Short Path Distillation Grease

What is short path distillation (SPD)?

Short path distillation (SPD) is a method of separating compounds based on differences in their volatilities in a boiling liquid mixture under reduced pressure. This low-pressure technique uses multiple flasks and comparatively short extraction feeds to separate condensate media across paths of only a few centimetres.

Short path distillation is a relatively compact purification method that is ideal for laboratory applications where minimal instrumentation footprint is crucial. Conventional distillation methods often require much larger apparatus to achieve the requisite purity levels for application specific requirements. Short path distillation can achieve distillate purity levels of up to 99% using multiple components in a smaller space.

A typical example of short path distillation would be a distillation involving the distillate travelling from one glass bulb to another, without the need for a condenser separating the two chambers. It is often used for compounds which are unstable at high temperatures or to purify small amounts of compound. With short path distillation, the boiling temperature is reduced by lowering the operating pressure (i.e. working under vacuum). It is a continuous process with very short residence time. The advantage is that the heating temperature can be considerably lower (at reduced pressure) than the boiling point of the liquid at standard pressure, and the distillate only has to travel a short distance before condensing. A short path ensures little compound is deposited on the sides of the apparatus.

What is the best Apiezon short path distillation grease?

Apiezon PFPE 501 from M&I Materials Ltd is a high temperature vacuum grease that is the best choice when running short path distillation systems that require a high-temperature seal. This is because PFPE 501 is chemically inert, and offers effective sealing properties under extreme vacuum and temperature conditions. With an upper operating temperature of 250°C and vapour pressure of 1.3 x 10¹² at 25°C, PFPE 501 is robust, versatile and can be used for sealing and lubricating under the most extreme operating conditions. This includes environments where aggressive chemicals and strong oxidizing agents are regularly used.

High quality grease such as Apiezon PFPE 501 creates a tighter seal, protects your glassware and prevents pieces of expensive glass from getting stuck together. We know that Apiezon PFPE 501 has been used extensively in short path distillation systems. Used correctly our customers and our own laboratory tests report the grease is easy to apply and remove, does not creep, is not prone to leaks, can safely be used to temperatures up to 250ºC and lasts longer than other brands. The inertness of PFPE 501 allows adjacent molecules to pass by a thin layer without any interaction. This leads to reduced contamination in your system, as well as the compatibility of the grease with many types of materials.

There are short path distillation systems on the market that come with cheap PFPE and silicone based greases as standard. We also know first-hand that when using these products the systems can be vulnerable to leaks, creep leading to contamination, are not easy to disassemble and can get very messy! Our advice is buy cheap buy twice!