylphosphine) palladium(0); sodium carbonate In tetrahydrofuran; water at 70℃; for 60h; Heating;	98%

2,5-dibromopyridine (624-28-2) + Dimethyldisulphide (624-92-0) → 2-bromo-5-methylthiopyridine (134872-23-4)

Conditions	Yield
Stage #1: 2,5-dibromopyridine With n-butyllithium In diethyl ether at -78℃; Stage #2: Dimethyldisulphide In diethyl ether	98%
Stage #1: 2,5-dibromopyridine With n-butyllithium In diethyl ether; hexane at -78℃; for 1h; Stage #2: Dimethyldisulphide In diethyl ether; hexane at -78 - 0℃; for 2h; Further stages.;	94%
With hydrogenchloride; n-butyllithium In hexane	94%

piperidine (110-89-4) + 2,5-dibromopyridine (624-28-2) → 5'-bromo-3,4,5,6-tetrahydro-2H-[1,2']bipyridinyl (24255-95-6)

Conditions	Yield
With 4,5-bis(diphenylphos4,5-bis(diphenylphosphino)-9,9-dimethylxanthenephino)-9,9-dimethylxanthene; sodium t-butanolate; tris(dibenzylideneacetone)dipalladium (0) In toluene at 100℃; for 3h;	98%
at 80℃; for 96h;	94%
With copper(l) iodide; potassium carbonate at 80℃; for 2h;	92%
With copper(l) iodide; potassium carbonate; L-proline In dimethyl sulfoxide at 80℃; for 40h; Inert atmosphere;	28%
With copper(l) iodide; bis(benzonitrile)palladium(II) dichloride Sonogashira coupling;

4-methylpiperidin (626-58-4) + 2,5-dibromopyridine (624-28-2) → 1-N-(5-bromopyridin-2-yl)-4-methylpiperidine

Conditions	Yield
With 4,5-bis(diphenylphos4,5-bis(diphenylphosphino)-9,9-dimethylxanthenephino)-9,9-dimethylxanthene; sodium t-butanolate; tris(dibenzylideneacetone)dipalladium (0) In toluene at 100℃; for 3h;	98%

pyrrolidine (123-75-1) + 2,5-dibromopyridine (624-28-2) → 5-bromo-2-(pyrrolidin-1-yl)pyridine (210963-93-2)

Conditions	Yield
In butan-1-ol at 75℃; for 16h; sealed tube;	98%
at 110℃; for 1.5h;	55%
With bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide Sonogashira coupling;

2,5-dibromopyridine (624-28-2) + ethanolamine (141-43-5) → 2-[(5-bromopyridin-2-yl)amino]ethanol

Conditions	Yield
for 3h; Reflux;	98%
for 3h; Reflux;	98%
at 220 - 250℃; for 0.5h; Microwave irradiation;	95%
potassium fluoride on basic alumina for 0.25h; microwave irradiation;	85%

2,5-dibromopyridine (624-28-2) + tert-butyl 4-(hydroxymethyl)piperidin-1-carboxylate (123855-51-6) → tert-butyl 4-((5-bromopyridin-2-yloxy)methyl)piperidine-1-carboxylate (1010114-48-3)

Conditions	Yield
With sodium hydride In N,N-dimethyl-formamide at 20℃; for 3h; Temperature; Concentration;	98%
With sodium hydride In N,N-dimethyl-formamide; mineral oil at 0 - 80℃; for 5h;	87%
Stage #1: tert-butyl 4-(hydroxymethyl)piperidin-1-carboxylate With sodium hydride In dimethyl sulfoxide; mineral oil at 20 - 50℃; for 1.5h; Stage #2: 2,5-dibromopyridine In dimethyl sulfoxide; mineral oil at 20℃;	84%
With sodium hydride In N,N-dimethyl-formamide at 0 - 20℃; for 3h;	78%

2,5-dibromopyridine (624-28-2) + 2-bromo-9H-carbazole (3652-90-2) → 2-bromo-9-(5-bromopyridin-2-yl)-9H-carbazole

Conditions	Yield
With 1-methyl-1H-imidazole; copper(l) chloride; lithium tert-butoxide In toluene at 130℃; for 5h; Inert atmosphere;	98%
With 1-methyl-1H-imidazole; copper(l) chloride; lithium tert-butoxide In toluene at 130℃; for 5h; Ullmann Condensation; chemoselective reaction;	80%

2,5-dibromopyridine (624-28-2) + hex-1-yne (693-02-7) → 2,5-di-1-hexynylpyridine

Conditions	Yield
With bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide; triethylamine at 50℃; for 72h; Sonogashira coupling;	97%

Upstream product

• 626-55-1 3-Bromopyridine 
• 1692-15-5 4-pyridylboronic acid 
• 106047-32-9 2,5-bis(pyrid-4-yl)pyridine 
• 96136-88-8 6-hydroxy-4-methoxymethyl-β-carboline-3-carboxylic acid ethyl ester 
• 504-29-0 2-aminopyridine 
• 109-04-6 2-bromo-pyridine 
• 7726-95-6 bromine 
• 694-85-9 1-methyl-2-pyridone 
• 7789-69-7 phosphorus pentabromide 
• 1072-97-5 5-bromo-2-pyridylamine 
• 13466-38-1 5-bromopyridin-2-ol 

Downstream Products

• 55849-30-4 5-bromo-2-ethoxypyridine 
• 32666-95-8 [3-(5-bromo-[2]pyridyl)-3-phenyl-propyl]-dimethyl-amine 
• 15862-18-7 5,5'-dibromo-2,2'-dipyridyl 
• 51933-78-9 5-bromo-2-(methylsulfanyl)pyridine 
• 98626-93-8 5-bromo-2-isopropylsulfanyl-pyridine 
• 774-53-8 5-bromo-2,3′-bipyridine 
• 106047-33-0 5-bromo-2,4′-bipyridine 
• 139042-62-9 1-(6-bromopyridin-3-yl)ethan-1-ol 
• 111770-82-2 2-(5-bromopyridin-2-yl)-prop-2-yn-1-ol 
• 91891-74-6 5-bromo-2-(thiophen-2-yl)pyridine 
• 92993-40-3 2-(3-aminopropylamino)-5-bromopyridine 
• 128071-75-0 2-bromopyridine-3-carboxaldehyde 
• 111770-81-1 5-bromo-2-(hex-1-yn-1-yl)pyridine 
• 111770-80-0 3-bromo-6-(trimethylsilylethynyl)pyridine 

Relevant articles and documents

Synthetic method of medicinal raw material 2 and 5 - dibromopyridine

The invention relates to the technical field of preparation of dibromopyridine, and discloses a synthetic method of a pharmaceutical raw material 2 and 5 - dibromopyridine, which comprises S1: temperature rising, 2 -aminopyridine and acetic anhydride added into a four-port flask. S2: Cooling, Step S1 The raw material reaction was completely followed by a cooling treatment, followed by stirring by adding bromoethane, heating at a heating temperature of 30 - 60 (degree) C, heating time of 20 - 40 minutes, and stirring again to obtain a mixture A. S3: Monol Bromo. To the method, raw materials can be pre-mixed, so that the raw materials can be preliminarily reacted, the reaction B effect is improved, bubbles are generated after reaction, the next crystallization is facilitated, cost can be reduced through accurate control of temperature and raw materials in the process, and the method is safer and more reliable.

The difference in the CO2adsorption capacities of different functionalized pillar-layered metal-organic frameworks (MOFs)

The excessive use of fossil energy has caused the CO2concentration in the atmosphere to increase year by year. MOFs are ideal CO2adsorbents that can be used in CO2capture due to their excellent characteristics. Studies of the structure-activity relationship between the small structural differences in MOFs and the CO2adsorption capacities are helpful for the development of efficient MOF-based CO2adsorbents. Therefore, a series of pillar-layered MOFs with similar structural and different functional groups were designed and synthesized. The CO2adsorption tests were carried out at 273 K to explore the relationship between the small structural differences in MOFs caused by different functional groups and the CO2adsorption capacities. Significantly, compound6which contains a pyridazinyl group has a 30.9% increase in CO2adsorption capacity compared to compound1with no functionalized group.

Synthesis method of 2, 5-dibromopyridine

The invention belongs to the technical field of organic synthesis, and particularly relates to a synthesis method of 2, 5-dibromopyridine, and the method comprises the following steps: (1) adding 2-aminopyridine and acetic anhydride into a four-neck flask, refluxing, and completely reacting by thin-layer chromatography tracking; (2) when the temperature of the reaction solution in the step (1) isreduced to 20-25 DEG C, dropwise adding liquid bromine, reacting for 2-3 hours at 45-55 DEG C after completion of the dropwise adding, adding water into the system until all solids are dissolved, dropwise adding a sodium hydroxide solution, continuously reacting for 30-40 minutes when a large amount of precipitate is generated, and carrying out suction filtration, drying and recrystallization to obtain 2-amino-5-bromopyridine; and (3) adding the 2-amino-5-bromopyridine into a hydrogen bromide solution, dropwise adding a sodium nitrate solution in the presence of a catalytic amount of cuprous bromide, controlling the temperature to be -5 to15 DEG C, and reacting for 2-5 hours to obtain the 2, 5-dibromopyridine. The method has the beneficial effects of mild reaction conditions, high yield, accessible raw materials, lower cost and fewer product byproducts, reduces the composite load of later separation, and has industrial prospects.