1,1,1-trichloroethane, density

Figure 6. Weight change of medium density polyethylene as a function of time following immersion in 1,1,1-trichloroethane...

Many workers have in fact used density matrix methods for the calculation of line shapes and intensities in multiple resonance experiments, and two excellent reviews of the background theory are available. (49, 50) In addition there is also a simple guide (51) to the actual use of the method which is capable of predicting the results of quite elaborate experiments. Major applications have included the calculation of the complete double resonance spectrum from an AX spin system which gives 12 transitions in all (52) an extremely detailed study of the relaxation behaviour of the AX2 systems provided by 1,1,2-trichloroethane and 2,2-dichloroethanol (53) the effects of gating and of selective and non-selective pulses on AB and AX spin systems and the importance of the time evolution of the off-diagonal elements of the density matrix in repetitively pulsed FT NMR and spin-echo work (54) the use of double resonance to sort out relaxation mechanisms and transient responses (55) the calculation of general multiple resonance spectra (56) and triple resonance studies of relaxation in AB and AX spin systems. (57)... 

The /nfpr-molecular NOE is mentioned above briefly. It is of course this which makes it desirable to use samples in a solvent without nuclei of high for these experiments. There have, however, been few detailed studies of this effect. (234) A density matrix description (235) has been successfully applied to the effect upon the solute (1,1,2-trichloroethane) protons of irradiating the solvent (Me4Si) resonance (235) and differential effects upon the resonances of the [AB]2 spin system provided by the protons of o-dichlorobenzene have been used to aid the assignment. (236)... 

Place 10 mL of 1,1,1-trichloroethane in a 50-mL volumetric flask and, by means of a pipet, introduce a test specimen as indicated in Table 1. Either obtain the weight of specimen introduced by difference between the weight (to the nearest 1 mg) of the flask before and after addition of qiedmen or, if the density is known accurately, calculate the weight firom the measured volume. HU the flai to the marie with 1,1,1-trichloroethane and mix weU. (Warning—See Note 11.)... 

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