Molecular distillation

Molecular distillation is vacuum distillation below the pressure of 0.01 torr.[1] It is a process of separation, purification and concentration of natural products, complex and thermally sensitive molecules for example vitamins and polyunsaturated fatty acids. This process is characterized by short term exposure of the distillate liquid to high temperatures, by high vacuum pressure (around 1024 mmHg) in the distillation column and a small distance between the evaporator and the condenser around 2 cm,[2] where fluids are in the free molecular flow regime, i.e. the mean free path of molecules is comparable to the size of the equipment.[3] This process has advantage as it avoids problems of toxicity that occurs in techniques that uses solvents as the separating agent, also it can minimize losses due to thermal decomposition.

Molecular distillation is used industrially for purification of oils.[4][5]It is also used to enrich borage oil in γ-linolenic acid (GLA) and also to recover tocopherols from deodorizer distillate of soybean oil (DDSO).[2]

See also

References

  1. ↑ Vogel's 5th ed.
  2. 1 2 http://www.nt.ntnu.no/users/skoge/prost/proceedings/distillation06/CD-proceedings/paper062.pdf
  3. ↑ Lutišan, Juraj; Cvengroš, Ján (1995-01-01). "Mean free path of molecules on molecular distillation". The Chemical Engineering Journal and the Biochemical Engineering Journal 56 (2): 39–50. doi:10.1016/0923-0467(94)02857-7.
  4. ↑ Wang, Shurong; Gu, Yueling; Liu, Qian; Yao, Yan; Guo, Zuogang; Luo, Zhongyang; Cen, Kefa (2009-05-01). "Separation of bio-oil by molecular distillation". Fuel Processing Technology 90 (5): 738–745. doi:10.1016/j.fuproc.2009.02.005.
  5. ↑ Martins, P. F.; Ito, V. M.; Batistella, C. B.; Maciel, M. R. W. (2006-02-01). "Free fatty acid separation from vegetable oil deodorizer distillate using molecular distillation process". Separation and Purification Technology 48 (1): 78–84. doi:10.1016/j.seppur.2005.07.028.
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