Evaporator Ebook 2017

1 Lab Manager’s Product Resource Guide: Evaporators Rotary Evaporators: Must Have Features 2 Angelo DePalma PhD Choosing the Best Evaporator For Your Application (Video) 4 Lab Manager Tips for Choosing an Evaporator for Your Lab 5 Ryan Ackerman Reducing, Distilling, Recycling and Concentration 7 Angelo DePalma PhD Selecting a Vacuum Pump for Rotary Evaporation (Video) 8 Lab Manager All-in-One Versions and Other Options to Enhance Efficiency 10 Mike May PhD Nitrogen Evaporators: Making Concentration Easier & Greener 12 Mike May PhD Evaporator Product Finder 15 Lab Manager Manufacturer List 15 2 Rotary Evaporators: Must-Have Features Rotary evaporators, or “rotovaps,” may be found wherever processes require sample concentration or solvent distillation. By Angelo DePalma PhD Rotary evaporators are standard laboratory equipment found in nearly all laboratories. Chemical, pharmaceutical, food, and environmental industries are the most common users, but rotary evaporators, or “rotovaps,” may be found wherever processes require sample concentration or solvent distillation. All rotary evaporators include a heating bath, condenser, collecting vessel, and rotating sample or distillation flask. BUCHI Corporation (New Castle, DE), a leading manufacturer of rotovaps, still sells a large number of those simple units to academic and even industrial labs. But another world of rotary evaporation exists for laboratories that value application versatility, automation, and connectivity. “Our largest-volume market has been and remains pharmaceuticals, and they’re willing to pay for a high degree of automation, for many features that go beyond simple rotovaps,” says Jason Wagner, VP of marketing at BUCHI. “But there’s still a big market for stripped-down, no-frills models.” 3 A “full system” has a chiller to replace the use of cold tap water in the condenser unless dry ice is readily available. In place of the simple aspirator or house vacuum you may now be using, you could enjoy the benefits of a real vacuum pump, which is chemically inert and quiet. Worried about samples bumping into the condenser and collection vessel? A vacuum controller will solve that problem without the user having to give it a second thought. Unlike with some laboratory products where purchasers must outsource upgrades and modifications, top rotovap vendors supply all the necessary components. Since modern rotary evaporators operate at up to 5 L at benchtop scale and at 20 to 50 L for industrial models, general solvent recycling becomes an attractive alternative to dedicated distillation systems. Low-temperature condensation traps even volatile solvents like ether and methylene chloride, while high vacuum enables recycling of polar aprotic solvents like dimethylformamide or distillation of essential oils. Every user of rotary evaporators has experienced bumping. Vacuum controllers virtually eliminate such mini-disasters by allowing a vacuum gradient. “That’s where automation really comes in,” Wagner says. “The controller and AutoDest sensor measure whether the condenser is heating and adjust vacuum accordingly.” Similarly, a foaming sensor can tell whether the distillation is getting out of control. “And all the user has to do is say go.” The wide variation in features and price and the low potential dollar entry point for rotary evaporator acquisition are somewhat unusual in the world of laboratory equipment. Yet despite the lingering fondness for simple rotovaps, nearly every laboratory can benefit from automation, says Thomas Ketterer, head of application support at IKA Works (Staufen, Germany). “The reasons are enhanced safety, the capability for unattended operation, consistency of conditions, and results.” A call for simplicity? Jim Dawson, president of Heidolph North America (Elk Grove Village, IL), believes that automation may be overhyped. “Researchers want to be able to run their processes uninterrupted but to get involved easily if the need arises. Chemists are hands-on, highly visual types of researchers. They may wish they could walk away from what 4 they’re doing completely and still achieve the desired result, but they don’t do that in practice. They want simplistic automation, not something complicated. They want automated vacuum control and measurement, and want to know that when the evaporation is completed the flask will come out of the bath, but it has to be simple. And they don’t want to spend a lot of money on it if they don’t have to.” The ability to have many options at varying price points is a hallmark of rotary evaporators. “Chemists don’t want to be boxed in to one level of sophistication; they want to pick and choose specific options and do that with an associated price as well,” Dawson says. Choosing the Best Rotary Evaporator for Your Application Join Linda the lab manager and her team as they explore what some of the features to consider when purchasing a new rotary evaporator for your lab. Watch Video 5 Tips for Choosing an Evaporator for Your Lab As it does with most lab instruments and equipment, the sample plays a major role in which evaporator will be best for your lab How will sample type affect which evaporator is ideal? The sample in question will play a key role in the evaporator setup. For example, if acids are being used, the system must be properly coated to prevent corrosion (especially on the pump), and will need proper ventilation. Solvents can damage rubber and plastic components, and should be protected against as well. Another important consideration is that different samples are condensed at different temperatures, and may require different cold traps: typically a -50°C cold trap is ideal for aqueous-based samples, a -85°C cold trap traps most solvents, and a -105°C cold trap is recommended for alcohols. 6 How are safety concerns addressed for evaporators? Due to the nature of heating up aqueous samples, acids, and solvents, a variety of safety accessories can be used to ensure the safety of the operators. As glassware is under extreme pressure due to the vacuum pump as well as being heated, coated glassware can be used to ensure flasks don’t shatter during operation. Shields and protective hoods with ventilation can also help ensure operator safety. Some manufacturers offer advanced options, such as motorized lifts and shutoff procedures for power outages or if the heating bath goes dry. What environmentally friendly options are available for evaporator usage? For the condensing and collection of samples, many options exist. Condenser coils or cold fingers are generally paired with circulating tap water or dry ice. While these methods are adequate for the purpose, constant changing of water to prevent algae buildup can get wasteful, along with a constant need for dry ice. Many manufacturers now offer circulating chillers which can be attached to evaporators, allowing for highly efficient condensation without the waste associated with using tap water or dry ice. 7 Reducing, Distilling, Recycling, and Concentration. Rotary evaporators have for decades been staples in labs and industries performing chemistry By Angelo DePalma PhD Key applications include sample concentration, solvent recycling, extractions, and separation of solvent mixtures In their simplest embodiment, “rotovaps” consist of a temperature bath, rotating flask, condenser, collection flask, and vacuum source. Solvent distills from the sample under the combined effects of heat and vacuum, and collects after condensation in the collector. Recovered single-phase organic solvents may be dried and re-used; binary, tertiary, or quaternary solvent mixtures are also re-used but may need adjustment for composition. Water is the fluid of choice for the bath, but some laboratories use oils to reach heating temperatures of up to 180°C. Several choices are available for the condenser coolant. Until about 10 years ago, almost everyone used house water. Concerns over water consumption caused many labs to switch to a chiller to recirculate coolant into and out of the condenser coils. Chillers provide more precise cooling, greater control over 8 condensation, a greatly reduced environmental footprint, and are overall less expensive to use than water. High-efficiency trapping of low-boiling solvents is achieved with a “cold finger” charged with dry ice and acetone. Vacuum options Of all the rotovap options, vacuum is probably the broadest. At one time, water aspirators were the most common vacuum sources. That practice has gone by the wayside for the reasons given for water coolers and due to environmental concerns related to solvent vapors venting down the drain. The next most common source is house vacuum, which is limited but inexpensive and reliable. Users typically insert a Woulff bottle or cold trap between the vacuum spigot and the rotovap, to trap volatiles that the condenser missed and protect the house vacuum system. Increasingly, users employ vacuum pumps to achieve reproducible and rapid solvent removal. The vacuum must be applied carefully, however, to avoid bumping and foaming. Traditionally, vacuum control was achieved by slowly closing a glass stopcock. Increasingly, users are turning to more sophisticated vacuum control, which Kristof O’Connor, product manager at Heidolph Brinkmann (Elk Grove Village, IL), describes as “probably the number-one improvement in rotary evaporators over the past two decades.” Control became necessary, he says, because “vacuum pumps are very stupid machines. They try to achieve as high a vacuum as they can, as quickly as possible,

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