Autoclave safety requirements

With autoclave safety precautions, in a 6-liter stirred autoclave are placed 3000 gm of deionized and deaerated water, 3 gm of ammonium carbonate, 0.9 gm of methyl hydroxypropylcellulose (Methocel 65HG/50 cP from Dow Chemical Co.), and 3 gm of AIBN. The reactor is purged with nitrogen under a pressure of 10 atm. Then the reactor is evacuated, and 1500 gm of vinyl chloride is sucked into the autoclave. The autoclave is closed, and the agitator is started. The reaction mixture is heated to 65°C and maintained at 65°C by passing either hot or cold water through an external jacket as required. After approximately 2.2 hr, about 10% of the monomer is converted. 

The F value used in the design of a sterile cycle may greatly exceed the minimum F0 of 12. An F0 = 18 min will provide a 50% safety factor that will take into account additional time that may be required for steam to penetrate certain containers in middle or cool locations of the autoclave. 

Heat-stable solutions, rubber bungs and liners, bottles with plastic caps, ultrafiltration apparatus etc. are all sterilised by steam treatment at elevated pressure. Although the time required to sterilise is usually only about 15 min at 15 lb pressure the cycle time for modem autoclaves is several hours. This is because of the safety precautions built into these machines to prevent the doors being opened until the temperature of liquid within bottles has fallen to 80°C. 

Flow reactors offer considerable advantages over sealed autoclaves for supercritical reactions. Not only do flow-reactors require a much lower volume than a batch reactor for a given throughput of material (with obvious safety advantages) but also it is much easier to optimise reaction conditions in a flow reactor. We have already reported [4,5] the use of a miniature flow-reactor for the photochemical preparation of unstable metal complexes. We are now extending these techniques to the study of thermal and catalytic reactions. As an initial stage we... 

All solutions are required to be prepared with autoclaved ultrapure water (deionized water with a sensitivity of 18 MQ cm at 25 °C) and analytical grade reagents. Store the reagents as indicated. Conform to all waste disposal and safety regulations while preparing and disposing the materials. 

The gel fixing and treatment procedures can be carried out in any suitably sized glass or plastic dish, even the plastic lids from autoclavable pipette tip racks. No special equipment is required, but care should be taken to handle and dispose of radioactive solutions according to the appropriate safety regulations. 

To define the layers of protection proposed for a polymer autoclave to reduce the risk of exposing site persoimel to toxic vapors. To draw a risk reduction model incorporating the layers of protection and use the model to decide the required SIL for the safety instrumented system. ... 

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