Introduction: Although soap industry is known from hundreds of years, the development
accompanied with this industry was little. The development implied the mechanical
equipment and the additive materials necessary to produce soap with the best specifications
of shape, physical and chemical properties.
Objectives: This research studies the use of vacuum reactive distillation VRD technique for
Methods: Olein and Palmitin in the ratio of 3 to 1 were mixed in a flask with NaOH solution
in stoichiometric amount under different vacuum pressures from -0.35 to -0.5 bar. Total conversion
was reached by using the VRD technique. The soap produced by the VRD method
was compared with soap prepared by the reaction - only method which is known as the conventional
method. The two kinds of soap were compared in yield, the reaction temperature,
the volume of the co-product liquid and its composition, FTIR analysis, the density and the
time of production.
Results: It was shown that the yield of soap using VRD was 2.45 times that produced by the
reaction - only method. The process temperature was reduced 0.11 times. The volume of the
co-product liquid was reduced 95.76% consisting of water only. The analyses of FTIR were
compared with a commercial soap regarded as a standard and they showed identical functional
groups. Very little difference in density was recorded. The time of production was
shorter than the conventional method giving another priority to the VRD method.
Conclusion: It was beneficial to adopt VRD method in soap production in batch mode. Continuous
mode of soap production using VRD method may be investigated in future study.