TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The composition comprises an aqueous phase and an ionic liquid phase. Preferred Components: The salt further comprises a cation chosen from group IA metal, group IIA metal, transition metal, and ammonium. The cation is chosen from lithium, sodium, potassium, magnesium, calcium, and ammonium. The salt is potassium phosphate or potassium hydrogenphosphate. The ionic liquid comprises an ionic liquid cation, where the ionic liquid cation is chosen from optionally substituted imidazolium, optionally substituted pyridinium, optionally substituted pyridazinium, optionally substituted pyrimidinium, optionally substituted pyrazinium, optionally substituted pyrazolium, optionally substituted thiazolium, optionally substituted 1,2,3-triazolium, optionally substituted 1,2,4-triazolium, optionally substituted oxazolium, optionally substituted isoquinolinium, optionally substituted quinolinium, optionally substituted pyrrolidinium, optionally substituted piperidinium, and their mixtures. The ionic liquid cation is optionally substituted imidazolium or optionally substituted pyridinium. The ionic liquid comprises an ionic liquid anion, where the ionic liquid anion is chosen from halide, lactate, acetate, perchlorate, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, nitrite, nitrate, sulfate, phosphate, hydrogenphosphate, triflate, carbonate, 2-6C carboxylate, and their mixtures. The ionic liquid anion is chosen from halide, lactate, and acetate. The ionic liquid anion is acetate. The ionic liquid is a 1,3-dialkylated imidazolium salt of formula (I).R1,R3=optionally substituted 1-6C alkyl, or unsubstituted 1-6C alkyl.. The ionic liquid is 1-ethyl-3-methylimidazolium acetate or 1-butyl-3-methylimidazolium acetate and the salt is potassium phosphate or dipotassium phosphate. The ionic liquid is 1-ethyl-3-methylimidazolium acetate and the salt is potassium phosphate. The aqueous phase comprises 0-2 wt.% of the ionic liquid. The aqueous phase comprises 0-1 wt.% of the ionic liquid. The aqueous phase comprises 0-0.5 wt.% of the ionic liquid. The aqueous phase comprises 20-60 wt% of the salt. The aqueous phase comprises 30-50 wt.% of the salt. The aqueous phase comprises 35-45 wt.% of the salt. The biomass comprises lignin and cellulose, where the precipitated solids comprise cellulosic material containing at least 50% of the lignin originally present has been removed. Preferred Method: The method further involves recycling the ionic liquid phase in a subsequent pretreatment. The heating the product at 100-180 degrees C, preferably 120-160 degrees C. The heating is carried out at a temperature of 130-150 degrees C. The method further involves providing conditions for enzymatic hydrolysis of the precipitated solids. The enzymatic hydrolysis is carried out with cellulase enzymes. The method further involves cooling the pretreated biomass composition prior to the contacting step. The method involves ionic liquid (85-100%) is recovered after separation from the precipitated solids and the aqueous phase. The method involves ionic liquid (90-100%) is recovered after separation from the precipitated solids and the aqueous phase. The method involves ionic liquid (95-100%) is recovered after separation from the precipitated solids and the aqueous phase. Preferred Definitions:    R1,R3=methyl, ethyl, propyl, isopropyl, butyl, isobutyl or tert-butyl.    EXAMPLE - No suitable example given.