WeylChem Avoids Process Safety and Thermal Hazard Analysis Risks by Studying Heat Generation at the Click of one Button

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Creating runaway scenario conditions for scaling-up a process from lab to production is challenging. It becomes increasingly difficult when a self detonating molecule is involved. WeylChem Corporation overcame this challenge by using the right tools: a METTLER TOLEDO RC1e reaction calorimeter in combination with the iC Safety™ software module. That's how they avoided any process risks.

Process Safety at WeylChem

WeylChem Corporation, a global fine chemical company specializing in custom synthesis, performed a series of reactions to develop a synthesis of 2,4-diformylmesitylene (DFM) that would be scalable to production. A synthetic protocol1 was previously published, however it was felt improvements could reduce material costs and improve reaction safety. The synthesis involves the use of potassium 2-nitropropane as a key reactant. This molecule has been known to self detonate upon standing,2 which required WeylChem to produce and use the salt in situ. Understanding the energy involved with accumulation and reaction of this salt was necessary to ensure plant conditions would not permit a runaway reaction.

To learn more, view the free on-demand webinar Safe Process Scale-up - A Case Study of Nitroalkane Chemistry by WeylChem presented by Kevin Drost of WeylChem.

Experiments were carried out in a METTLER TOLEDO RC1e™ reaction calorimeter, automated with iControl™ software. An initial set of three experiments was run using different addition rates to assess the impact of feed rate on the heat of reaction, thermal accumulation and maximum temperature rise with cooling failure. iC Safety™ was used to consolidate data from the RC1e™ with data from GC and DSC analysis. iC Safety™ is a software package designed to speed up data analysis and preparation of thermal hazard analysis.

iControl RC1e™ and iC Safety™ were used by WeylChem to simplify and speed up thermal hazard analysis; charts are easily generated from the experiments to show (a) KOH solution addition, (b) heat of reaction, (c) thermal conversion and (d) thermal accumulation.

From only three experiments, WeylChem was able to get useful data from iC Safety™. This data provided good insight into the heat of the reaction as well as the amount of heat generated during different portions of the reaction. Without iC Safety™ and an RC1e™ they would not have discovered how exothermic this reaction was until the reaction was scaled-up. (Lab runs did not show any heat kick or large exotherm). They found that the amount of heat generated precluded them from doing the fast feed they had envisioned. With three different feed rates and subsequent heat ups, they were able to obtain enough data to allow them to extrapolate cycle times, run-away scenarios and cooling failure issues. From this study, in conjunction with additional DSC data, WeylChem feel confident they have developed a protocol that will allow for reaction scale-up to a plant production scale in the future. In addition, this added informaton allowed for a more accurate costing on this desired intermediate molecule.

Another aspect of iC Safety™ is the speed in which data is obtained (i.e conversion of raw data into usable data.) Previously, the turnaround time from running a reaction to issuing data was days if not longer. With the new software and little manipulation, data is available immediately. This allows for more time to digest the information, get additional data, make changes and run additional experiments and still obtain more useful data in shorter periods of time. Some of the data obtained from iC Safety™ was almost impossible to obtain previously (TCF curves, accumulation and conversion curve) without substantial amounts of time, effort and mathematical ability.

References:
1Lieberman, S.V., JACS, 77, 1114-6 (1955); Parker, Dane Kenton, US 6355826 B1, Goodyear tire and Rubber Company.
2Stoessel, Francis; Thermal Safety of Chemical Processes: Risk Assessment and Process Design, Wiley-VCH, 2008, ISBN 3527317120, 9783527317127, pg257-265.

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Patricia Hicks
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