In the present work the clathrate hydrate dissociation enthalpies of refrigerant R134a+ water system, and R134a + water + salt system were determined. The heat of dissociation of three types of aqueous salts solutions of NaCl, KBr and NaF at three concentrations (0.09, 0.17and 0.26) mol·kg⁻¹ for each salt type, were enthalpy measured. The Clapeyron equation was used tocalculate heat of dissociation of experimental data for binary and ternary system.In order to find the effect of compressibility factor on heat dissociation enthalpy, the study was conducted by using equation of state proposed by Peng and Robinson Stryjek-Vera (PRSV). The obtained results of dissociation enthalpy for binary system were (143.8) kJ.mol^-1

A simple UV spectrophotometric differential derivatization method was performed for the simultaneous quantification of three aromatic amino acids of tryptophan, the polar tyrosine and phenylalanine TRP, TYR and PHE respectively. The avoidance of the time and reagents consuming steps of sample preparation or analyze separation from its bulk of interferences made the approach environmentally benign, sustainable and green. The linear calibration curves of differential second derivative were built at the optimum wavelength for each analyze (218.9, 236.1 and 222.5 nm) for PHE, TRP and TYR respectively. Quantification for each analyze was in the concentration range of (1.0– 45, 0.1–20.0 and 1.0– 50.0 μg/ml) at replicates of (n=3) with a re

The  conductance  of  solu ti ons  of  cysteine  in  water  at  different concentrations and temperatures has been measured. These solutions obey Onsagcr  equation  and  give  linear  relations  especially  at  low concentrations. In more concentrated solutions a deviation from the equation is observed.

The molar conductivity of these solutions decreases with t he increase  in concen trations at constant temperature.

The  values of  the ionization constants and the conductivity at  infin ite

dilution for each temperature have been calcu lated.

In this work four complexes of antimony were prepared ,Na[SbO(gly)2],Na[SbO(Asp)2],Na[SbO(Tyrosin)2], Na [SbO(phen alanin)2]. by reaction SbOCl with salts amino acids identifiefid these complexes by FTIR ,their conductivity was measured and also their biological activity against two types of bacteria was studied ,they were biologically active.

This work contain many steps starting from esterification of isophthalic acid to yield diester compound [I] which was converted to their acid hydrazide [II], then the later compound reacted with ethylacetoacetate to yield pyrazol-5-one compound [III]. Afterword added acetyl chloride to give the compound [IV], thereaction of this compound with theiosemicarbazide ledto produce a new carbothioamide compound [V], Which was reacted with ethyl chloro acetate to yield thethioxoimidazolidin compound [VI]. The condensation reaction of this compound with different substituted aldehyde give new alkene derivatives[VII]a-d. The synthesized compounds were characterized by melting points , FT-IR ,1H-NMR and Mass spectroscopy .

In this paper a new series of morpholine derivatives was prepared by reacting the morpholine with ethyl chloro acetate in the presence triethylamine as a catalyst in benzene gave morpholin-N-ethyl acetate(1) which reacted with hydrazine hydrate in ethanol, and gave morpholin-N-ethyl acetohydrazide (2) . Morpholin-N-aceto semithiocarbazide (3) were prepared by reacting compound(2) with ammonium thiocyanate , concentrated hydrochloric acid and ethanol as a solvent .Compound (3) reacted with sodium hydroxide and hydrochloric acid to give 5-(morpholin-N-methylene)-1H-1,2,4-triazole-3-thiol (4) .The new series of 1,2,4-triazol derivatives (5-8) was synthesized by reaction of compound(4) with formaldehyde , DMF as a solvent and different

  In this study, Schiff's bases [S3,S4] were synthezied by condensation of N,N-dimethyl amino benzaldehyde with primary aromatic amine[N-(hydrazinyl methyl)benzamide]. These Sciff's bases were found to react with maleic anhydride and phthalic anhydride to give 1,3Oxazepine[S5,S6,S7,S8] in good yields.            The structures confired by m.p ,T.L.C.,FT.IR and 1H-NMR (of some of them).

In this paper the new starting material 2-(5-chloro-1H-benzo[d]imidazole-2-yl) aniline (1) was synthesized by the condensation reaction of 4-chloro-o-phenylenediamine and anthranilic acid .The new Mannich base derivatives were synthesized using formaldehyde and different secondary amines to synthesize a new set of benzimidazole derivatives(2-5). Also, the new Schiff-base derivatives (6-10) were synthesized from the reaction of compound (1) with various aromatic aldehydes and the closure-ring was done successfully using mercapto acetic acid to get the new thiazolidine derivatives(11-12).These new compounds were characterized using some physical techniques like:FT-IR Spectra and 1HNMR Spectra.

  A series of N- benzoyl  - 2 – alkyl -1- ( 2- thio – 1,3,4- thiadiazole -5- yl ) , have been synthesized from DL- α– amino acids , The methyl and sulfon thio ethers of these compounds were also prepared , representative samples of the prepared compounds were characterized from their IR- spectrum and elemental analysis .
 

Antiviral medications may be the best choices for COVID-19 treatment until particular therapeutic treatments become available. Tamiflu (oseltamivir) is a neuraminidase inhibitor licensed for the management and defense against influenza types A and B. Oseltamivir-based medication combinations are currently being used to treat COVID-19 patients who also have the new coronavirus 1 SARS-CoV-2. 1 Oseltamivir administration was related with a less time spent in the hospital, quicker recovery 1 and discharge, and a decreased mortality rate. Docking is a modern computational method for identifying a hit molecule by assessing the binding ability of molecular medicines within the binding target pocket. In this work, we chose 21 ligand compounds that