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How can I perform a reaction of conversion of benzoic acid to...
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Jay T Arnott
How can I perform a reaction of conversion of benzoic acid to...
TLC can be monitored by adding some reaction mass to Methanol or Isopropyl alcohol, then acid chloride converts spontaneously to its corresponding ester which is easily visible under UV irradiation with clear separation. Make sure that mass transfer must be under moisture free conditions
TLC can be monitored by adding some reaction mass to Methanol or Isopropyl alcohol, then acid chloride converts spontaneously to its corresponding ester which is easily visible under UV irradiation with clear separation. Make sure that mass transfer must be under moisture free conditions
benzoic acid + thionyl chloride without any solvent then reflux to convert all benzoic acid to benzoyl choride, you can follow up by TLC in Hexan:ethylacetate (5:1) good luck
benzoic acid + thionyl chloride without any solvent then reflux to convert all benzoic acid to benzoyl choride, you can follow up by TLC in Hexan:ethylacetate (5:1) good luck
Do you have a microwave cavity on hand? Then you can monitor the reaction with a FTIR with ATR unit, like we published in Real time observation of microwave-enhanced reactions via fast FTIR spectroscopy Heller, Eberhard; Lautenschläger, Werner; Holzgrabe, Ulrike Tetrahedron Letters (2009), 50(12), 1321-1323. The procedure is easy. You take 1 drop to a weflon plate, irratiate it until all the thionyl chloride is vaporized and then you measure an IR. The absence of the OH signal shows you the end of the reaction. This method is very quick, but it will work only when your product do not vaporize, too.
Do you have a microwave cavity on hand? Then you can monitor the reaction with a FTIR with ATR unit, like we published in Real time observation of microwave-enhanced reactions via fast FTIR spectroscopy Heller, Eberhard; Lautenschläger, Werner; Holzgrabe, Ulrike Tetrahedron Letters (2009), 50(12), 1321-1323. The procedure is easy. You take 1 drop to a weflon plate, irratiate it until all the thionyl chloride is vaporized and then you measure an IR. The absence of the OH signal shows you the end of the reaction. This method is very quick, but it will work only when your product do not vaporize, too.
I agree with Pratima but I'd run the reaction in presence of pyridine to quench the acid formed and to activate the thionyl chloride. For the monitoring I would suggest a TLC.
I agree with Pratima but I'd run the reaction in presence of pyridine to quench the acid formed and to activate the thionyl chloride. For the monitoring I would suggest a TLC.
One equivalent ofbenzoic acid in aprotic sovent (benzene/dichloromethane etc.)was refluxed for 3-4hrs in the presence of 3-4 equivalent thionyl chlorie. After completion of the reaction , solvent was removed and little of residue was dissolved in organic solvent to monitor the TLC, comparing with benzoic acid. When compound was found pure on TLC then whole material was dissolved in organic solvent, filtered and evaporated the solvent to obtain pur material.For further purification it was distilled under reduced pressure.
One equivalent ofbenzoic acid in aprotic sovent (benzene/dichloromethane etc.)was refluxed for 3-4hrs in the presence of 3-4 equivalent thionyl chlorie. After completion of the reaction , solvent was removed and little of residue was dissolved in organic solvent to monitor the TLC, comparing with benzoic acid. When compound was found pure on TLC then whole material was dissolved in organic solvent, filtered and evaporated the solvent to obtain pur material.For further purification it was distilled under reduced pressure.
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
Agree with Chandra Kanth P. For synthesis : Take atleast 5 Volume of dry DCM as a solvent followed by addition of 1.2-1.3 mol eq of Triethylamine. Cool the mass to -15 to -10°C under nitrogen atmosphere and add 1.1 mol eq of Thionyl chloride in 20-30 minutes. Raise temperature to 0°C and stir for 30-60 minutes. You can directly use this mixture for further use. But keep it in cold room don't allow to contaminate it with moisture or air.
TLC : Mobile phase Hexane:Ethyl acetate (8:2) with 0.1-0.2 ml of methanol and spot direct reaction mass or take reaction mass in 1 ml of MDC and add 0.5 ml Methanol and shake well for 2-3 minutes. Add water (1.0 mL) and spot with bottom MDC layer (At this time mobile phase will be hexane:Ethyl acetate 8:2 only). You will get your product in the form of an ester.
Agree with Chandra Kanth P. For synthesis : Take atleast 5 Volume of dry DCM as a solvent followed by addition of 1.2-1.3 mol eq of Triethylamine. Cool the mass to -15 to -10°C under nitrogen atmosphere and add 1.1 mol eq of Thionyl chloride in 20-30 minutes. Raise temperature to 0°C and stir for 30-60 minutes. You can directly use this mixture for further use. But keep it in cold room don't allow to contaminate it with moisture or air.
TLC : Mobile phase Hexane:Ethyl acetate (8:2) with 0.1-0.2 ml of methanol and spot direct reaction mass or take reaction mass in 1 ml of MDC and add 0.5 ml Methanol and shake well for 2-3 minutes. Add water (1.0 mL) and spot with bottom MDC layer (At this time mobile phase will be hexane:Ethyl acetate 8:2 only). You will get your product in the form of an ester.
thanks all for your valuable suggestions . I would also like to know the TLC pattern (acc to me benzoyl chloride is less polar as compared to benzoic acid , so the spot of benzoyl chloride will be formed at higher rf value ).
thanks all for your valuable suggestions . I would also like to know the TLC pattern (acc to me benzoyl chloride is less polar as compared to benzoic acid , so the spot of benzoyl chloride will be formed at higher rf value ).
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
TLC can be monitored by adding some reaction mass to Methanol or Isopropyl alcohol, then acid chloride converts spontaneously to its corresponding ester which is easily visible under UV irradiation with clear separation. Make sure that mass transfer must be under moisture free conditions
TLC can be monitored by adding some reaction mass to Methanol or Isopropyl alcohol, then acid chloride converts spontaneously to its corresponding ester which is easily visible under UV irradiation with clear separation. Make sure that mass transfer must be under moisture free conditions
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benzoic acid + thionyl chloride without any solvent then reflux to convert all benzoic acid to benzoyl choride, you can follow up by TLC in Hexan:ethylacetate (5:1)
good luck
benzoic acid + thionyl chloride without any solvent then reflux to convert all benzoic acid to benzoyl choride, you can follow up by TLC in Hexan:ethylacetate (5:1)
good luck
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Do you have a microwave cavity on hand? Then you can monitor the reaction with a FTIR with ATR unit, like we published in
Real time observation of microwave-enhanced reactions via fast FTIR spectroscopy
Heller, Eberhard; Lautenschläger, Werner; Holzgrabe, Ulrike
Tetrahedron Letters (2009), 50(12), 1321-1323.
The procedure is easy. You take 1 drop to a weflon plate, irratiate it until all the thionyl chloride is vaporized and then you measure an IR. The absence of the OH signal shows you the end of the reaction. This method is very quick, but it will work only when your product do not vaporize, too.
Do you have a microwave cavity on hand? Then you can monitor the reaction with a FTIR with ATR unit, like we published in
Real time observation of microwave-enhanced reactions via fast FTIR spectroscopy
Heller, Eberhard; Lautenschläger, Werner; Holzgrabe, Ulrike
Tetrahedron Letters (2009), 50(12), 1321-1323.
The procedure is easy. You take 1 drop to a weflon plate, irratiate it until all the thionyl chloride is vaporized and then you measure an IR. The absence of the OH signal shows you the end of the reaction. This method is very quick, but it will work only when your product do not vaporize, too.
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VOTE
I agree with Pratima but I'd run the reaction in presence of pyridine to quench the acid formed and to activate the thionyl chloride. For the monitoring I would suggest a TLC.
I agree with Pratima but I'd run the reaction in presence of pyridine to quench the acid formed and to activate the thionyl chloride. For the monitoring I would suggest a TLC.
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VOTE
The conversion of acid into acyl chloride viscus liquid is gerenal reaction the procedure is available in A.I.Vogel,s book .
The conversion of acid into acyl chloride viscus liquid is gerenal reaction the procedure is available in A.I.Vogel,s book .
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One equivalent ofbenzoic acid in aprotic sovent (benzene/dichloromethane etc.)was refluxed for 3-4hrs in the presence of 3-4 equivalent thionyl chlorie. After completion of the reaction , solvent was removed and little of residue was dissolved in organic solvent to monitor the TLC, comparing with benzoic acid. When compound was found pure on TLC then whole material was dissolved in organic solvent, filtered and evaporated the solvent to obtain pur material.For further purification it was distilled under reduced pressure.
One equivalent ofbenzoic acid in aprotic sovent (benzene/dichloromethane etc.)was refluxed for 3-4hrs in the presence of 3-4 equivalent thionyl chlorie. After completion of the reaction , solvent was removed and little of residue was dissolved in organic solvent to monitor the TLC, comparing with benzoic acid. When compound was found pure on TLC then whole material was dissolved in organic solvent, filtered and evaporated the solvent to obtain pur material.For further purification it was distilled under reduced pressure.
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VOTE
The conversion of acid into acyl chloride viscus liquid is gerenal reaction the procedure is available in A.I.Vogel,s book .
The conversion of acid into acyl chloride viscus liquid is gerenal reaction the procedure is available in A.I.Vogel,s book .
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VOTE
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
More
VOTE
Agree with Chandra Kanth P.
For synthesis : Take atleast 5 Volume of dry DCM as a solvent followed by addition of 1.2-1.3 mol eq of Triethylamine. Cool the mass to -15 to -10°C under nitrogen atmosphere and add 1.1 mol eq of Thionyl chloride in 20-30 minutes. Raise temperature to 0°C and stir for 30-60 minutes. You can directly use this mixture for further use. But keep it in cold room don't allow to contaminate it with moisture or air.
TLC : Mobile phase Hexane:Ethyl acetate (8:2) with 0.1-0.2 ml of methanol and spot direct reaction mass or take reaction mass in 1 ml of MDC and add 0.5 ml Methanol and shake well for 2-3 minutes. Add water (1.0 mL) and spot with bottom MDC layer (At this time mobile phase will be hexane:Ethyl acetate 8:2 only). You will get your product in the form of an ester.
Agree with Chandra Kanth P.
For synthesis : Take atleast 5 Volume of dry DCM as a solvent followed by addition of 1.2-1.3 mol eq of Triethylamine. Cool the mass to -15 to -10°C under nitrogen atmosphere and add 1.1 mol eq of Thionyl chloride in 20-30 minutes. Raise temperature to 0°C and stir for 30-60 minutes. You can directly use this mixture for further use. But keep it in cold room don't allow to contaminate it with moisture or air.
TLC : Mobile phase Hexane:Ethyl acetate (8:2) with 0.1-0.2 ml of methanol and spot direct reaction mass or take reaction mass in 1 ml of MDC and add 0.5 ml Methanol and shake well for 2-3 minutes. Add water (1.0 mL) and spot with bottom MDC layer (At this time mobile phase will be hexane:Ethyl acetate 8:2 only). You will get your product in the form of an ester.
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thanks all for your valuable suggestions . I would also like to know the TLC pattern (acc to me benzoyl chloride is less polar as compared to benzoic acid , so the spot of benzoyl chloride will be formed at higher rf value ).
thanks all for your valuable suggestions . I would also like to know the TLC pattern (acc to me benzoyl chloride is less polar as compared to benzoic acid , so the spot of benzoyl chloride will be formed at higher rf value ).
More
VOTE
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
One can not monitor this reaction on TLC! Hydrolysis of the acid chloride either by moisture on plate or solvent or air will give back the acid. If it is a small scale reaction, IR would be useful tool to monitor. For large scale reaction, a paraffin bubbler indicating the evolution of sulfur dioxide gas is most convenient.
More
VOTE
Tlc would be easy, strongly UV+. Plenty of great suggestion. But why do you bother using Thionyl Chloride, it is not what we can call a friendly reagent to use/handle/dispose. Benzoyl Cl is cheap as chips these days: 1L/300AUD!
http://www.sigmaaldrich.com/catalog/search?interface=All&term=Benzoyl%20cl&N=0&focus=product&lang=en®ion=AU
Tlc would be easy, strongly UV+. Plenty of great suggestion. But why do you bother using Thionyl Chloride, it is not what we can call a friendly reagent to use/handle/dispose. Benzoyl Cl is cheap as chips these days: 1L/300AUD!
http://www.sigmaaldrich.com/catalog/search?interface=All&term=Benzoyl%20cl&N=0&focus=product&lang=en®ion=AU
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