Solution aqueous glycine

Action of nitrous acid. To a few ml. of 20% NaNO, solution add a few drops of cold dil. acetic acid. Pour the mixture into a cold aqueous solution of glycine, and note the brisk evolution of nitrogen. NH CH COOH -h HNO2 = HO CH2COOH + N + H O. Owing to the insolubility of cystine in acetic acid use a suspension in dU. acetic acid for this test. In each case care must be taken not to confuse the evolution of nitrogen with any possible thermal decomposition of the nitrous acid cf. footnote, p, 360). 

Copper salt, (a) Add aqueous copper acetate solution to an aqueous solution of glycine. Note the formation of a blue colour which is considerably deeper than the colour of the original copper acetate solution. On heating the solution, blue needles of the copper salt usually separate. 

An infinitesimal transfer of glycine from the sohd phase to the solution at constant temperature, pressure, and composition of solution results in a corresponding change dJ in the thermodynamic property J of the system composed of crystalline glycine and a 1-molal aqueous solution of glycine. The application of Equation (9.32) leads to the expression... 

TABLE 18.3. Partial Molar Volumes in Aqueous Solutions of Glycine... 

Garetz, B. A., Malic, J., Myerson, A. S., Polarization switching of crystal structure in the nonphotochemical light-induced nucleation of supersaturated aqueous glycine solutions. Phys. Rev. Lett. 2002, 89. 

The classic method of Ley and Winkler —dissolving freshly prepared cobalt(III) hydroxide oxide, CoO(OH), in an aqueous solution of glycine with heating—gives both products, with the mer isomer predominating (often this is the only isomer formed). 

Calculate the pH of a 0.10 M aqueous solution of glycine at 25°C. Hint You may need to take account of the autoionization of water.)... 

The amino acid species in Equation 15-17, which bears both a positive and a negative charge, is called a zwitterion. As shown by Equations 15-18 and 15-19, the zwitterion of glycine is stronger as an acid than as a base. Thus, an aqueous solution of glycine is somewhat acidic. 

S. D. Schwartz, Nonequilibrium solvation and the Quantum Kramers problem proton transfer in aqueous glycine, /. Phys. Chem. B (Bill Miller festschrift), 105, 2563-2567 (2001) b) D. Antoniou, S. D. Schwartz, A Molecular Dynamics Quantum Kramers Study of Proton Transfer in Solution, /. Chem. Phys., 110, 465-472 (1999) c) D. Antoniou, S. D. Schwartz, Quantum Proton Transfer with Spatially Dependent Friction ... 

Sun, X., Garetz, B.A., Myerson, A.Y Supersaturation and polarization dependence of polymorph control in the nontopochemical laser-induced nucleation (NPLIN) of aqueous glycine solutions, Crystal Growth and Design. 1 (2001) 5-8. 

Aber, J.E., Arnold, S., Garetz, B.A, Myerson, AS. Strong dc electric field applied to supersaturated aqueous glycine solution induces nucleation of the y-polymorph, Phys. Rev. Lett. 94 (2005) 145503-5. 

Twenty-five milliliters of a 0.1-M aqueous solution of glycine is to be titrated with a O.l-M sodium hydroxide solution. Determine the pH of the solution, the fraction of glycine in the GH, GH, and G ionization states, and the charge on glycine as a function of the amount of sodium hydroxide added. 

Figure 1.23 Viscosity of aqueous glycine solution at 25 °C. (Reproduced from R.M. Ginde and A.S. Myerson (1991), Viscosity and Diffusivity in Metastable Solutions, AlChE Symposium Series, vol. 87, no. 284, pp. 124-129. Used by permission of the American Institute of Chemical Engineers. 1991 AIChE.)...

Figure 1.24 Diffusion coefficients of aqueous glycine solutions at 25, 35, and 45 °C. (Data from Chang 1984.)...

Figure 1.25 Diffusion coefficients in aqueous glycine solutions at 25 °C as a function of concentration and solution age. (Reproduced with permission from Myerson and Lo 1991.)...

Duval (1956) has studied the spectra of amino acids recorded from a single drop of aqueous solution. Parker and Kirschenbaum (1960) have recorded the spectra of several a- and non-a-amino acids in water. The spectra of aqueous solutions of glycine, N-methylglycine (sarcosine), yV,yV-dimethylglycine, and yV,yV,A(-trimethylglycine (betaine) in dilferent states of ionization have also been recorded (Kirschenbaum, 1963). Another solvent which has been suggested for infrared spectral determination of amino acids is antimony trichloride (Lacher et al., 1954). 

H2N —CH2—COOH +H3N —CH2—COO What assumptions did you need to make (b) What is the pH of a 0.050 M aqueous solution of glycine (c) What would be the predominant form of glycine in a solution with pH 13 With pH 1 ... 

Fig. 10.1 The structure of molecular iodine and triiodide complexes in an aqueous glycine-KI-l2 solution. Color code blue balls—carbon atoms, dark blue balls—nitrogen atoms, red balls— oxygen atoms, violet balls—iodine atoms...

The small difference in the Gibbs free energy (AG = G(Ia) — G(IIa) = —4.77 within B3PW91/midi approximation, and -3.55 kcal/mol value obtained within COSMO approach) for the complexes la and Ha makes it possible to assume that these two complexes can be detected by UV and IR methods in an aqueous solution of glycine-Kl3 mixmre. 

In the IR spectra of the aqueous solution of glycine-KI-l2 in the range of 1600-1300 cm the intensive absorption bands at 1580, 1497 and 1407 cm , 1322 cm are observed. The symmetric and antisymmetric deformation vibrations of NHj and symmetric and antisymmetric vibrations of the carboxyl group make a contribution at 1580, and 1497 cm . The bands at 1407, and 1322 cm may be attributed to the symmetric valence vibration of the carboxyl group. 

When comparing the experimental vibrational frequencies of the aqueous glycine solution and the aqueous solution of the system glycine-KI-l2 as discussed in [21], it was noted that the coordination of the carboxyl group with molecular iodine results in the reduction of the valence vibration frequency of the carboxyl group (from 1332 to 1322 cm ). As can be seen from Table 10.3, no shift to the short-wave region in the lib complex is observed. The band at 1322 cm is wider than the bands at 1580 and 1497 cm , therefore the vibrational frequencies of the... 

The UV spectrum of the system (c) is presented and discussed in [21]. In the UV spectmm of the aqueous glycine-KIs-LiCl-ethanol solution it is possible to distinguish three fairly broad bands at 212-257 nm, 257-319 nm, 320-380 nm. 

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