NOVELTY - 3-(p-Toluenesulfonyl)pyridine is added to sodium hydroxide solution, dimethyl sulfide is added, and extracted with diethyl ether to obtain 3-aminopyridine. 3-Aminopyridine is added to reactor, palladium on carbon catalyst is added, filtered, hydrochloric acid is added to the filtrate, and dried to obtain 3-methylaminopiperidine dihydrochloride. Boron diethyl-1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylate, 3-methylaminopiperidine dihydrochloride, triethylamine and ionic liquid are added and reacted to obtain white powdery solid of balofloxacin dihydrate.    USE - Preparation of balofloxacin dihydrate (claimed).    ADVANTAGE - The method provides balofloxacin dihydrate having excellent catalytic effect by efficient and environmentally-friendly process.    DETAILED DESCRIPTION - Boric acid and acetic anhydride are added to reactor, stirred at 110-120 degrees C, acetic acid is added, stirred, cooled to 80 degrees C, diethyl-1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylate is added and stirred at 80-100 degrees C. The resulting mixture is distilled off under reduced pressure, obtained residue is poured into water, stirred, filtered, filter cake is washed with water and ethanol and vacuum-dried to obtain white solid of boron diethyl-1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylate. Pyridine and p-toluenesulfonyl chloride are added, stirred, 3-aminopyridine is added and reacted at constant temperature. The resulting mixture is poured into water to obtain 3-(p-toluenesulfonyl)pyridine crude product. The crude product is recrystallized using 80 vol.% ethanol to obtain needle-like crystals. 3-(p-Toluenesulfonyl)pyridine is added to sodium hydroxide solution, stirred at 60 degrees C, dimethyl sulfide is added, reacted at 60 degrees C, pH of the resulting mixture is adjusted to 12, filtered and washed with distilled water to obtain solids. The solid is dried and dried product is added to 80 %mass sulfuric acid solution, resulting mixture is diluted with water, aqueous ammonia is added, extracted with diethyl ether, ether layer is removed, dried using anhydrous magnesium sulfate and the remaining liquid is distilled to obtain 3-aminopyridine. 3-Aminopyridine is added to reactor, palladium on carbon catalyst and ethanol are added, nitrogen gas is passed to the resulting mixture, hydrogen gas is passed, stirred, reacted at 180-200 degrees C, cooled to 70 degrees C, and the resulting material is filtered. Hydrochloric acid is added to the filtrate, stirred, filtered and dried to obtain 3-methylaminopiperidine dihydrochloride. Boron diethyl-1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylate and 3-methylaminopiperidine dihydrochloride, triethylamine and ionic liquid are added to reactor, reacted at 50-60 degrees C for 6-8 hours, 25% sodium hydroxide solution is added, heated to 80 degrees C, and water is added to the resulting mixture. pH of the resulting mixture is adjusted to 9 using 20% acetic acid solution, stirred, filtered, filter cake is washed with water and ethyl acetate and vacuum-dried to obtain white powdery solid of balofloxacin dihydrate. The volume ratio of ethanol and water is 1:1.