For example, organometallic compounds usually contain a metal or metalloid bonded directly to carbon. Inorganic chemists are employed in fields ranging from mining to microchips. Their work is based on understanding:. Many inorganic chemists work in industry, but they also work in academic institutions and government labs. Inorganic chemists who work in government say their time is increasingly spent writing grant proposals and competing for research money.
Inorganic chemists compare their jobs to those of materials scientists and physicists. All focus on exploring the relationship between physical properties and functions.
But an inorganic chemist is more concerned with these properties at the molecular level. Inorganic compounds are used as catalysts, pigments, coatings, surfactants, medicines, fuels, and more. They often have high melting points and specific high or low electrical conductivity properties, which make them useful for specific purposes.
For example:. Collaborate with other chemists, keep up-to-date with new developments in the field and stay connected to your community. Careers Launch and grow your career with career services and resources. Communities Find a chemistry community of interest and connect on a local and global level. Discover Chemistry Explore the interesting world of science with articles, videos and more. This group is highlighted in Fig.
The first number refers to the diamine and the second one refers to the diacid. This increases the spacing between the amide groups, resulting in decreased mechanical properties and melting point. Nylon 6 and other nylon polymers that contain only a single number in the name are made in a completely different manner. In these cases a single chemical is used that has a ring structure and contains both of the chemical groups needed to produce the amide functionality.
Figure 3 shows the chemical reaction used to produce nylon 6. Note that this repeating unit also contains six carbons, five that are attached only to hydrogen while the sixth one is part of the amide group.
While they can be combined to produce a wide range of properties, they cannot be converted into one another. Right now everyone is talking about nylon The shortage in the world market was caused by an explosion at a plant that makes a chemical known as cyclododecatriene CDT.
Through a series of chemical reactions, CDT, a carbon ring structure, becomes a chemical known as laurolactam, a carbon ring with the same amide functionality built into it that is contained in caprolactam.
But when nylon 12 is made, the amide groups are twice as far apart as they are in nylon 6. But more importantly this material is much more flexible so that it can be made into hose, tubing, and even balloon catheters.
Easy, right? Obviously not. The automotive industry summit meeting in Detroit in mid-April to discuss the nylon 12 shortage was not convened because this is going to be simple. And while automotive is getting most of the attention in the press, it will be medical device suppliers that get to stand first in line when the limited supply is doled out.
If other nylons do successfully stand in for nylon 12, nylon 11 makes the most sense but is also in short supply it will be due to a combination of skillful manipulations of chemistry coupled with tough decisions about design, processing, and even the consequences of using additives to optimize performance.
The long chains break and you can eventually end up with the original monomers - hexanedioic acid and 1,6-diaminohexane. Because you produce small molecules rather than the original polymer, the fibers are destroyed, and you end up with a hole! Jim Clark Chemguide. What are polyamides? An amide link has this structure: In an amide itself, of course, the bond on the right is attached to a hydrogen atom. Nylon In nylon, the repeating units contain chains of carbon atoms. Nylon-6,6 Nylon-6,6 is made from two monomers each of which contain 6 carbon atoms - hence its name.
The diagram shows the loss of water between two of the monomers: This keeps on happening, and so you get a chain which looks like this:. Nylon-6 Iit is possible to get a polyamide from a single monomer. Kevlar Kevlar is similar in structure to nylon-6,6 except that instead of the amide links joining chains of carbon atoms together, they join benzene rings.
Making nylon-6,6 Nylon-6,6 is made by polymerising hexanedioic acid and 1,6-diaminohexane exactly as shown further up the page. Oxidation of the cyclohexane opens the ring of carbon atoms and produces a -COOH group at each end. That gives you the hexanedioic acid. Some of that can then be converted into the 1,6-diaminohexane. The acid is treated with ammonia to produce the ammonium salt. This both dehydrates the salt and reduces it to the 1,6-diaminohexane.
Making nylon-6,6 in the lab In the lab, it is easy to make nylon-6,6 at room temperature using an acyl chloride acid chloride rather than an acid. Hydrolysis of polyamides Simple amides are easily hydrolysed by reaction with dilute acids or alkalis. Uses of polyamides Nylon: Apart from obvious uses in textiles for clothing and carpets, a lot of nylon is used to make tire cords - the inner structure of a vehicle tire underneath the rubber.
The fibers are also used in ropes, and nylon can be cast into solid shapes for cogs and bearings in machines, for example.
Kevlar: Kevlar is a very strong material - about five times as strong as steel, weight for weight.
0コメント