The Chemistry of Maleimide and Its Derivatives. II. Maleimide and N-Methylolmaleimide

Abstract

15diimide in 40 ml. of dichloromethane was added dropwise over a 3O-min. period. The resetion mixture was stirred at room temperature for 24 hr., followed by removal of the precipitated N,N'dicyclohexylm by filtration. The filtrate was concentmted by dietillation and the residue was dissolved in benzene, and p d through a column ( 1 ' X 1 0 ' ) of Florisil in benzene. The product, yelloworange crystals, m.p. 37-40', weighed 39 g. (100%) and exhibited a carbonyl absorption at 1790 em.-' in the infrared spectrum of a melted film. A d . Calcd. for CIIH&N: C, 70.58; H, 4.85; N, 7.48. Found: C, 70.85; H, 5.02; N, 7.54. N-(o-Chlozsphenyl)iso"ide. To a slurry of 45 g. (0.2 mole) of N-(o-chlorophenyl)"ic acid in 1 1. of dichlore methane, a solution of 41.2 g. (0.2 mole) of N,N'-dicycl+ hexylearbodiimide in 40 ml. of dichloromethane was added dropwise over a Sin. period. The mixture was stirred at room temperature for 24 hr., followed by filtration of the N,N'-dicyclohexylurea and distillation of the solvent under reduced pressure. The residue in benzene was passed through a column of Florid and the eluates were concentrated to yield 40 g. (97%) of yellow cry&&, m.p. 60-66". Recrystdlization of a sample from 1:1 benzenepetroleum ether @.p. 39-54') gave an analytical sample, m.p 65-67'. A d . Calcd. for CloH&tNCl: C, 57.85; H, 2.91; N, 6.75. Found: C, 58.35; H, 2.73; N, 6.58. The infrared spectrum of a liquid f i l m showed strong carbonyl absorption at 1800 an.-' I 8 -h of N-n-lnbtyliaomaleimide to N-n-hiyl-"ide. A solution of 5.0 g. (0.033 mole) of N-n-butylisomaleimide, 6.06 g. (0.06 mole) of triethylamine, and 3.6 g. (0.06 mole) of acetic acid in 100 ml. of benzene was heated a t reflux for 90 min. The solution was cooled, washed with water, dilute d u m hydroxide solution, and again with water. The bemene was removed under reduced pres-sure and the midue was distilled to yield a clear liquid, b.p. 50-55" (0.5 mm.). Vapor phase chromatographic analysis of this material showed it to be a mixture containing 40% N-n-butylisomaleimide, 59.4% N-n-butylmaleimide and 0.6% of an unknown impurity. The recovery Isomerization of N-phen&aom&imide to N -p h e n y l d eimide. A mixture of 5.0 g. (0.029 mole) of N-phenylisomaleimide, 1.0 g. (0.012 mole) of anhydrous d u m acetate and 15 ml. of acetic anhydride was heated on the steam bath for 1 hr. After the mixture had cooled to 2 5 O , it was poured into 100 ml. of water causing long, yellow needles to separate. These were collected and dried, 4.5 g. (90%) m.p. 90-91'. A mixture melting point with an authentic sample of N-phenylmaleimide was undepressed. When d u m acetate was absent in this reaction, the starting material was recovered.

Synthesis and characterization of modified bismaleimide/polysulfone semi‐interpenetrating polymer networks

“…This might be due to different polymerization mechanism as it was reported that purple or red color indicates the anionic polymerization of BMI. 25 Absence of purple color in the case of i-PrOH might indicate that BMI probably underwent a free radical polymerization as shown in Scheme 2 and reported elsewhere. 28 However, anionic polymerization of BMI using EtOH was reported in this work whereas complete study with i-PrOH would be reported later.…”

“…The red color indicates an anionic polymerization of BMI, which leads to a low-molecular-weight polymer compared to that from a radical polymerization as dis-cussed elsewhere. 25 On the basis of pulse radiolysis and electron spin resonance studies, 26,27 this BMI polymerization might be also described as shown in Scheme 1. The time required for these changes and the rate of polymerization depend on the concentration of ingredients, viscosity, mixing rate, and conditions such as pressure, temperature, and energy ray.…”

Formation and thermal stability of BMI-based interpenetrating polymers for gas separation membranes

“…However, an increase in the brightness of yellow color was obtained. This may indicate that polymerization mechanism is different because it is known that purple or red color is obtained upon anionic polymerization of BMI that usually leads to a lower molecular weight polymer [23]. Absence of red or purple color in the case of isopropanol indicates that BMI probably underwent a free radical polymerization as reported elsewhere [24].…”

Performance of PEI/BMI semi-IPN membranes for separations of various binary gaseous mixtures☆

“…Appearance of dark red color was an indication for complete polymerization of BMI to a low molecular weight resin and mixing for longer time did not lead to a significant change in the solution. This was due to anionic polymerization of BMI that usually led to a low molecular weight polymer as discussed elsewhere [14]. All polymer solutions were suitable for producing gas separation membranes as long as there is no large phase separation or precipitation.…”

“…The progress of polymerization was followed by measuring the viscosity, color change and spectroscopic analysis as discussed in details in our earlier work [11]. It is worth noting that in situ anionic polymerization of BMI has many advantages such as avoiding the addition of complicated initiators or catalysts as well as obtaining low molecular weight thermosetting polymer as discussed elsewhere [14]. Using EtOH as a proton donor, the color of the PEI-BMI polymeric solution underwent gradual change from light yellow to bright crimson.…”