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Friday, March 10, 2017

Process Simplification and The Art of Exploiting Physical Properties

Chemical additives, petrochemicals, plastics and pharmaceuticals are different reacted forms and formulations of organic (fine/specialty) and inorganic chemicals. We have mastered their use and continue to develop new uses to make our lives easier.

We are also familiar with or can find chemical and physical properties of the chemicals that are used in these applications. However, many of us have not totally understood or mastered their mutual behavior and/or how their mutual behavior can be used/manipulated/modified/exploited to simplify processes, especially the reactive processes. To some extent it is an art that can significantly improve profitability.  

Simpler processes streamline manufacturing. They are sustainable and assist in many other ways e.g. lower costs, higher profit, improve supply chain, give competitive edge through better product quality.

We have to ask ourselves a question “are we exploiting physical and chemical properties to their fullest extent?” If we are not, then the question is why not? Answer is very simple, at least to me. Values and virtues of physical and chemical are taught. However, we generally are not taught how to exploit them. I learnt from my mentors and colleagues. Shortcomings have been discussed in the past (1,2,3,4) and in many other publications. If we can understand and manipulate their mutual social behavior “sociochemicology” we should be able to create, design and simplify many of the reactive or formulation processes.

Collectively fault lies with us. Why? When developing a new process we don’t have the time to exploit these properties.
Opportunities are tremendous, however, getting from studying to practicing may not be the simplest. We do practice what we are taught, but not to the extent we could. Traditions also come in the way of exploitation. Most of the time textbook methods and laboratory practices are followed.

Everything has to be done yesterday and the pressure to have the process ready to be scaled up day before yesterday is omnipresent. With such constraints even the best, creative and imaginative chemists and chemical engineers can falter. Processes are commercialized and they may not be the most optimum. Generally such processes are accepted in the chemical industry. Continuous improvement opportunities allow us to better these processes. However, there are applications where commercializing a perfect process that has very stringent tolerances and meet certain regulatory needs are a must. Electronic chemicals and pharmaceuticals fit the higher tolerance regimen with pharmaceuticals due to regulations being even more demanding. Second chances in these areas can cost significant time and money.

Process Development Opportunities:

Process development is done in the laboratory and at times circumstances are not helpful to think BIG. By BIG, I mean how we will deal with commercial quantities of raw materials and intermediates. Our “Imagineering” falters somewhere when we are scaling up from the lab to a commercial process. We pay a price via higher product cost and at times with lack of first time product quality because we have not spent the time needed to create an efficient economic process.

Exploitation and imagineering of physical and chemical properties of the chemicals to create an economic process can be an art which depends on “eye of the designer”. Individual imprints come from our experiences and understanding of unit processes and unit operations.

I have used one of the physical properties as an example to illustrate how we can master/exploit sociochemicalogy to create and commercialize excellent and sustainable processes.

Liquids are Developer’s Best Friend: 

Every chemical comes in its natural state in one of the three forms: gas, solid and liquid.

At room temperature gas cannot be held in hand where as solid and liquid can be handled. When it comes to handling gases in the lab they are a challenge. Liquefied gas handling has use constraints in the lab. They can be a challenge in plants also. Special equipment would be needed if liquefied gas were to be handled. Since many labs are not equipped, gases are dissolved in a liquid and used in process development. Use of ammonia as ammonium hydroxide is an example. Process productivity can be lost when dilute gas solutions are used. Commercial handling of liquefied gases requires special attention and is product volume dependent.

In laboratory, solids are generally dissolved in appropriate solvent and used as a dissolved solution. Depending on solubility at room temperature process productivity can be significantly impacted. On commercial scale if the solid raw material can be used as a melt, it would be ideal, as the process will have high productivity. Again process economics and product demand come into play.

Raw materials, reaction intermediates and products as liquid are easiest to handle. Our ability to recognize the differences in density, mutual solubility, boiling point differences and other physical properties and exploit them to our advantage generally results in an economic and sustainable process (4,5,6). Exploitation of physical and chemical properties is not a cookie cutter exercise but is more like a precision surgery for each process, especially for the reactive processes.

There are many chemical reactions that can be commercially done in all liquid phase when the raw materials are solid or gas at room temperature. With sufficient residence time and using fundamental of chemistry and chemical engineering the produced product can be purified to produce global needs from a single plant. Latent advantages of such processes are very high productivity with minimal use of diluting solvents that are necessary in conventional processes. One has to imagine, explore and look. As explained earlier reason and rational for not looking in the lab is that we do not have the necessary equipment to explore such reactions. Many times such opportunities are never explored even after commercial success of such products.

Many books can be written about how sociochemicology of the chemicals can be used and improved to commercial advantage. It is best that such methods be left to the imagination of chemists and chemical engineers. Given a chance they are extremely creative, imaginative and resourceful and the results would magnificent.

Girish Malhotra, PE
EPCOT International

  1. Malhotra, Girish: A Radical Approach to Fine/Specialty API Manufacturing, Profitability Through Simplicity January 20, 2010
  2. Malhotra, Girish: Focus on Physical Properties To Improve Processes: Chemical Engineering, Vol. 119 No. 4 April 2012, pgs 63-66
  3.  Malhotra, Girish: Industry 4.0 (Digitization): Its Benefits to Pharma and Other Chemical Industries, Profitability through Simplicity, November 11, 2016
  4.  Malhotra, Girish: Chemical Process Simplification: Improving Productivity and Sustainability, ISBN: 978-0-470-48754-9, January 2011, John Wiley & Sons Inc.
  5.  US patents: 3,928,457; 4,945,184; 5,004,839; 3,564,001; 4,363,914
  6. McCabe, W. L. and Smith, J.C. Unit Operations of Chemical Engineering, McGraw-Hill, Inc. 1956; 40

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