Overview

General Description

VAC Atmospheres glovebox is located in Birck 1077. The glovebox was inherited from the Prof. Don Bergstrom. It was not operational, and was extensively inspected and repaired before being put into use. The repairs included: (1) inspections and replacement of solenoid valves; (2) replacement of hose connections for gases; (3) installation of gas inlets and feedthrough; (4) replacement of the vacuum pump and vacuum tubing (oil free pump); (5) addition of a oxygen sensor, and (6) thorough cleaning. After three regeneration cycles, the glovebox was deemed operational. 

Introduction to the Glovebox

Glovebox is an instrument that allows convenient manipulations of materials in an atmosphere of an inert gas, most commonly nitrogen. Our glovebox is filled with Argon. The glovebox atmosphere is continuously circulated over a bed of catalyst which removes traces of water and oxygen. The catalyst is a combination of copper-based particles (that remove oxygen) and molecular sieves (that remove water). The catalyst needs to be regenerated periodically; this is done by a staff.

The glovebox is generally used for the manipulation of air- and water-sensitive materials. Manipulations inside the glovebox differ very little from their counterparts outside of it: handling of materials is done using thick butyl gloves and the common operations of stirring, weighing, and refrigerating materials can be easily reproduced. These gloves are the weakest point of the glovebox and its most common source of contamination, since it is very easy to introduce air into the glovebox through small incisions and holes in the gloves. These incisions can be made while handling sharp objects, like spatulas, syringe needles, scissors, etc. The gloves are much thicker than normal nitrile (or latex) gloves, so they will take some getting used to. To protect this "weak spot", wearing nitrile gloves is must over the butyl gloves!

In order to be able to work in the glovebox, you will need to bring materials and equipment into the glovebox without compromising its atmosphere. Consult the staff if you have any questions or doubts. Your only "gate" to the glovebox is the antechambers - large and small cylindrical assemblies on the right-hand side of the box. It has two doors - one that can be opened only from the inside of the box and one that can be opened only from the outside. These two doors should NEVER be open at the same time. Each antechamber also has two valves on it - one connecting it to the vacuum pump (antechamber vacuum valve), and another connecting it to the glovebox (this valve is the source of inert gas for the antechamber). These two valves should also NEVER be open at the same time.

The pressure of the inert gas within the glovebox should always be kept slightly above atmospheric pressure, to avoid contamination by back-sucking air into the glovebox. The glovebox regulates its pressure automatically. For quick manual adjustments of glovebox pressure, you can use its pedatrol - a foot pedal which is lying on the floor and which allows quick control over the glovebox pressure. If you see that the pressure is too high (it is easy to feel, gloves "oppose" you) press the left pedatrol button to decrease it ("low"). If the pressure is too low (gloves are hanging down or are sucked inside the box) then press the right button to increase it. Obviously, do not press both buttons at the same time. Actually, the pedatrol option is a seldom used. It is recommended just slow insert or extract the gloves to or out the box and the pressure will adjusted automatically.

Specifications

PURIFICATION: Mounted on the left side of box
• Single speed blower
• Single purifier
• Manual isolation valves
• Less than 1PPM O2, H2O
CONTROLS: 
• Automated: purifier regeneration, lab pressure, lab purge (manual
exhaust valve), system diagnostics
ANTECHAMBERS: Manual valves, Aluminum
• Mini antechamber - 5" dia.
• Main antechamber - 16' dia.  
VACUUM PUMP: dry pump
ANALYZERS: • Oxygen – LCD Display, optional audio alarm

Using the Glovebox: 

General Guidelines

1. The most obvious thing: NEVER put anything containing oxygen (closed vial would be a good example) or water/moisture into the glovebox.
2. ALWAYS report to a staff all significant events - oxygen content increase, bring large amount material, usage a new solvent, etc.
3. NEVER leave both the inner and the outer door to the antechamber open.
4. When in doubt - pump it out! If you are not sure whether your antechamber is under argon or air, ALWAYS pump it out. If you are not using it, leave the antechamber under vacuum.
5. When working with substances with very fine sizes, and you are afraid they could spill all over the place or mismanipulate, turn off the CIRCULATOR SWITCH during your manipulation. Make sure to turn it back on once you are done. You can unplug a blue 'fish tank' pump which circulate the glovebox atmosphere through the oxygen sensor. Make sure to plug it back on once you are done.
6. There is very little space available in the glovebox, and it must be used effectively. Each user should organize their own smaller sealed container to keep their samples in it. The user name, contact details and the date must be written on the container lid. Unidentified containers and materials will be thrown away. 
7. NEVER borrow things without asking.
8. Before putting your hands into the gloves, ALWAYS remove your watch, rings, and bracelets. This will minimize the risk of making holes in the gloves.
9. ALWAYS put on new clean nitrile gloves before you enter the glovebox gloves. The long sleeves are recommended too. The concern is purely hygienic. The atmosphere within the glovebox is about a few °C warmer than the outside (because of the circulator’s hot motor), so you will sweat. 
10. ALWAYS be mindful of the pressure. This is especially important if you are operating the antechamber or putting your hands in or out of the box. The pressure should not be too low (gloves sucked into the box), or too high (gloves sticking straight up from the box). Use pedatrol to adjust the pressure differences quickly; automatic pressure control will eventually kick in. If it does not, something is wrong: contact the staff immediately.
11. All vessels brought into the glovebox must be inert-gas-filled or evacuated before. If you do not do this, you will introduce air into the box. Make sure that all empty containers are open. When putting in a vessel with a solvent—especially a volatile one, like Et2O—or a solution, the stopper must be properly secured, even on flasks which were evacuated before. If not, it will very likely pop out and make a big mess in the antechamber. Use plastic clips and additional rubber bands to hold the stopper in place.
12. All solvents or solutions that you plan to put into the box must be dry and degassed.

13. The glovebox catalyst can be irreversibly damaged by thiols, amines, phosphines, alkyl halides, SO₂, SO₃, Hg, etc. You should avoid these materials in the glovebox at all cost. If you absolutely have to use them, ALWAYS discuss your experiment in detail with the staff before trying something potentially harmful.

14. In the glovebox, keep your samples open only when necessary. Do not leave any container of yours open in the box after you are done, to protect from unpredicted oxygen/water jumps due to a mistake during the introduction of materials, glovebox regeneration, etc. 
15. When you are done using the box for the day, ALWAYS clean the box up! Leave it in good condition, remove all your waste. The accumulated mess in the glovebox is really hard to clean.

Bringing Materials into the Glovebox

Introduction materials through the small and large antechambers is identical. The small antechamber is recommended if the size of material permits.

As the starting point (i) the antechamber should be under vacuum (see the vacuum gauge); (ii) all valves are closed; in the case of the small antechamber, the three-way valve in vertical position. When in doubt - pump it out! If you are not sure whether your antechamber is under argon or air, ALWAYS pump it out.  

1. Make sure that the antechamber inner door is closed.
2. If the antechamber is evacuated, close the valve to the pump.
3. 3. Open the nitrogen valve leading to the box slowly to fill the antechamber with nitrogen. Once
4. this is done (observe the pressure gauge), close the valve again.
5. 4. Open the outer door, place your materials onto the antechamber shelf, and close the outer
6. door again.
7. 5. SLOWLY open the antechamber vacuum pump valve.
8. 6. Place the antechamber under vacuum and keep it under vacuum for at least 20 minutes. If you are bringing in a lot of material, extend this time to 30 minutes. If you are bringing in very porous materials—paper, cork rings, kimwipes, etc.—you first evacuation cycle must last overnight.
9. 7. Close the antechamber pump valve and slowly fill it with nitrogen again.
10. 8. Repeat steps 5–7 two more times.
11. 9. Put your hands into the gloves, open carefully the inner door, and bring in your materials.
12. 10. Closetheantechamberinnerdoor.

Bringing Materials out of the Glovebox

1. 1. Make sure that the antechamber is under nitrogen. If you are not sure about this, you must evacuate the antechamber and then refill it with nitrogen. Do not make any assumptions!
2. 2. Open the inner door, put your stuff in, and close the inner door tightly.
3. 3. Make sure that the valve leading from the antechamber to the glovebox is closed. Make sure
4. that the antechamber vacuum valve is closed too.
5. 4. Open the outer door, remove your stuff, and close the door again.
6. 5. Slowly open the antechamber vacuum valve. Leave the antechamber under vacuum.

Catalyst Regeneration and Atmosphere Testing

The inert atmosphere in glovebox is purified by circulating it through a catalyst bed (also known as DRI-TRAIN). The catalyst bed contains a copper-based oxygen-reducing agent and molecular sieves to remove water. The catalyst bed needs to be regenerated periodically, depending on the usage and on the types of materials that were used in the glovebox. This period is typically on the order of 3–6 months. Catalyst regeneration is performed by: (a) isolating the catalyst from the glovebox, (b) exposing the catalyst to a stream of hydrogen and heating it, (c) evacuation of the catalyst, and (d) refilling of the catalyst with inert gas and reconnecting it to the box. The mixture of 5% H2 in N2 (uncertified) is used as a regeneration gas. One full tank is roughly enough for two regeneration cycles. During the regeneration, the chemically bound oxygen is released as water and expelled from the catalyst bed—together with the moisture released from the molecular sieves—through the stream of the regeneration gas. The full regeneration cycle takes about 12 hours: it should be started early in the morning and closely followed until the evening. Do not perform the regeneration process overnight!

Questions & Troubleshooting

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References