Process for the synthesis of [6,6]-phenyl-C61butyric acid pentyl ester (PC61BP)

Patent metadata

Field	Value
Publication number	US-9676707-B2
Application number	US-201615047342-A
Country	US
Kind code	B2
Filing date	Feb 18, 2016
Priority date	Feb 18, 2015
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A total green, eco-friendly process for the synthesis of new acceptor molecule [6,6]-phenyl-C 61 -butyric acid pentyl ester (PC61BP) in high yields is carried under aerobic conditions showing better performance as acceptor in organic solar cells. More importantly this process causes the low cost synthesis of PC61BP in good yield without involving harmful and costly catalysts or chemicals.

First claim

We claim:

1. A process for the synthesis of [6,6]-phenyl(C 61 )butyric acid pentyl ester (PC61BP) of Formula 1, comprising the steps of:

i) reacting an organic acid ester and a p-toluene sulphonyl hydrazide in the range of 1:1.2 to 1:1.5 by dissolving the compounds in methanol and refluxing with stirring for 4-6 hrs followed by stirring at room temperature in the range of 20-30° C. for a period in the range of 10-12 hr and cooling at 0-10° C. to obtain organic acid ester hydrazone crystals;
ii) washing the hydrazone crystals as obtained in step (i) with cold methanol to obtain pure organic acid ester hydrazone;
iii) dissolving the organic acid ester hydrazone as obtained in step (ii) in an organic solvent and cooled to −10 to 10° C., followed by adding alkyl amine and stirring for a period in the range of 1-3 hrs to obtain an organic acid ester hydrazone solution;
iv) adding a fullerene solution to the organic acid ester hydrazone solution as obtained in step (iii) in the ratio ranging between 1:0.33-1:0.5 and temperature raised to 80-100° C. by continuous stirring for a period in the range of 18-24 hrs followed by precipitating with methanol to obtain a mixture;
v) centrifuging the mixture as obtained from step (iv) to obtain a solid;
vi) loading the solid as obtained in step (v) on a silica gel column and purifying it with toluene to obtain unreacted fullerene and monoadduct [5,6]PC61BP;
vii) refluxing the monoadduct as obtained in step (vi) in o-dichlorobenzene for a period in the range of 5-7 hrs followed by centrifuging to obtain [6,6]-phenyl(C 61 )butyric acid pentyl ester.

2. The process as claimed in claim 1 , wherein the organic acid ester is pentyl-4-benzoylbutyrate.

3. The process as claimed in claim 1 , wherein the organic acid ester hydrazone is pentyl-4-benzoylbutyrate p-tosylhydrazone.

4. The process as claimed in step (iii) of claim 1 , wherein the organic solvent used is ethyl acetate or dichloromethane.

5. The process as claimed in claim 1 , wherein diazomethane is generated insitu by using the organic acid ester hydrazone in the presence of triethylamine as base.

6. The process as claimed in claim 1 , wherein the alkyl amine used is selected from the group consisting of diethyl amine and diisopropyl amine.

7. The process as claimed in step (iv) of claim 1 , wherein fullerene solution is prepared using an organic solvent selected from the group consisting of o-dichlorobenzene and toluene.

Assignees

• Council Scient Ind Res

Inventors

• Kumar Rachana
• NAQVI Samya
• Gupta Neha
• Chand Suresh

Classifications

• C07C311/49

  to nitrogen atoms · CPC title

• C07C245/18

  the carbon skeleton being further substituted by carboxyl groups · CPC title

• C07C303/40 Primary

  by reactions not involving the formation of sulfonamide groups · CPC title

• C07C313/06

  Sulfinamides · CPC title

• C07C67/343

  by increase in the number of carbon atoms · CPC title