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Separation of isopropanol from aqueoussolution by salting-out extractionTang Zhigang,Zhou Rongqi and Duan ZhantingChemical Engineering Department, Tsinghua University, Beijing 100084, Peoples Republic of China

NOTATION

INTRODUCTION

(Received 1 August 2000; revised version received 14 March 2001; accepted 19 March 2001

Correspondence to: Tang Zhigang, Chemical Engineering Department, Tsinghua University, Beijing 100084, Peoples Republic of China

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EXPERIMENTALMaterials and reagents

Screening of extracting agent

Screening of salting-out agent

Figure 2. Isopropanol and water separation by salting-out extraction

coupled with azeotropic distillation.

Figure 1. Isopropanol and water separation by azeotropic distillation.

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Analytical methods

RESULTS AND DISCUSSIONScreening of salting-out agent

Table 1.Salting-out effects of different inorganic salts a (20C)

Figure 4.Comparison of salting-out strength with integral heat ofdissolution for salt (Dal/D0data were adapted from Table 1; dissolution heat

data collected from Ref 14) symbol represents heat-absorbing and

represents heat-releasing.

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Factors effecting LLE

Figure 6.Distribution coefficients of isopropanol and separation

coefficients of isopropanol vs water at different salt concentrations (28 C).

(a) equilibrium aqueous potassium carbonate concentration was94.50g dm3; (b) equilibrium aqueous potassium carbonate concentration

was 190.1g dm3; (c) equilibrium aqueous potassium carbonate

concentration was 278.2g dm3.

Figure 5. LLE of hexane/isopropanol/aqueous solution with differentpotassium carbonate concentrations at 28C. (Note: The extrapolated

curves are trend curves plotted using Microsoft Excel of the experimental

data at the same conditions.)

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Salting-out extraction experiments

Figure 7. LLE of hexane/isopropanol/10% potassium carbonate aqueoussolution at various temperatures. (Note: The extrapolated curves are trend

curves plotted using Microsoft Excel of the experimental data at the same

conditions.)

Figure 8.LLE of hexane/isopropanol/10% potassium carbonate aqueoussolution at various pH values. (Note: The extrapolated curves are trend

curves plotted using Microsoft Excel of the experimental data at the same

conditions.)

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CONCLUSIONS

REFERENCES

Table 2.Salting-out extraction results