Acylated caprolactam

Polyamide-6 (nylon-6) can form block copolymers with rubber and with poly(dimethylsilox-ane)." In the latter case, the polysiloxane forms first by living polymerization and is terminated by an acylated caprolactam. The caprolactam portion of the molecule is then polymerized with the aid of lithium caprolactamate ... 

U.S. 5405412 (1995) NV A. D. Willey et al., N-acyl caprolactam, NOBS multistained fabrics Effective bleach system... 

Typical Procedure for the Preparation of Polyimides Containing Pendant N-Acylated Caprolactam Moieties. After BAPBC (1.5(XX) g, 3.4772 mmol) was polymerized with 33 4,4 -biphenyltetracarboxylic dianhydride (BPDA) (1.0229 g, 3.4772 mmol) in N-methyl-2-pyirolidinone (NMP) (14.5 ml) at 22 C for 12 h, pyridine (0.633 g, 8.(X) mmol) and acetic anhydride (0.816 g, 8.00 mmol) were added. After stirring for another 24 h at 22°C under N2, the solution was dilut with NMP and slowly added to vigorously stirred ethanol. The polymer that precipitated was... 

Typical Procedure for the Preparation of Polyimides End-Capped with N-Acylated Caprolactam Moieties. After a mixture of o-tolidine (OTOL) (2.1231 g, 10.000 mmol), BPDA (0.9120 g, 3.100 mmol), 2,2 -bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydryde (6FT)A) (3.2870 g, 7.400 mmol) and NMP (35.83 g, 15 wt% solid) was stirred at 22 under N2 for 10 h, 4-aminobenzoylcaprolactam (0.2322 g, 1.000 mmol) was added, and the reaction mixture was stirred for another 10 h. Pyridine (1.7600 g) and acetic anhydride (2.2440 g) were added, and the reaction mixture was stirr for an additional 24 h. The solution was diluted with NMP and poured into ethanol. The end-capped polyimide (OTOL/BPDA/6FDA, 100/30/70 molar ratio, Mn= 12,000) that precipitated was collected by filtration, washed with methanol and dried at room temperature under reduced pressure. 

Multi-functionalized Polyimides. As shown in Scheme 3, the polyimides containing pendant N-acylated caprolactam moieties were prepared by the two-step polycondensation of BAPBC with commercial dianhydrides. A polyamic acid (PAA) viscous solution was formed by stirring equimolar amounts of the derivatized diamine with the dianhydride in NMP at room temperature. The subsequent chemical imidization was carried out by adding pyridine and acetic anhydride to the PAA solution to produce the multi-functional polyimide. The amount of pendant groups incorporated and the rigidity of the polyimide chains were varied by copolymerizations with non-derivatized diamines such as o-tolidine (OTOL), m-tolidine (MTOL), or 2,2 -bis(trifluoro methyl)benzidine (PFMB). The incorporation of the N-acylated caprolactam moieties in the polyimide chains was confirmed by the FTIR absorptions at 2931 and 2864 cm (Uas and CH2 in pendant acylated caprolactam moieties) as well as the absorptions at 1778 and 1727 cm (v s and Vg, C=0 in imide ring). 

Difunctionalized Polyimides. As shown in Scheme 4, N-acylated caprolactam end-capped polyimides were prepared by the two-step polycondensation of a diamine, excess dianhydride and 4-aminobenzoylcaprolactam. The diamine was first treated with an excess amount of dianhydride at room temperature in NMP to produce an anhydride-terminated polyamic acid. This oligomer was allowed to react with the end-capping agent 4-aminobenzoylcaprolactam to form an N-acylated caprolactam end-capp polyamic acid, which was then converted to the corresponding polyimide with pyridine and acetic anhydride. The molecular weight of the end-capped polyimide was controlled by varying the molar ratio of the diamine to dianhydride. 

The reaction of caprolactam with the polymeric activators was followed with FTIR spectroscopy. The incorporation of N-acylated caprolactam moieties in the polyimide chains was first confirmed by the appearance of the characteristic acylated caprolactam bands near 2931 and 2864 cm-. The polymer also displayed characteristic imide carbonyl absorptions at 1778 and 1727 cm-i. As the graft or block copolymerizations proceeded, the intensities of the bands characteristic of nylon 6 segments at 3300,3085,1642 and 1545 cm- increased dramatically. 

Enzymatic hydrolysis is also used for the preparation of L-amino acids. Racemic D- and L-amino acids and their acyl-derivatives obtained chemically can be resolved enzymatically to yield their natural L-forms. Aminoacylases such as that from Pispergillus OTj e specifically hydrolyze L-enantiomers of acyl-DL-amino acids. The resulting L-amino acid can be separated readily from the unchanged acyl-D form which is racemized and subjected to further hydrolysis. Several L-amino acids, eg, methionine [63-68-3], phenylalanine [63-91-2], tryptophan [73-22-3], and valine [72-18-4] have been manufactured by this process in Japan and production costs have been reduced by 40% through the appHcation of immobilized cell technology (75). Cyclohexane chloride, which is a by-product in nylon manufacture, is chemically converted to DL-amino-S-caprolactam [105-60-2] (23) which is resolved and/or racemized to (24)... 

Anionic polymerization of lactams was shown to proceed according to what is called the activated monomer mechanism. With bischloroformates of hydroxy-terminated poly(tetramethyleneglycol) and poly(styrene glycol) as precursors for a polymeric initiator containing N-acyl lactam ends, block copolymers with n-pyrrol-idone and e-caprolactam were obtained by bulk polymerizations in vacuum at 30 and 80 °C, respectively361. ... 

Zeolites have also been described as efficient catalysts for acylation,11 for the preparation of acetals,12 and proved to be useful for acetal hydrolysis13 or intramolecular lactonization of hydroxyalkanoic acids,14 to name a few examples of their application. A number of isomerizations and skeletal rearrangements promoted by these porous materials have also been reported. From these, we can underline two important industrial processes such as the isomerization of xylenes,2 and the Beckmann rearrangement of cyclohexanone oxime to e-caprolactam,15 which is an intermediate for polyamide manufacture. Other applications include the conversion of n-butane to isobutane,16 Fries rearrangement of phenyl esters,17 or the rearrangement of epoxides to carbonyl compounds.18... 

Chemical Composition. In polyamide 6 (PA 6, polymerization product of e-caprolactam) and polyamide 66 (PA 66, adipic acid polymerized with hexamethylene-diamine) one chain end consists of an amino group, which can be present in the free state or in the acylated form. Amino groups are of special importance for dyeing because they form ammonium groups in an acidic dyebath by addition of protons. The lower dye uptake in comparison to wool is caused by the comparatively low number of amino groups. The depth of color achieved on PA 6 is somewhat less than that on PA 66. 

A -Butylpyridinium tetrafluoroborate, containing dissolved phosphorus pentachloride, allows catalytic Beckmann rearrangement of cyclohexanone oxime giving e-caprolactam with good conversion and selectivity <2001TL403>. The same ionic liquid containing dissolved ytterbium(m) trifluoromethanesulfonate was used to perform Friedel-Crafts acylation of furan and thiophene <2005JIG398>. 

The reaction of lactim ethers with hydrazine and its derivatives proceeds readily. The resulting compounds are highly reactive and can be used in different reactions involving the side chain and the cyclic nitrogen atom.5,54,76> 80-82 For example, the treatment of caprolactam hydrazone (40) with nitrous acid results in pentamethyl-enetetrazole (41),54,80,81 and the use of diiferent lactim ethers gives other tetrazoles.32,35 The synthesis of polymethylenetetrazoles from lactim ethers and HN3,83 and also84 from HN3 and O-acyl lactims (or imidochlorides of lactams), obtained from lactams and sulfochlorides or phosphoryl chloride, may be mentioned. 

In the copolymerization of lactams of different ring size, the relative rate of incorporation of the two lactams is not necessarily determined by the reaction in which the lactam ring is cleaved. Vofsi et al. [167] showed that in the anionic copolymerization of caprolactam and pyrrolidone (Table 9), the acylation of lactam anions with the exocyclic carbonyl of the growing acyllactam structure (i.e. exchange of monomer units) occurs faster than acylation with the cyclic carbonyl (propagation), viz. 

Low-temperature polymerization of caprolactam can be accomplished by an anionic mechanism in which ring opening is effected by a strong base, usually with the addition of an acylating cocatalyst (e.g., acetic anhydride) as illustrated by Reaction 12. 

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