小试叔丁基锂使用事故？ http://pubs.acs.org/isubscribe/j ... /html/8731sci1.html On Jan. 16, Sheharbano (Sheri) Sangji, a 23-year-old chemistry research assistant, died from injuries sustained in a chemical fire on Dec. 29, 2008, in a laboratory at the University of California, Los Angeles 在使用塑料针筒抽取 叔丁基锂 的过程中，由于未知原因推杆脱出，叔丁基锂喷出燃烧，并点燃了实验服。 aldrich推荐使用程序 Harran told Cal/OSHA and fire marshal investigators that the lab generally follows Aldrich Technical Bulletin AL-134 for handling air-sensitive reagents. The bulletin first recommends heating glassware in an oven to eliminate any adsorbed moisture, then cooling it in an inert atmosphere. Sangji refers in her notebook to using flame-dried flasks and the syringe found at the scene was plastic. Additionally, if a researcher is using a syringe to transfer the reagent, the bulletin says to use a 1- to 2-foot-long needle. The Cal/OSHA report says that Sangji’s was 1.5 inches. The Aldrich bulletin also recommends pressurizing the reagent bottle with high-purity dry nitrogen such that the pressure in the bottle pushes out the syringe plunger. “The plunger should not be pulled back since this tends to cause leaks and create gas bubbles,” the bulletin says. But Harran told fire marshal investigators that he prefers not to pressurize the bottle to push out the material. “I find that a little dangerous because then it can jump on you,” he told Aplin and Jurado. Harran said that he favors using a nitrogen line with a bubbler, under enough N2 pressure so that as he withdraws the syringe plunger to pull in reagent, the bubbler keeps going. “Aldrich recommends regulating the inert gas to about 3 to 5 psi to pressurize the bottle,” says Mark Potyen, a R&D scientist at Sigma-Aldrich. “Through a 16-gauge needle, the largest Aldrich recommends, the movement of the plunger is manageable and is a safer technique than pulling the plunger of the syringe to use the reduced pressure in the syringe to draw up the material.” This is partially why Aldrich recommends glass rather than plastic syringes, Potyen says, because pressure at 3 to 5 psi cannot push up a plastic syringe plunger. Aldrich also recommends using a syringe that is twice the volume that you intend to deliver and advises against reusing syringes for multiple transfers, Potyen says, since a dirty syringe could result in a locked-up barrel. For amounts larger than 50 mL, Aldrich advocates that researchers transfer the reagent by cannulating, or using a double-tipped needle to transfer the reagent under pressure from the bottle into a sealed graduate cylinder, then again from the cylinder into the reaction flask. 可能原因 Postdoc Ding noted that, when he first entered the lab, a reagent bottle was sideways and on fire—but he did not say whether that was the tBuLi bottle or the hexane flask. If it was the tBuLi bottle, and it was not clamped as specified by the Aldrich bulletin, it could have been a clue that perhaps Sangji, using a needle too short for the reagent bottle, had upended the bottle in one hand while trying to handle a 60-mL syringe with the other, and things went awry from there. Alternatively, although Harran told C&EN in an interview in May that he remembered that the bubbler on the nitrogen manifold was active when he later returned to the lab and shut down the experiment, he couldn’t recall if the port to the tBuLi bottle was open. Perhaps Sangji had simply forgotten to turn on the gas to the bottle, then pulled too hard on the syringe plunger, not realizing that she was fighting a lack of pressure in the bottle. Other possibilities include that the tBuLi reacted with moisture in the undried syringe, or with air that got into the syringe while Sangji was pulling up the reagent. Or Sangji was on her second or third transfer with a used syringe, it locked up, and she tried to release it. Last but not least, since she was using a 60-mL syringe for 50 mL or more of tBuLi, perhaps she simply overshot while pulling out the plunger查看更多10个回答 . 3人已关注
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