C rate

Davies and Warren have investigated the nitration of naphthalene, ace-naphthene and eight dimethylnaphthalenes in acetic anhydride at o °C. Rates relative to naphthalene were determined by the competition method, and the nitro-isomers formed were separated by chromatographic and identified by spectrophotometric means. The results, which are summarised in the table, were discussed in terms of various steric effects, and the applicability of the additivity rule was examined. For the latter purpose use was made of the data of Alcorn and Wells (table 10.2) relating to the nitration of monomethyl-naphthalenes at 25 °C. The additivity rule was found to have only limited utility, and it was suggested that the discrepancies might be due in part to the... 

Fig. 2. Typical stress—strain properties of staple fibers at 65% rh and 21°C. Rate of elongation is 50%/min. To convert N/tex to gf/den, multiply by 11.3.

R. B. Blodgett, "Ethylene—Propylene Rubber and Crosslinked Polyethylene as Insulations for 90°C Rated Medium Voltage Cables," Rubber Chem. Technol, 52, 410-424 (1978). 

AppHcatioas of dibasic lead phthalate, coated grade, iaclude 90 and 105°C rated PVC electrical iasulation, plastisols, profile extmsions, calendered sheet, and molded products. The recommended range of usage ia viayl electrical iasulatioa is 5—7 parts pet huadred resia, depending oa the particular iasulatioa classiftcatioa to be met. Ia geaeral-purpose extmded and molded PVC stocks, approximately 3—6 phr of coated dibasic lead phthalate is suggested. 

Moulded case circuit breakers and moulded case switches up to 1000 V a.c. Rating more than 5000 A Moulded ease circuit breakers and their application, up to 1000 V a.c. Rating 5000 A and more Low-voliage cartridge fuses... 

If there is a rise of 5% in the effective resistance of the busbars due to the skin effect, then the a.c. rating will be... 

A.C. ratings are based on spacings, at which the proximity effect is considered almost negligible ( > 300 mm. Section 28.8). 

C) rate-controlling o-complex formation (selective electrophile)... 

C, = rate of loss or gain by chemical reactions, precipitation (washout), or adsorption by suspended particles... 

Once in an operational battery, the separator should be physically and chemically stable to the electrochemical environment inside the cell. The separator should prevent migration of particles between electrodes, so the effective pore size should be less than 1pm. Typically, a Li-ion battery might be used at a C rate, which corresponds to 1-3 mAcm2, depending on electrode area the electrical resistivity of the separator should not limit battery performance under any conditions. 

Table 5-2. Selected rate constants and half-livese) for some reactions of substituted benzenediazonium ions with buffer solutions (pH 9.00) at 25 °C (rate constants from Virtanen and Kuok-kanen, 1977 half-lives calculated by the present author).

A kinetic study of the electrophilic substitution of pyridine-N-oxides has also been carried out50b,c. Rate-acidity dependencies were unfortunately given in graphical form only and the rate parameters (determined mostly over a 30 °C range) are given in Table 4b. There is considerable confusion in Tables 3 and 5 of the original paper, where the rate coefficients are labelled as referring to the free base. In fact the rate coefficients for the first three substituted compounds in... 

Under flow conditions. b Also given as 2.55 in the same paper. c Rates relative to naphthalene. 

Kilpatrick and Meyer163 measured the first-order rates of sulphonation of some alkylbenzenes by sulphuric acid at 12.3 °C. Rate coefficients were given graphically only and the parameters for the linear log (k x 106) versus —a+b [H2S04] plots (where the stoichiometric acid concentration is expressed in mole.l-1) were as follows, the acid range examined being given in parentheses ... 

Rate coefficients for reaction with 4,4-dichlorodiphenylmethanol. b Rate coefficients for reaction with diphenylmethyl acetate. c Rate coefficients for reaction with [4-3H]-anisole as aromatic. 

An exceptionally badly reported kinetic study in which a linear correlation of rate coefficient with acidity function was claimed was that of Mackor et al. 11, who studied the dedeuteration of benzene and some alkylbenzenes in sulphuric acid-trifluoroacetic acid at 25 °C. Rates were given only in the form of a log rate coefficient versus —H0 plot and rate coefficients and entropies of activation (measured relative to p-xylene) together with heats of activation (determined over a temperature range which was not quoted) were also given (Table 129). However,... 

Nesmeyanov et a/.545 used a mixture of ferrocene, deuterated trifluoroacetic acid and benzene in the molar ratios 1 2 20 in a preliminary investigation of the reactivity of ferrocene and its derivatives. At 25 °C, rate coefficients were 1,620 x 10-7 (ferrocene) and 19.3 xlO-7 (acetylferrocene). In a subsequent publication by Alikhanov and Shatenshtein543 these values were altered to 1,600 x 10-7 and 1.5 x 10 7, respectively, and a value of 0.77 x 10"7 added for 1,1-diacetylferrocene. Under the same conditions, toluene gave a value of 0.3 x 10-7 so that the activating effects of these compounds relative to benzene can be approximately determined. 

Nesmeyanov et a/.546 have also measured the effects of substituents in deuteration of ferrocene by deuterated trifluoroacetic acid in dichloromethane at 25 °C. Rate coefficients were measured for ferrocene and its derivative in a range of such acid mixtures, the composition of which was omitted, and in some cases the rate of exchange for ferrocene was calculated on the basis of a linear relationship between log and —H0. Results including the calculated knl values are given in Table 161. It should be noted that, in discussing those results, the authors quoted the incorrect partial rate factors for dedeuteration of toluene arising from the use of the incorrect data for benzene (see p. 199). This should be taken into account... 

The effects of substituents have been determined in the cleavage of diaryl-mercury compounds by hydrogen chloride in dimethyl sulphoxide-dioxan at 32 °C. Rates were measured within the temperature range 12.8-75.0 °C, though over a range of not more than 18 °C for each compound611 (Table 184). The... 

Extension of these studies to formic acid media (containing 4 vol. % ethylene glycol and 1.3 vol. % water) showed that for protodeboronation of 4-methoxy-benzeneboronic acid at 25 °C) rates were invariant of a tenfold variation in acidity produced by adding sodium formate (0.05-0.20 M) to the medium (Table 194), and in this range the concentration of molecular formic acid is essentially constant. This was, therefore, assumed to be the reactive species. At higher acidities the rate increased, which was attributed to the increase in concentration of hydronium ions and protonated formic acid ions which bring about reaction more readily625. 

GC assay of the organic layer showed no EIN(TMS)2 remaining after 15 min of stirring (GC conditions Restek RTX-1 column (30 m x 0.53 mm, 1 m film thickness), 2.53 mL/min, initial temperature 50°C, final temperature 300°C, rate 20 deg/min, injection temperature 200°C, detector temperature 350°C, injection volume 1 pL, inject sample neat retention times fert-butyl alcohol 1.4 min, THF 1.7 min, heptane 2.1 min, HN(TMS)2 2.6 min, ethylbenzene (present in commercial LHS) 3.1 min, te/ t-butyl acetate 4.0 min). Volume percents were determined based on standard solution counts. 

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