Abstract: The present invention provides a process for the preparation of diphenic acid from phenanthrene which comprises heating phenanthrene and glacial acetic acid, adding drop-wise a pre-determined amount of 30% hydrogen peroxide, heating the resulting mixture after completion of drop wise addition of hydrogen peroxide, distilling the resulting mixture under reduced pressure to make the volume half, cooling the mixture till diphenic acid crystalises out, filtering the cooled mixture and boiling the residue after adding 10% solution of sodium carbonate and activated charcoal, filtering and discarding the residue; acidifying the filtrate with hydrogen chloride; cooling the resultant mixture till more diphenic acid crystallises out; repeating filtration till pure diphenic acid is obtained.

Abstract: The present invention relates to a system and a process for obtaining phenanthrene of about 95% purity from coal tar distilled fraction containing crude phenanthrene by performing fractional distillation at a reduced pressure of 50 mm mercury and at a temperature range of 160-180° C. to obtain first distilled fraction containing acenaphthene and fluorene; a second distillate fraction at a temperature range of 200-230° C. containing phenanthrene, anthracene and traces of carbazole; followed by re-distilling the second distillate fraction at a temperature range of 210-224° C. to finally obtain pure phenanthrene and a residue which is again used for the recovery of residual phenanthrene by re-distillation at a temperature range of 210-224° C.

Abstract: The present invention provides a process for the preparation of diphenic acid from phenanthrene which comprises heating phenanthrene and glacial acetic acid, adding drop-wise a pre-determined amount of 30% hydrogen peroxide, heating the resulting mixture after completion of drop wise addition of hydrogen peroxide, distilling the resulting mixture under reduced pressure to make the volume half, cooling the mixture till diphenic acid crystalises out, filtering the cooled mixture and boiling the residue after adding 10% solution of sodium carbonate and activated charcoal, filtering and discarding the residue; acidifying the filtrate with hydrogen chloride; cooling the resultant mixture till more diphenic acid crystallises out; repeating filtration till pure diphenic acid is obtained.

Abstract: The present invention relates to a system and a process for obtaining phenanthrene of about 95% purity from coal tar distilled fraction containing crude phenanthrene by performing fractional distillation at a reduced pressure of 50 mm mercury and at a temperature range of 160-180° C. to obtain first distilled fraction containing acenaphthene and fluorene; a second distillate fraction at a temperature range of 200-230° C. containing phenanthrene, anthracene and traces of carbazole; followed by re-distilling the second distillate fraction at a temperature range of 210-224° C. to finally obtain pure phenanthrene and a residue which is again used for the recovery of residual phenanthrene by re-distillation at a temperature range of 210-224° C.