TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: Separation of (A) is carried out using the extractant in cocurrent or counter-current, or by bubbling (A) through the extractant. The extractant is regenerated by pressure reduction, exposure to reduced pressure or vacuum and/or temperature increase. At least two loading and regenerating devices are preferably used, loading and regeneration each being carried out in at least one of the devices. Two or more liquid-gas extractions are optionally carried out in series, using extractants of different compositions. (A) is dried before the liquid-gas extraction, specifically by cooling and/or condensing out water, drying using a condensate separator, use of a molecular sieve and/or by swing absorption in an alumina bed. Carbon dioxide is separated from the other components of (A) by the gas-liquid extraction, specifically before a multistage compression process (or one of the compression stages) or after the multistage compression process. The carbon dioxide-free (A) is used in water-gas shift reaction processes. Carbon monoxide is separated from (A), specifically for use as a starting material in a shift reaction for hydrogen recovery and/or in the steam dealkylation apparatus. Methane and other lower alkanes are separated from (A), specifically for use as fuel in the plant, especially for generating heat necessary for the steam dealkylation reaction. Hydrogen is separated from compressed (A) by pressure swing absorption, specifically for use as a starting material in the steam dealkylation apparatus or another hydrogen-utilizing process in the plant, and/or as a valuable product from the plant.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Ionic Liquids: (I) are of formula aAm+.bBn- (I').a, b = integers;m, n = 1 or 2;a.m = b.n;A = quaternary ammonium, quaternary phosphonium, imidazolium, pyridinium, pyrrolidinium, pyrazolium, 1,3,5-triazolium, pyrimidinium, quinolinium, isoquinolinium, morpholium, oxazolium, isoxazolium, thiazolium, guanidinium, isouronium or isothiouronium cation (all containing a very wide range of specific organic groups and optional substituents);B = anion, preferably selected from PF6-, BF4-, CF3COO-, CF3SO3-, (CF3SO2)2N-, (CF3SO2)(CF3COO)N-, R4SO3-, R4OSO3-, R4COO-, Cl-, Br-, I-, NO3-, N(CN)2-, HSO4-, R4R5PO4-, CN-, SCN-, ClO3- or ClO4-;R4, R5 = H, 1-20C saturated or unsaturated aliphatic or alicyclic group or -Q-Ar;Q = direct bond or 1-6C alkylene;Ar = 3-8C heteroaryl (containing at least one N, O and/or S heteroatom) or 5-12C aryl (both optionally substituted by one or more 1-6C alkyl and/or halo). EXAMPLE - No relevant example given.