Introduction Organometallic reagents are widely used in organic synthesis. Typical applications include their use as strong bases, as nucleophiles, in metal exchange reactions and as reducing agents. Examples of such reagents include Grignard reagents, organolithiums, organozincs and lithium amide bases. All of these reagents react readily with moisture, oxygen or both so they must be protected under an inert atmosphere. Historically, researchers who require organometallic reagents for synthetic purposes have chosen to freshly prepare these reagents, often in-situ, and use them immediately. However, safety concerns due to the highly reactive nature of these reagents, as well as a continuous push to reduce time-to-market, have led researchers to purchase commercially available organometallic reagents.
For commercially available organometallic reagents, a key concern for researchers, buyers and stockroom managers alike is how long the reagent can be stored without significant decomposition. Since these reagents are generally consumed over a period of time, the packaging system becomes even more critical. AcroSeal packaging is specifically designed to maintain the integrity of air- and moisture-sensitive reagents while providing a convenient, easy-to-use and safe means of storing and dispensing research quantities. Key Features of AcroSeal Packaging Septum AcroSeal packaging uses specially designed multi-layer septa. The AcroSeal septum used for organometallic reagents consists of a double sandwich—an inner PTFE layer that is in contact with the reagent and an outer butyl rubber layer. The thickness of the septum is double that of typical competitor brand packaging, providing improved mechanical performance during needle puncture. The inner PTFE layer is inert to the reagent and ensures that the reagent is uncontaminated with the septum material. The thick outer butylated rubber layer allows for excellent re-sealing around needle punctures.
Repeated punctures to a septum in the same spot over time increase the risk of deformation and the likelihood that the septum will not re-seal. With competing brand packaging, it is very difficult to avoid repeated punctures in the same spot due to the very limited septum surface area. The AcroSeal septum provides more than 15 times this surface area, allowing broader spread for needle punctures, leading to better re-sealing over a longer time period. Bottle Closure System The AcroSeal closure system features a quadrant-style cap design that holds the septum in place, reducing the risk of bulging or deformation. A cushioned liner in the external cap presses against the septum and quadrant cap on closure, thus creating a secondary seal which prevents ingress of moisture and oxygen from the atmosphere. The tamper-evident seal, which breaks with the first opening of the cap, is used as a visible indicator of an unopened bottle. The AcroSeal screw closure not only allows syringe withdrawal of the reagent through the septum, but provides the added convenience of permitting the top to be unscrewed and larger volumes to be poured from the bottle, which may then be closed by screwing the lid back onto the bottle.