Preparation of nylon

Various methods for the preparation of nylon-3 are reported in references and patents. Among the methods, the hydrogen transfer polymerization of acrylamide is very interesting from both the academic and industrial viewpoints. 

Breslow et al.[l] found that when acrylamide was polymerized in the presence of a strong base catalyst, the polymerization occurred with hydrogen transfer, and nylon-3 was obtained. 

The polymerization was completed in the presence of a strong base catalyst (e.g. t-BuONa, t-BuOK) using inactive solvents such as toluene, pyridine, chlorobenzene and o-dichlorobenzene from 80 to 200 t. 

The initiation and propagation reactions seem to be effected by polymerization conditions such as the type of catalyst and type of solvent, but there are many unclear points [10,11]. 

In the base catalyzed polymerization of acrylamide, the vinyl polymerization is reported by Nakayama et al. [7] to occur in addition to the hydrogen transfer polymerization process. 

Purpose To demonstrate step-growth polymerization by the synthesis of Nylon-6.10. 

If Pasteur pipets are used instead of syringes to measure the reactants, use a rubber bulb to draw up the liquid. 

Do not handle the polymer rope with your bare hands more than is necessary until it has been washed free of solvent and reagents. Use latex gloves, tongs, or forceps to manipulate it. If you touch the crude polymer, immediately wash your hands with soap and warm water. 

If you use formic acid to form a film, do not let it get on your skin, because it causes deep skin burns that are not immediately obvious. If the acid does accidentally come in contact with your skin, wash the affected area immediately with 5% sodium bicarbonate solution and then with copious amounts of water. 

Preparation Sign in at www.cengage.com/login to answer Pre-Lab Exercises. 

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C, b.p. 81"C. Manufactured by the reduction of benzene with hydrogen in the presence of a nickel catalyst and recovered from natural gase.s. It is inflammable. Used as an intermediate in the preparation of nylon [6] and [66] via caprolactam and as a solvent for oils, fats and waxes, and also as a paint remover. For stereochemistry of cyclohexane see conformation. U.S. production 1980 1 megatonne. 

The preparation of nylon resins from lactam precursors involves ring opening, which is facihtated by a controlled amount of water in the reaction mixture. The salt complex condenses internally to produce the polyamide (57). The synthesis of nylon-6 [25038-54-4] from S-caprolactam is as follows ... 

An example of the first route is given in the preparation of nylon 66, which is made by reaction of hexamethylenediamine with adipie acid. The first 6 indicates the number of carbon atoms in the diamine and the second the number of carbon atoms in the acid. Thus, as a further example, nylon 6.10 is made by reacting hexamethylenediamine with sebacic acid (HOOC (CH2)s"COOH). (In this context the numbers 10,11 and 12 are considered as single numbers the need to use two digits results simply from the limitations of the decimal system.)... 

Uses Its largest uses are for polymeriztion to polybutadiene and copolymerization with styrene to make synthetic rubber (SBR) for tires and other rubber uses. Other uses include the preparation of chloroprene for oil-resistant rubber (neoprene) and hexamethylenediamine for the preparation of nylon. 

Perhaps the most interesting finding of our synthetic studies was that the interfacial preparation of poly(iminocarbonates) is possible in spite of the pronounced hydrolytic instability of the cyanate moiety (see Illustrative Procedure 3). Hydrolysis of the chemically reactive monomer is usually a highly undesirable side reaction during interfacial polymerizations. During the preparation of nylons, for example, the hydrolysis of the acid chloride component to an inert carboxylic acid represents a wasteful loss. 

C04-0063. One starting material for the preparation of nylon is adipic acid. Adipic acid is produced from the oxidation of cyclohexane ... 

Predicting Amino acids are the monomeric units that make up proteins. The reaction that joins amino acids is similar to the reaction used in the preparation of nylon. Two amino acids are shown below. Predict the structure of the molecule that will form when these two amino acids are joined. 

Additional developments in polyamide synthesis involve the preparation of nylon-1 by the anionic polymerization of alkylisocyanates at temperatures below -20°C [21]. 

The reaction is very important because cyclohexane is used widely as a solvent and also is oxidized to cyclohexanone, an important intermediate in the synthesis of hexanedioic (adipic) and azacycloheptan-2-one (caprolactam), which are used in the preparation of nylon (Section 24-3C). 

What compound did neutralize the evolving HC1 in the preparation of nylon In what part of the reaction was this supplied ... 

Prelab Exercise In the preparation of nylon by interfacial polymerization sebacoyl chloride is synthesized from decanedioic acid and thionyl chloride. What volume of hydrogen chloride is produced in this reaction What volume of sulfur dioxide is produced ... 

In the experiments that follow, you will find that the preparation of nylon by interfacial polymerization is a spectacular and reliable experiment easily carried out in one afternoon. The synthesis of Bakelite works well it requires overnight heating in an oven to complete the polymerization. Nylon by ring-opening polymerization requires skill and care because of the high temperatures involved. The polymerization of styrene also requires care, but is somewhat easier to carry out. 

For nylon-6,10 the smallest cyclooligomer contains 18 atoms in a ring. However, for nylons prepared from amino-acids, much smaller rings are possible. Nylon-6 at 270°C contains about 8 wt. % of caprolactam, the cyclic monomer [81]. Nylon-4 degrades thermally to form the very stable cyclic monomer, pyrrolidone, and the attempted preparation of nylon-4 at conventional high temperatures produces very little polymer [86]. 

The preparation of nylon in this way requires high temperature, special pressure and vacuum equipment, and a lengthy reaction period. The use of such processes is limited almost wholly to the preparation of polymers which are fusible and thermally stable. 

Figure 8.32 Process for the preparation of nylon 6.10 microcapsules by interfacial polymerisation the hexamethylenediamine in the aqueous phase reacts with the sebacoyl chloride in the nonpolar phase to form on interfociol polyamide film.

So far, the industrial application of these catalytic processes seems to be limited to the production of 1,5-cyclooctadiene (COD) (Ni catalyst preparation of flame retardants and polyoctenamers), tran5-l,4-hexadiene (Ni catalyst) and 1,5,9-cy-clododecatriene (CDT) (Ti catalyst used in preparation of nylon 12 and Vesta-mid ) (Hills Scheme 3). Recent developments are in the preparation of styrene... 

Production of this petrochemical is dedicated to a single end use, the preparation of nylon 6,6. 

For the preparation of nylon 6,6 resin, exact stoichiometry is assured by the initial preparation of the 1 1 salt, and purification of this before polymerization (Eq. 21.9). 

Batch and continuous processes are also used for the preparation of nylon 6 resin. To initiate the process, caprolactam and water are heated together at about 250°C for a period of 10-12 hr in an inert atmosphere. The ring-opened caprolactam product, 6-aminohexanoic acid (Eq. 21.11),... 

The preparation of nylon-6,6 fabric containing N-chlorinated hydantoin functional groups which were covalently linked to the surface of the polyamide was outlined. The N-chlorinated hydantoin functional groups had biocidal activity against pathogenic microorganisms. Attenuated total reflectance FTIR spectroscopy studied showed that chlorination of the treated nylon-6,6 caused a blue shift of the hydantoin amide bands. This could be used as a quality control method to measure the degree of chlorination of the nylon-6,6 and hence, of the biocidal efficiency of the material. 25 refs. 

Adipic acid for the preparation of nylon is made starting with benzene. It can be made from glucose via catechol, as shown by Frost and co-workers (see Chap. 9). It can also be made by the oxidation of petroselenic acid with ozone (12.1), the companion product lauric acid also being valuable.34... 

Explain why a continuous stirred tank reactor (CSTR) is not normally used in industry in the production of nylon 6,6. What modification is needed to make (CSTR) suitable for the preparation of nylon 6,6 ... 

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