COMPARATIVE LOGARITHMIC PARTITION COEFFICIENT COMPARISON STUDY OF SYNTHESIZED HYDRAZINE AND PHENYL HYDRAZINE SERIES OF UREA, THIOUREA AND GUANIDINE TO FORM AMIDE AND LACTAM UNITS
Shouvik Sarkar*, Fatima Khatun, Arpita Biswas, Dr. Dhrubo Jyoti Sen and Dr. Beduin Mahanti
Partition coefficient of any compound shows the solubility profile of the compound in protic or aprotic solvent. In chemistry, a protic solvent is a solvent that has a hydrogen atom bound to oxygen (as in a hydroxyl group) or nitrogen (as in an amine group). In general terms, any solvent that contains a labile H+ is called a protic solvent. The molecules of such solvents readily donate protons (H+) to reagents. Conversely, aprotic solvents cannot donate hydrogen. Polar protic solvents are often used to dissolve salts. In general, these solvents have high dielectric constants and high polarity. Common characteristics of protic solvents: solvents display hydrogen bonding, solvents have acidic hydrogen (although they may be very weak acids such as ethanol), solvents dissolve salts, cations by unshared free electron pairs, anions by hydrogen bonding. Examples include water, most alcohols, formic acid, hydrogen fluoride, and ammonia. Polar protic solvents are favorable for SN1 reactions, while polar aprotic solvents are favorable for SN2 reactions. Polar aprotic solvents are solvents that lack acidic hydrogen. Consequently, they are not hydrogen bond donors. These solvents generally have intermediate dielectric constants and polarity. Although discouraging use of the term "polar aprotic", IUPAC describes such solvents as having both high dielectric constants and high dipole moments, an example being acetonitrile. Other solvents meeting IUPAC's criteria include DMF, HMPA, and DMSO. Common characteristics of aprotic solvents: solvents that can accept hydrogen bonds, solvents do not have acidic hydrogen, solvents dissolve salts. The criteria are relative and very qualitative. A range of acidities are recognized for aprotic solvents. Their ability to dissolve salts depends strongly on the nature of the salt. Polar aprotic solvents are generally incompatible with strong bases, such as Grignard reagents or n-butyllithium. These reagents require ethers, not nitriles, amides, sulfoxides, etc. In this project water (dielectric constant: 78.7F/m) and ethanol (dielectric constant: 24.3F/m) were taken as solvents for investigation of solubility during crystallization. Since water is more polar than ethanol so polar compounds dissolve faster in water than ethanol which gave a good result during purification of all compounds.
Keywords: Ethyl acetoacetate, Hydrazine, Phenyl hydrazine, Hydrogen peroxide, Potassium hydroxide, Potassium permanganate, Thionyl chloride, Urea, Thiourea, Guanidine.
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