Distillation loss

Distillation loss the difference, in a laboratory distillation, between the volume of liquid originally introduced into the distilling flask and the sum of the residue and the condensate recovered. 

Table II and Figure 1 data show di-2-ethylhexyl azelate (DEHZ) has excellent low viscosity at low temperature along with good volatility properties. Figure 1 shows the DEHZ to have substantially lower volatility than DIOA and actually lower volatility than 4 cSt polyalphaolefin (PAO-4) in the initial distilled loss area of the curves. The slopes of the PAO and petroleum curves in Figure 1 indicate they are composed of a distribution of different molecular weight species, whereas the relatively flat curves of the esters indicate they are essentially composed of a single chemical species. As a result, there are little or no low molecular weight ends to increase the volatility of these diesters. Even though the PAO is a very narrow distillation cut, it is still composed of a blend of dimers, trimers, tetramers, and pentamers, and does exhibit volatility caused by the low ends as demonstrated in Figure 1.

Improvement of the deodorizer design by the installation of baffles and demisters in the vapor chimneys has significantly reduced entrainment losses to 0.1-0.2% in chemical refining. For steam refining, an additional loss directly proportional to the FFA content has to be taken into account. For most oils (soybean oil, pahn oil, etc.), NOL is exclusively due to mechanical carry-over. However, in lauric oils, part of the NOL is a consequence of effective evaporation of volatile short-chain mono- and diacylglycerols (30). (Table 13). This distillation loss of NOL is inherently due to the deodorization conditions, but is not affected by the deodorizer design. 

An alternative and more convenient separation is to distill about 20% of the reaction mixture into a septum tube and separate10 by g.l.c. using a silicone active phase. This procedure avoids distillation losses, allows ready separation from methyl iodide, and allows the recovery of polymethyldigermanes. 

Other test procedures for the direct determination of catalyst activity have been proposed by Birkhimer, Macuga, and Leum (22), Shankland and Schmitkons (23), and Conn and Connolly (24). These are essentially similar to the CAT A method, except for the details of operating conditions and reporting of test data. In addition to the carbon and gas yields, the per cent recycle stock ( unconverted charge stock boiling above 400°F.), the conversion (100% — % recycle stock), and a quantity called D + L (per cent distillate to 400°F. plus distillation loss) are factors reported from the test data. The overall activity of the... 

See compilations by Busemann et al. (2000) for extraterrestrial data and Graham (2002, this volume) for mantle data. MFL is the fractionation line for mass-dependent Rayleigh distillation losses. 

A further opportunity for process optimisation involves the judicious selection of reaction conditions (temperature, pressure and hydrogen / hydrocarbon ratio) so as to promote the transfer of primary middle-distillate product into the vapour phase with a view to reducing its residence time in the catalyst bed and, consequently, preventing distillate loss via secondary cracking. This approach to improved overall distillate selectivity has previously been referred to by Filers et al. [2] and provides the incentive to optimise catalyst performance within the constraints of the operating window so defined. 

Arithmetical Procedure—Deduct the observed distillation loss from each prescribed percentage evaporated in order to obtain the corresponding percentage recovered. C culate each required thermometer reading as follows ... 

Report observed temperatures to the nearest 0.1 C, in a manner conforming to the specifications of the material tested. If no definite manner of reporting is specified, report the corrected temperatures at each observed volume, and report the volume percentages of residue, recovery, and distillation loss. 

If any residue is present, cool to room temperature and pour into a small cylinder graduated in 0.1-mL subdivisions. Measure the volume and record it as residue. Record the difference between 100 and the sum of the residue plus recovery as distillation loss. 

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