INVESTIGATION OF THE CONSTITUTION AND STRUCTURE OF JIAWANG VITRINITES BY MILD HYDROGENATION——Ⅲ. STUDY ON THE COMPOSITION OF THE MILD HYDROGENATION PRODUCTS FROM JIAWANG VITRINITES BY UV AND IR SPECTROGRAPHY

INVESTIGATION OF THE CONSTITUTION AND STRUCTURE OF JIAWANG VITRINITES BY MILD HYDROGENATION——Ⅲ. STUDY ON THE COMPOSITION OF THE MILD HYDROGENATION PRODUCTS FROM JIAWANG VITRINITES BY UV AND IR SPECTROGRAPHY

The results of TG and IR analysis show that the formular of the complex is Zn(C_8H_8O_4)·2H_2O, and that the starting decomposion temperature of the complex is approximately 377 ℃ and the complete decomposion temperature 493 ℃ with the final decomposion product ZnO.

The result of the present experiment clarify the relation of radiation in the near IR spectrum of air with NO and N2 concentration and provide new experimental evidence for the NO hypothsis.

All of the new compounds were characterized by not only NMR, MS and IR spectra, but also the single-crystal X-ray analysis in the case of the product 3e.

The synthesized compounds have been characterized on the basis of elemental analyses, infrared spectroscopy (IR), and nuclear magnetic resonance (NMR).

Their structures were determined by IR spectra, 1H nuclear magnetic resonance (NMR), 13C NMR, and elemental analysis.

The polymers were characterized by IR spectra, thermal-weight analysis, scanning electron microscope and laser particle size analysis.

The structure of the B3 monomer was confirmed by MS, 1H NMR/IR.

The structure of the titled compound is determined by infrared spectrum(IR), proton nuclear magnetic resonance (HNMR), and mass spectrum (MS) and elemental analysis (EA).

The average nuclear level spacings of In, Ir and Au are estimated from the beta-ray activities induced by the primary photo-neutrons emitted from a Ra+Be source. A Geiger-Muller counter made of aluminum is used for measuring the induced activities. The saturated induced activities for the three elements are found to be 0.665±0.23 0.982±.03l, 0.453±0.21 (no./sec.) respectively. The estimation for the average nuclear level spacings is made in accordance with Breit-Wigner's one level formula, the resnlts...

The average nuclear level spacings of In, Ir and Au are estimated from the beta-ray activities induced by the primary photo-neutrons emitted from a Ra+Be source. A Geiger-Muller counter made of aluminum is used for measuring the induced activities. The saturated induced activities for the three elements are found to be 0.665±0.23 0.982±.03l, 0.453±0.21 (no./sec.) respectively. The estimation for the average nuclear level spacings is made in accordance with Breit-Wigner's one level formula, the resnlts being 5.6, 15 and 6 volts for In, Ir, Au respectively. The spacing of Ir is probably somewhat over estimated since the values of the energy and absorption coefficient of the resonance neutron group, used in the estimation, are not very accurate.

Theories of the "dead-stop" end-point method of titration of Foulk andBawden have been studied recently by Delahay, Kies, Duyckaerts,Gauguin and Charlot, and Bradbury, but no conclusive remarks have beenobtained by these authors as to the choice of optimum experimental conditionssuch as the applied voltage, the initial concentration of the solution to betitrated, the temperature, the electrode area, the stirring rate, the resistancein the circuit and the sensitivity of the galvanometer. This situation hashandicapped...

Theories of the "dead-stop" end-point method of titration of Foulk andBawden have been studied recently by Delahay, Kies, Duyckaerts,Gauguin and Charlot, and Bradbury, but no conclusive remarks have beenobtained by these authors as to the choice of optimum experimental conditionssuch as the applied voltage, the initial concentration of the solution to betitrated, the temperature, the electrode area, the stirring rate, the resistancein the circuit and the sensitivity of the galvanometer. This situation hashandicapped the wide applicability of this method, although it yields accurateresults and requires only inexpensive equipment. In the above mentioned theories, it is generally assumed that the iR dropin the circuit may be neglected i. e., the concentration overpotential E_πis equalto the applied voltage E and will not change in the course of the titration.But it is found experimentally that the magnitude of the resistance in thecircuit will greatly effect the shape of the titration curve and the sharpness ofthe end point. In fact, if we want to increase the sensitivity of the method(i. e., to titrate very dilute solutions), it is necessary to insert a high resistance(as high as a mega ohm) in the circuit in order to have a sharp end point In view of the above considerations we have derived the equations, g=i/i_0 =xSE~(-1)(Y_B-1)/(Y_B+1), 0≤x<0.5 (1a) g=0.5SE~(-1)(Y~(1/2)-1)/(Y~(1/2)+1) x=0.5 (1b) g=(1-x)SE~(-1)(Y_A-1)/(Y_A+1), 0.51 (1e)for the intensity of current i as a function of the "fraction x being titrated"(at the end point, x=1) during the titration of A with D as shown by thefollowing reaction: A+D=B+C (2)where A/B and C/D are two reversible redox pairs. In these equations, g=the ratio of the current i at any given stage during the titrationto that i_0 which would be obtained if the concentration overpotential E_π were zero. This latter quantity is equal to the applied voltage E divided by thetotal resistance R in the circuit, i. e., i_0=E/R. S="the dead-stop titration constant" which determines the shape ofthe titration curve and is equal to the product of three quantities: 1) thediffusion current constant of A, k_A, 2) the initial concentration of A, C_0, 3)the total resistance, R; i. e., S = k_AC_0R. K=the equilibrium constant of the reaction (2). α=the ratio of the diffusion current constant of D to that of A, i. e.,α=k_D/k_A. Y_A=the ratio of the concentration of A at the anode, (A)_a, to that atthe cathode, (A)_c, i. e., Y_A = (A)_a/(A)_c; similarly, Y_B=(B)_c/(B)_a; Y_c= (C)_a/(C)_c; Y_D =(D)_c/(D)_a. Y=Y_AY_B=Y_CY_D=exp{(1-g)nFE/RT}, where n, R, T have theusual meaning as used in electrochemistry. At any given stage of titration, x and Y are known, then Y_j's (j=A, B,C, D) may be calculated as follows: Y_j=Q(Y-1)+(Q~2(Y-1)~2+Y)~(1/2) (3)In the above expression, when j=A, Q=x-0.5; when j=B, Q=0.5-x;when j=C, Q=0.5-1/x; when j=D, Q=1/x-0.5. Since g is a measurable quantity, Y is a function of g and E, so thatequation (1b) provides a convenient means to evaluate S and hence k_A. Differentiating (1c) with respect to x, we obtain (dg/dx)_(x→1)=-SE~(-1)(Y-1)/(Y+1) (4)this is the expression for the steepness of the current change near the endpoint. The theoretical titration curves and their slopes near the end point as cal-culated with the aid of the equations (1), (3) and (4) were plotted in Fig. 2 (p. 8),where the applied voltage being fixed at 59 mv but the dead-stop titrationconstant S has been varied tenthousand-fold. From this figure we may drawthe following conclusions: (1) At the given applied voltage, the larger the S the steeper the titra-tion curve. Steeper curve will give more sharp end point, but it is not ad-vantageous if the curve is too steep, since there will be no warning whenapproaching the end point and a drop of the reagent may be sufficient to causea jump from the left to the right branch of the titration curve over thecurrent minimum. The most suitable value of S is in the order of magnitudeof ten. (2) For the titration of Ce (IV) with Fe (II) at room temperature usingtwo platinum foil electrodes of area of about 0.8 square centimeters, we foundk_A is in the order of magnitude of 0.1. Since S=k_AC_0R the product of C_0and R should be in the order of magnitude of 10~2. If C_0=10~(-3)M then a resistanceof about 10~5 ohms should be inserted. (3) Since k_A=nFAD_A/δ, the factors which determine k_A are: the elec-trode area A, the diffusion coeficient D_A and the effective thickness of the diffusion layer δ, these latter quantities are effected by the temperature andthe viscosity of the solution, the rate of stirring, etc. Fig. 3 is a similar plot, but in this case S is fixed at 0.59, while E variesfrom 5.9 to 590 mv. From this figure we see that the slopes of the titrationcurves for E=295 and 590 mv are smaller than those for E=118, 59 and 5.9mv, so that an applied voltage over several hundreds mv is usually disadvan-tageous in the dead-stop titration. On the other hand, too small an appliedvoltage is also inconvenient because then a much more sensitive galvanometermust be used and the current readings will sometimes be erratic due to sometemporary polarization effects. The experimental test of the above theory will be reported in the nextcommunication.

An experimental verification of the theoretical peak current equation forreversible electrode reactions of the Randles-Sevcik oscillopolarography, i_p=Kn~(3/2)D~(1/2)m~(2/3)θ~(2/3)α~(1/2)cμΑ, is carried out with both single- and multisweep methods. Themultisweep method is essentially that of Delahay, while a simplified circuit isdevised for the single-sweep procedure. The constant K in the above equation has been worked out by Randlesand Sevcikc, but their values differ by some twenty-one percent. Experimentalresults...

An experimental verification of the theoretical peak current equation forreversible electrode reactions of the Randles-Sevcik oscillopolarography, i_p=Kn~(3/2)D~(1/2)m~(2/3)θ~(2/3)α~(1/2)cμΑ, is carried out with both single- and multisweep methods. Themultisweep method is essentially that of Delahay, while a simplified circuit isdevised for the single-sweep procedure. The constant K in the above equation has been worked out by Randlesand Sevcikc, but their values differ by some twenty-one percent. Experimentalresults as to which K value is correct have been contradictory. The authorspoint out that Sevcik's value of K is too low, due to the error in choosing too largea unit in his numerical integration. By taking smaller units and reperformingthe integration, the K value increases and approaches that of Randles. Thus thecorrectness of Randles' K value is ascertained and this value is used in calculatingthe theoretical slope. Their single-sweep results, with concentrations from 2×10~(-4) to 1×10~(-3) m/l andα~(1/2) from 1 to 4 volts/sec, agreement between experimental and theoretical slopesis obtained in the case of Tl~+ in m NaCl. In the case of Cd~(++) in m NaCl, experi-mental results deviate from the theoretical value, and the deviation increases withincreasing c and α~(1/2). Contrary to an unproven idea of Delahay, i_p obtained bymultisweep method is higher than that by the single-sweep procedure. However,in calculation of the theoretical values, a value of 15.0×16~(-6) obtained by polarLographic method is used for D of Tl~(+) in m NaCl. The use of the value of Dat infinite dilution is thought to be unjustified. If a D value of 15.0×10~(-6) is used,Delahay's results of Tl~+ in KNO_3 would be higher than the theoretical equationinstead of agreeing with it. This fact seems to support the findings of this paper. Various methods of correcting for capacity currents are compared and discus-sed. The authors point out that at α~(1/2) less than 2 volts/sec, the method of drawingan hbrizontal line introduces no appreciable error while at, high α, various methodsyield different results. This fact lowers the accurraey of data obtained at high α. The iR drop in the electrolytic cell and on the series resistance causes themeasured α to be different from the a actually applied on the drop electrode. Anelementary approximate correction of this effect is mentioned. Results after thiscorrection show that the deviation of Cd~(++) from theoretical at high c and α maybe due partly to this effect.