Distillation interconversion

Source Daubert, T. E., Petroleum Fraction Distillation Interconversions, Hydrocarbon Processing, September 1994, pp. 75-78. 

Nonetheless, if contact with acidic and basic substances is rigidly excluded to the extent of using quartz equipment in place of glass (glass normally has a slightly alkaline surface), then interconversion is slow enough that it is possible to separate the lower-boiling enol from the keto form by fractional distillation under reduced pressure. The separated isomers are indefinitely stable when stored at —80° in quartz vessels. 

Figure 5. The Amoco Easy-Hard kinetic model for resid hydrotreating. The reaction products are characterized by seven distinct lumps, the three feedstock species which are shaded in gray (resid hard, resid easy, and gas oil) and the four new components which are not shaded (gas, naphtha, distillate, and gas oil). The kinetic interconversion of these groups is described by the 14 constants (3).

Interconversion of a thioxocarboxylic ester with an alcohol can be achieved in the presence of a base. The reaction takes place with high yields if amino alcohols or diols are used. A series of macro-cyclic polyether thioxoesters has been prepared by treating (9,(9 -diethyl dithiooxalate and 0,0 -dimethyl 2,6-pyridinedicarbothioate with glycols. Methanol or ethanol were removed from the equilibrium mixture by distillation or adsorption in molecular sieves (equation 48). ... 

Dry distillation of benzodiazepinium salts may also lead to formation of a ketone and a benzimidazolium salt.23 A number of benzodiazepinium salts contain water of crystallization and this, or adsorbed water, must presumably participate in the reaction. It is possible that some of the quoted melting points of benzodiazepinium salts are in fact those of the benzimidazolium salts, interconversion having taken place at a lower temperature. 

Organopseudohalosilanes are easily soluble in organic solvents. Water converts them into silanols or siloxanes. The azidoorganosilanes are especially susceptible to hydrolysis. Moisture must be strictly excluded from all preparations and interconversions of these azido compounds. Otherwise, hydrazoic acid is formed. When concentrated in distillation residues, it causes explosions and if inhaled, headaches. 

We develop a spreadsheet which allows interconversion between different ASTM distillation types based on the correlations from [2] (see Figure 1.1) ... 

Figure 6.19 Interconversion between different ASTM distillation types.

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