Working with DMSO

Every chemical is different and there are useful things to know when handling DMSO in an industrial setting.

Working with DMSO in cold climates. Pure DMSO has a melting point of 18.5°C (64°F). This is relatively high for a solvent and frozen DMSO must be thawed before it can be transferred.

When possible it may be best to arrange production schedules to handle DMSO during warm weather. If DMSO is used throughout the year at your facility, some simple handling guidelines for cold weather use are required.

Drum Handling

If possible, move DMSO drums / IBCs into a warm storage area several days before the date of intended use. It can take several days for frozen material to thaw.

If this is not practical, a band heater can be used to thaw DMSO drums. The use of such heaters is straightforward and they can be purchased from industrial supply companies.

McMaster-Carr, model 35275K31.
Thermalinc,  item #LIM-55.

When using band heaters, Gaylord recommends the use of 9 ½” wide Heaters with a 70° to 140° F Thermostat.  A built-in thermostat minimizes the potential for overheating, which can damage the drum and possibly lead to a fire.

Suitable heating bands should be approved for use with plastic drums, preferably have a non-adjustable thermostat, and have a recommended power output of 800W.

We recommend that the drums not be heated above a skin temperature of 110ºF. A typical HDPE the drums has a 225ºF temperature rating, but overheating can lead to DMSO decomposition. A typical thaw time is about 72 hours. Thawing time can be shortened when drums are stored on a pallet while thawing (not directly on a cold floor).

Glass bottles (1 and 4 liter)

The most practical way to thaw material at this scale is using warm water. A warm water bath maintained at 50°C should thaw the material effectively in 1-2 hours.

Although a lab oven could be similarly used, it is better to use warm water. It can be difficult to accurately set some ovens without calibration which might lead to overheating. There is also some risk that the bottle might break inside the oven.

An important suggestion is that the cap (and tamperproof seal) remain tight on the bottle during a thawing operation to preclude contamination by water. Additionally, it is recommended that the level of the bath water be lower than the cap during thawing. As an added precaution it is good practice to place the bottle in a sealable plastic bag to further protect it from water contamination when submersed for thawing.

ISO containers

ISO containers may be thawed using steam. The minimum temperature to heat DMSO should be 80ºF (27ºC) and the maximum temperature should be 110ºF (38ºC).

A DMSO ISO container will lose approximately 5-8 degrees per 24 hour period. As mentioned above, excessive heating can lead to DMSO decomposition. It is recommended that the internal temperature of the ISO container not exceed 110ºF (43ºC).

There are 4 longitudinal runs on an ISO that provide channels to heat the container.  The inlet and outlet connections are ¾” BSP fittings for connecting to steam supply hoses.  Do not trap steam when heating DMSO ISOs.  If product remains between the internal and external valve, it could be necessary to run a steam hose over the valve to thaw any frozen material.

Additives

Additives can sometimes be used to depress the freezing point of DMSO. Water is the most effective freezing-point depression additive. Freezing point data with respect to water concentration levels in DMSO can be found here in this resource.

For applications in which 10% water is acceptable Gaylord Chemical offers DMSO-LFP, an aqueous DMSO product which has a freezing point close to that of water itself.

In many applications, water suppresses the solvent properties of DMSO to an unacceptable extent. Alcohols (and conceivably any solvent capable of hydrogen bonding behavior) can also depress the freezing point of DMSO, but higher additive concentrations are required. Some data with a few such additives is given here in this resource.

Under no circumstances should containers of DMS (dimethyl sulfide) be heated.