tag:blogger.com,1999:blog-8964719845369935777.post6833804642479339070..comments2024-03-29T09:05:29.819-04:00Comments on Chemjobber: Process Wednesday: It's not just the organic chemists who have issues scaling upChemjobberhttp://www.blogger.com/profile/15932113680515602275noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-8964719845369935777.post-45739289873526553932013-07-24T16:25:10.497-04:002013-07-24T16:25:10.497-04:00I have to disagree. Polymers are large enough that...I have to disagree. Polymers are large enough that they are inherently nonisotropic at any scale where small molecules are isotropic. Therefore the mechanical properties do depend on the processing, and the processing depends on the scale of the equipment. Johnhttps://www.blogger.com/profile/04412324900423436763noreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-50981338085357658292013-07-24T15:40:19.129-04:002013-07-24T15:40:19.129-04:00Well certainly the physical properties are "t...Well certainly the physical properties are "technically" always inherent and largely invariant (and would make same statement for polymers) but as suggested from "practical" perspective it matters greatly and therefore from that angle equipment and handling always is an issue in chemical scale-up and not exclusive to polymers (which could by their nature include less simple or obvious resolution options).Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-78532720178377537342013-07-24T13:16:51.467-04:002013-07-24T13:16:51.467-04:00Perhaps it was written unclearly. Yes, there's...Perhaps it was written unclearly. Yes, there's a qualifier in there. <br /><br />(But even on plant scale, the physical properties are the same (i.e. this reagent is really thick) but the transfer problems are much worse, yes?)Chemjobberhttps://www.blogger.com/profile/15932113680515602275noreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-76269845895401083492013-07-24T13:04:49.815-04:002013-07-24T13:04:49.815-04:00We used to have a large benchtop twin screw extrud...We used to have a large benchtop twin screw extruder in my grad lab, although the group's focused had changed so almost no one used it.<br /><br /><br />A scale up danger in the synthesis of polymers is the autoacceleration effect possible in free radical polymerizations.<br /><br />http://en.wikipedia.org/wiki/Autoacceleration<br /><br />I've had this happen on the scale of a few grams of acrylate monomer during my time working on RAFT polymerizations. My supervisor used to tell us that when you get up to larger scales you can possibly blow up a fumehood.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-63211275017854974392013-07-24T12:49:30.933-04:002013-07-24T12:49:30.933-04:00If you have done much crystallization and isolatio...If you have done much crystallization and isolation's or transfer of viscous reagents at large scale not sure could say readily agree "classic old-skool chemical manufacturing; the physical properties of a compound are the same at bench scale or at plant scale" (unless that is included in your qualifier "for the most part").Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8964719845369935777.post-1153592804676053282013-07-24T12:19:59.922-04:002013-07-24T12:19:59.922-04:00I like this article. I've been a strong advoca...I like this article. I've been a strong advocate of moving "structure-property" relationships to "structure-processing-property" relationships with polymers. The example I typically use is polystyrene disposable cutlery vs styrofoam cups. Both are the same materials, processed in different ways providing different properties.<br /><br />This doesn't get away from the scaling issue, but there are a lot of cool polymers that are synthetically generated and characterized, but never put in any sort of (semi-)realistic processing scenario that can enhance (or degrade) the interesting properties.Polychemhttps://www.blogger.com/profile/11318163213252728838noreply@blogger.com