The uncatalyzcd intramolecular [4+2]cycloaddition of 2E,TE,9(E)-decatrienoates, conducted at 140 oC in a medium of smectic liquid cryctals proceeds with a remarkably high level of chendcai efficiency and diastereselectivity, in contrast to the isotropic phase reactions which result in much lower yie
Can solvent choices enhance both process safety and efficiency?
β Scribed by Skip E. Evon; Sima Chewin; Glenn T. Bodman; Anthony J. Torres
- Book ID
- 105358902
- Publisher
- American Institute of Chemical Engineers
- Year
- 1999
- Tongue
- English
- Weight
- 390 KB
- Volume
- 18
- Category
- Article
- ISSN
- 1066-8527
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
Recent work has demonstrated that the decomposition characteristics of individual chemicals ae often subsrantially different from those of the same chemical when combined with a solvent. Further, different solvents alter the decomposition in significantly different ways, shifting the observed Differential Scanning Calorimeter (DSC) onset and peak temperatures and maximum rates to lower as well us higher values. Often the magnitude of these effects cannot be explained as the result of simple dilution. This prior work with energetic materials in solvents emphasizes the importance to process safety of systematically testing reaction mixtures, in addition to testing individual chemicals.
The primary focus of such testing is to ensure the hazards of the proces are well understood so that the pmcess can be modified, or additional necessary preventative and protective systems can be implemented to minimize process upsets. However, it is demonstrated here that this knowledge can also be leveraged to modify processes to substantially increase process efficiency while maintaining or enhancing safety. for example, the batch size of an existing process had been very restricted because of the potential severity of a thermal runaway.
Research on chemisty/solventβspecific decomposition data was utilized to select candidate replacement solvents for process optimization. A cooperative effort by safety engineers and development chemists ensued, resulting in a final process that entirely eliminated the batch size restrictions while simultaneously reducing reaction time and improving quality.
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