The aftercare services and handlings measures are the most overlooked but critical aspect of manufacturing. Unfortunately, many industries lack the basic knowledge in this field and the services which can result in rendering the time, money and effort useless. Having said that, let’s take a step towards understanding the requisite processes.
DMSO Storage and Stability
Subsequent research has indicated that it is safe to store DMSO at room temperatures after large scale manufacturing. It is fairly stable while placed in contact with varying heat. Thus, it is denoted as thermally stable and can be heated up to a temperature point of 150 °C continuously for 24 hours without any noticeable degradation in its quality according to purity standards. When initially the package is received, it may arrive in solid-state, unlike the regularly available liquid state, however, the state of matter can be changed by warming the product to room temperature without any deterioration in the product.
However, heating the product for extensive leads to decomposition of the original chemical compound into methyl mercaptan and bis methylthio methane along with the release of pungent-smelling, poisonous gas. This breakdown is facilitated by acids and the counter-effect can be observed by the use of appropriate bases. While DMSO is stable up to 100° celsius when placed in alkaline, acid and neutral environments, however elimination of these can gear partial breakdown between 40 and 60°C resulting in observable alteration in physical parameters – viscosity, Density, Miscibility and Refractive Index.
Keeping all these factors in mind, it is recommended to store DMSO in sterile, impermeable, light resistant holders. For long term storage purposes, it can be mixed with water or dried through a molecular sieve. It is ideal to go for glass containers and avoid the usage of plastic as much as possible.
Methods of Purification
The manufacturing process of dimethyl sulfoxide primarily depends on one key material namely, Dimethyl sulfide. By the end of it the only contaminations accumulated is water with a small percentage of dimethyl sulfone. The Karl- Fischer test is put into use for determining the water percentages in the final sample.
For small – scale purification the sample is dried with Linde types 4A or 13X molecular sieve by extended exposure which is later distilled under low pressures. Alternative drying agents such as CaH2, CaO, BaO and CaSO4 can be used in case of unavailability to partially crystalline it.
On the other hand, voluminous purification calls for overnight standing of the mixture freshly obtained alumina in it’s activated state. Following which it is refluxed and dried with CaO and CaH2 for about 4 hours and finally distilled at low pressure. To speed up the process,it can be directly made to stand over a composition containing BaO, Alumina and CaSO4 and distilled over CaH2 used reduced pressure to obtain the final purified compound. Throughout all the above-mentioned processes, the temperature should be kept below 90°C to eliminate the chances of a disproportionation reaction. Since DMSO has the potential of reacting
with certain substances to create an outburst, close attention must be paid to the water removal and purification process to avoid mishap.
The Recovery process
DMSO recycling is an important step that needs to be taken into consideration for recovering the purified sample which can be aided by its unique properties. Dimethyl Sulfoxide being an excellent solvent and being easily soluble in water, benzene and toluene can be executed to segregate impurities which cut the cost. Ether extraction or reverse extraction can be used followed by vacuum distillation to obtain pure grade chemicals for use.
Once done with manufacturing, the above-mentioned processes need to be taken care of for increasing the shell life of DMSO while not compromising on the quality of product across sectors.