How to perform a reaction at one kilogram of pressure

If the quantity isn’t too large, can we replace stirring with shaking? If there are any good instruments, let me mention them here

But what is needed is a four-necked flask, a thermometer, and rubber stoppers for the several holes; unfortunately, these cannot withstand the pressure, as operations must continue immediately after the pressure is applied

Isn’t one kilogram of pressure (approximately equal to) one atmosphere? How is it possible not to be able to bear it?

Or rather, it should be an additional one kilogram of pressure

Have you tried it? As it is stated below, “But with four flasks and rubber stoppers, they definitely won’t be able to handle the pressure, and mixing might also cause leaks.” You haven’t done it yet; wrap the rubber stopper with tape, and it should be fine. Give it a try first – you can use a nitrogen tank without any sample

The poster is probably referring to a gauge pressure of 1 kilogram; ordinary glass four-neck flasks certainly cannot withstand such pressure. The poster can contact Hengda Chemical Instrument Factory in Weihai City, Shandong Province, to purchase a laboratory high-pressure reactor. Another link: http://www.baidu.com/s?wd=WFD3030 This post was last edited by Canghai Yili Sha on 2009-4-11 08:59]

Cang Ban is right. I have seen similar pressure tests using copper flasks, and the stoppers used to hold the thermometers are also of the type with screw caps. It should be the pressure reaction vessel mentioned by Cang Ban.

With a gauge pressure of 1 kilogram, glass containers certainly cannot withstand it; it is recommended to use metal containers instead.

Without a sense of safety, glass instruments cannot be used for experiments under pressure (except those that have been specially processed), as this can lead to explosions and flying debris that may injure the experimenters. There are many market autoclaves; you’ll find a huge number of them if you search on Google.

It can be made using metal containers; the type of metal to use depends on the properties of your material. You could consider making it with a flat bottom, and magnetic stirring can be used for mixing, which solves the problem of sealing during mixing. I have done this before – several holes can be made in the bottle, and sealing isn’t an issue at all. With just 1 kilogram of pressure, there’s no problem whatsoever. Of course, it’s necessary to analyze each specific situation; it’s quite difficult to observe reactions in real time. This post was last edited by alkoxysilane on 2009-4-11 09:40]

For reactions under such pressure, steel reactors should be used; there are several specialized manufacturers in China at present

1 kilogram of gauge pressure is only considered to be in the low-pressure range; it’s determined by how much pressure glass products can withstand. Please check the technical specifications for that flask. Using a high-pressure reactor would be a waste, as the metal reactor might not even be resistant to the corrosion caused by the materials being tested. Additionally, a experiment should have a complete list of equipment; following the instructor’s instructions should be sufficient, without the need to look up the technical specifications of flasks.

With a gauge pressure of 1 kilogram, glass containers certainly cannot withstand it; it is recommended to use metal containers instead.

Seeing this topic, I think the young people are truly impressive! First of all, I would like to say that I conducted experiments using a 500-milliliter flask to test its ability to withstand a pressure of one kilogram. At that time, the rubber stopper was secured to the mouth of the flask with wire, and the stirring was done using a mercury-studded stirrer sleeve, which was also fixed to the flask’s mouth with wire. Of course, no mercury was used for sealing; instead, thick rubber hoses were employed for sealing. It’s important to note that internal sealing within the flask was also achieved using rubber hoses. I think it’s fine to use a standard flask of 500 milliliters or less for testing under one kilogram of pressure. There are also many examples in real life of glass withstanding pressure; for instance, water bottle liners, which are hollow (with a vacuum level of 1 kilogram), yet can still withstand atmospheric pressure ； Furthermore, high-pressure mercury lamps are also glass products with internal pressure. However, I would like to emphasize that in our time, the conditions were limited, and there was not enough emphasis placed on safety. From a safety perspective, I do not recommend doing this, as there are many autoclaves used in laboratories these days, and a laboratory can easily purchase one.

I used autoclaves for my fire-related experiments in the past; they are widely available on the market and their technology is quite mature. Glass containers generally cannot be used when pressure is involved

I’ve also bought a small pressure gauge now. I’m planning to use a 250ML glass four-port flask; the one from Shenbo. Magnetic stirring will be used, but it’s necessary to control the temperature, so that idea has been abandoned. Now, for the four ports: one is for stirring, one for the pressure gauge, one for the thermometer, and one for the burette. All I can do now is tie things together with ropes. Since the solvent is acidic, metal components might not be suitable. Additionally, it’s not convenient to observe the reactions if metal is used. Ah, this is tricky

Glass bottles can handle reactions with a gauge pressure of 0.1 MPa; if the flask is of high quality, a pressure of 0.3 MPa can also be achieved. We generally use hollow plugs with ground ends, but both the hollow plugs and flasks are custom-made. At 0.1 MPa, it’s sufficient to tie the flask and the hollow plug together with a rope; this usually meets the requirements. To achieve 0.3 MPa, it is necessary to have a rope tie at both the flask and the stopper, which provides greater stability. Ordinary glass bottles can withstand a pressure of 0.1 MPa without any problem. It is best to have it custom-made if the pressure exceeds this level. Using an autoclave at such a low pressure is not effective. Special attention must be paid to stirring in glass bottles during reactions under pressure to ensure no air leakage (we generally use magnetic stirring; secondary metal stirring is employed when high viscosity and temperature requirements exist).