{"id":386066,"date":"2026-04-07T09:06:10","date_gmt":"2026-04-07T09:06:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/386066\/"},"modified":"2026-04-07T09:06:10","modified_gmt":"2026-04-07T09:06:10","slug":"how-to-choose-reactor-materials-and-test-for-compatibility-business","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/386066\/","title":{"rendered":"How to choose reactor materials and test for compatibility | Business"},"content":{"rendered":"

Choosing a reactor made from the wrong materials can be a costly and potentially dangerous mistake. And with chemistry constantly evolving, testing for material incompatibilities can always throw up new surprises.<\/p>\n

Eric Margelefsky and colleagues at Merck & Co in Rahway, US, have published a guide to Merck\u2019s strategy for evaluating materials compatibility<\/a>, along with guideline acceptance criteria.<\/p>\n

\"Hastelloy<\/p>\n

\u2018There\u2019s always new reagents,\u2019 says Margelefsky. \u2018We\u2019ve seen really interesting cases where a solvent is completely inert to a metal, and a certain acid is also pretty inert to that metal, but then you mix them together, and all of a sudden the metal just gets eaten away,\u2019 he shares.<\/p>\n

For small-molecule active pharmaceutical ingredient manufacturing, shared-use facilities are the norm, which means using pre-existing reactors and equipment of various materials. It\u2019s therefore important to know that the proposed chemistry isn\u2019t going to damage the apparatus.<\/p>\n

When new equipment is being purchased, material choice becomes a balance between cost and versatility. \u2018It becomes a business decision,\u2019 explains Margelefsky. \u2018Getting something that is highly chemical resistant often costs more money.\u2019<\/p>\n

There can also be deadly consequences to material incompatibilities in industrial settings. When the metal of industrial equipment corrodes, it weakens and can fail with little warning. Metal corrosion can also release flammable gas, leading to explosions and fires.<\/p>\n

Even small amounts of unexpected metal ions in pharmaceutical streams can cause problems. The scientists give two real examples from Merck: when transition metal ions formed from corrosion caused a chiral hydrogenation to generate a racemic product, and when a small amount of iron from corrosion led to a purple product instead of the expected white.<\/p>\n

To avoid incidents like that, Merck uses two methods to evaluate metal corrosion: immersion studies and electrochemical corrosion studies.<\/p>\n

\"Metal<\/p>\n

In an immersion study, a rectangular coupon of the metal is suspended via Teflon tape in the liquid stream for up to 14 days. The coupoin might be part-or fully submerged, and the solution may be heated or stirred, depending on the process being investigated. At the end, the metal coupon is weighed, microscopically examined, and a corrosion rate is calculated. The liquid phase may also be analysed to identify and quantify any corrosion products.<\/p>\n

In an electrochemical corrosion study, a disc-shaped sample of the metal is used as the working electrode in a flat cell apparatus. \u2018Fundamentally, what\u2019s happening is, as the solution attacks the metal, the metal is dissolving into solution, and electrons are being released,\u2019 explains Margelefsky. \u2018So, by measuring the current, you\u2019re directly detecting the amount of corrosion by detecting an electronic flow, which is just so cool, when you think about it.\u2019<\/p>\n

While electrochemical corrosion studies are significantly quicker \u2013 taking hours instead of weeks \u2013 they only work in aqueous solutions, and immersion studies are simpler to perform and interpret. \u2018It seems like, intuitively, you\u2019d be using electrochemical methods for most of that quick assessment \u2026 but in practice the coupon studies are actually pretty easy,\u2019 says Margelefsky. \u2018You drop the coupon in, you come back to it a week or two later, and you do the analysis. There\u2019s not actually that much interactive work needed, and it\u2019s pretty unambiguous.\u2019<\/p>\n

\u2018The gold standard is just to do a coupon study, and we\u2019ve been supplementing that with electrochemical studies where needed or where possible,\u2019 he says.<\/p>\n

Plastics<\/p>\n

Polymer compatibility studies are generally similar immersion tests, but samples are also tested for hardness using a durometer, both in wet (just out of the solution) and vacuum dried conditions.<\/p>\n

\"Metal<\/p>\n

An extra consideration when working with polymers is UV exposure. While it isn\u2019t generally an issue for equipment used inside, \u2018in an industrial setting, you have things that are stored outdoors,\u2019 says Margelefsky. \u2018When people think of a factory, they think of everything being enclosed, but the reality is \u2026 a lot of processing facilities are largely open.\u2019<\/p>\n

Glass<\/p>\n

Glass is integral at every step of the development process, from beakers and scintillation vials to commercial-scale glass-lined reactors. Like plastics, glass is tested by immersion studies.<\/p>\n

\"Borosilicate<\/p>\n

Any changes to a glass surface inhibits its ability to be cleaned, which can lead to contamination both from reagents and from the cleaning equipment. For glass-lined reactors, damage to the lining could expose the metal, leading to further corrosion or contamination.<\/p>\n

Glass equipment can also fall victim to static discharge. As a solvent with low conductivity is pumped through non-conductive lines or otherwise agitated, it can build up a strong static charge. \u2018It will eventually reach a voltage where it will spontaneously discharge through the nearest path,\u2019 Margelefsky explains. \u2018In the case of our thin glass-lined vessels, the shortest path is just to drill a hole through the glass. And so that\u2019s what you end up seeing, these little pinholes, which are expensive and time-consuming to repair.\u2019 Such electrical discharges also present ignition hazards if the reactor atmosphere is not sufficiently inert.<\/p>\n

What can bench chemists take away from this?<\/p>\n

Chemjobber, a Chemistry World contributor and US-based process chemist, believes that the paper will be a useful resource for academics interested in industrial chemistry. \u2018There definitely are principles that graduate students and bench chemists can use,\u2019 he says. Most importantly realising that metals and glass are definitely not inert and that corrosion will happen, but also that it\u2019s possible to identify and quantify corrosion products that end up in reaction mixtures or products.<\/p>\n

\"Stainless<\/p>\n

\u2018This article is a demonstration of how good you can get with unlimited resources,\u2019 says Chemjobber. \u2018Chemists at smaller organisations that are thinking about these programmes now have a glimpse as to how to attack this systematically and\/or quantitatively.\u2019<\/p>\n

While not everyone has access to the laboratories and resources of Merck, some of these tests aren\u2019t difficult to usefully replicate, says Margelefsky. \u2018We have microscopes, we have the electrochemical things, but anybody could get some metal coupons and do some simple studies. You can get a lot of information out of that, even if you don\u2019t have all of the advanced equipment.\u2019<\/p>\n

He has two pieces of advice for chemists working at the lab scale. \u2018The biggest thing is just to pay attention. Once you know that there\u2019s certain materials that might be incompatible with your reactors, keep an eye out for that before you start to scale something up \u2026 if you\u2019re using more expensive equipment, pay attention before you start to damage it.\u2019<\/p>\n

\u2018The other is to keep your eyes open. If you run an experiment and you notice that the vial is etched and hazy afterwards, don\u2019t just ignore that information, especially if you\u2019re planning on scaling up to a much larger, much more expensive glass reactor.\u2019<\/p>\n","protected":false},"excerpt":{"rendered":"Choosing a reactor made from the wrong materials can be a costly and potentially dangerous mistake. And with…\n","protected":false},"author":2,"featured_media":386067,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[61,60,80],"class_list":{"0":"post-386066","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-technology","8":"tag-ie","9":"tag-ireland","10":"tag-technology"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/386066","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=386066"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/386066\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/386067"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=386066"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=386066"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=386066"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}