Mennuru,

You have good answers provided by colleagues, however I would like to be more precise:

For microwave assisted this reaction, see 

--- Gadhwal, Sunil et al Synlett, (10), 1573-1574; 1999

For using ionic liquid, see

--- Wang, Haibin et al, Synthetic Communications, 41(21), 3223-3227; 2011

" aromatic ketones (1.0 mmol), hydrazine hydrate (2.0 mmol), and ionic liquid

(5 mL)"  

For simple old easy way, see

--- http://orgsyn.org/demo.aspx?prep=CV3P0351

" Benzophenone hydrazone is most readily prepared from benzophenone (40 g., 0.22 mole) in 150 ml. of absolute ethanol with 41.2 g. (0.824 mole) of 100% hydrazine; the mixture is heated under reflux for 10 hours. On cooling in ice, colorless benzophenone hydrazone separates. The yield is 37.5 g. (87%), m.p. 97–98°. If anhydrous hydrazine is not available, it may be prepared by the method described in Org. Syntheses, 24, 53 (1944)."

It is clear that they have used excess N2H4-H2O

Good luck

The formation of benzophenone azine shows that your reaction in principle works. You just have to make sure that you always have an excess of hydrazine to prevent from azine formation. You can either use an excess of hydrazine or just slowly add benzophenone to the hydrazine solution. Maybe you cannot reach high yields but you can then seperate both compounds by column chromatography.

You can follow the below papers 

http://onlinelibrary.wiley.com/doi/10.1002/ps.3607/abstract

http://onlinelibrary.wiley.com/doi/10.1002/1526-4998(200102)57:2%3C191::AID-PS275%3E3.0.CO;2-O/abstract;jsessionid=EA7060B28E1C38FE47E40F2789C665FD.f02t03

Excess of hydrazine relative to benzophenone is necessary, simple green catalysis by Ce(III), see https://www.researchgate.net/publication/265959505_Synergism_of_Metal_and_Organocatalysis_in_Condensation_Reactions_of_Aromatic_Aldehydes_with_Anilines_Affording_Imines_Effect_of_Catalysts_on_the_Base_of_a_Supported_Cerium%28III%29_and_Proline?ev=prf_pub

Article Synergism of Metal and Organocatalysis in Condensation React...

I have tried a procedure by Shirinian and it works nicely with aromatic aldehydes and ketones by reflux with excess hydrazine hydrate and using p-toluene sulfonic acid as a catalyst in EtOH. The reaction proceeds selectively in over 95%  yield with high-purity products and without formation of azine.

Russian Chemical Bulletin, Vol. 48, No. I 1, November, 1999

 Mennuru,

You have good answers provided by colleagues, however I would like to be more precise:

For microwave assisted this reaction, see 

--- Gadhwal, Sunil et al Synlett, (10), 1573-1574; 1999

For using ionic liquid, see

--- Wang, Haibin et al, Synthetic Communications, 41(21), 3223-3227; 2011

" aromatic ketones (1.0 mmol), hydrazine hydrate (2.0 mmol), and ionic liquid

(5 mL)"  

For simple old easy way, see

--- http://orgsyn.org/demo.aspx?prep=CV3P0351

" Benzophenone hydrazone is most readily prepared from benzophenone (40 g., 0.22 mole) in 150 ml. of absolute ethanol with 41.2 g. (0.824 mole) of 100% hydrazine; the mixture is heated under reflux for 10 hours. On cooling in ice, colorless benzophenone hydrazone separates. The yield is 37.5 g. (87%), m.p. 97–98°. If anhydrous hydrazine is not available, it may be prepared by the method described in Org. Syntheses, 24, 53 (1944)."

It is clear that they have used excess N2H4-H2O

Good luck

Thanks to all for the valuable inputs, I have tried already few of the methods except the traditional old simple method of refluxing for about 10 hrs........ I will try that also.

Here I came to know about the other unique procedures to synthesize the hydrazone, which I will try to perform in the future.

Once again thank for all your support........will be grateful to all.

Hydrazine hydrate and polar liquid as methanol dried taken in microwave OR conventional method in lab and then after addition of Benzophenone calculated amt

A mixture of benzophone and hydrazine hydrate solution in ethanol was heated to reflux 24 h , the solvent was removed in vacuo and residue was recrystallized from ethanol,