US 12,435,041 B2
Process for the recovery of epsilon-caprolactam from nylon 6 comprising fishing nets
Jasper Verduyckt, Urmond (NL); Marijke Hilde Leen Groothaert, Urmond (NL); Niek Van Heijningen, Urmond (NL); Jarno Martijn Westerhof, Urmond (NL); Peter Roos, Urmond (NL); Kate Emily Murphy, Urmond (NL); and Johan Thomas Tinge, Urmond (NL)
Assigned to CAP III B. V., Urmond (NL)
Appl. No. 18/832,315
Filed by CAP III B.V., Urmond (NL)
PCT Filed Jan. 27, 2023, PCT No. PCT/EP2023/052071
§ 371(c)(1), (2) Date Jul. 23, 2024,
PCT Pub. No. WO2023/144339, PCT Pub. Date Aug. 3, 2023.
Claims priority of application No. 22154099 (EP), filed on Jan. 28, 2022; and application No. 22208660 (EP), filed on Nov. 21, 2022.
Prior Publication US 2025/0002459 A1, Jan. 2, 2025
Int. Cl. C07D 201/12 (2006.01); C07D 201/16 (2006.01); C07D 223/10 (2006.01); C08J 11/12 (2006.01); C08J 11/14 (2006.01); C08J 11/16 (2006.01)
CPC C07D 223/10 (2013.01) 17 Claims
 
1. A process for recovering purified epsilon-caprolactam from material that is selected from the group consisting of material derived from nylon 6 comprising fishing nets in a plant, wherein the plant comprises
a depolymerization section [B],
a recovery section [C], and
a purification section [D],
and wherein the process comprises the steps of:
a) charging material derived from nylon 6 comprising fishing nets to the depolymerization section [B];
b) depolymerizing the material derived from nylon 6 comprising fishing net material in the depolymerization section [B] at a temperature ranging from 180° C. to 400° C. so that an epsilon-caprolactam comprising stream is obtained;
c) discharging the epsilon-caprolactam comprising stream from the depolymerization section [B] and recovering crude epsilon-caprolactam from said stream in the recovery section [C]; and
d) purifying said crude epsilon-caprolactam in the purification section [D] to obtain purified epsilon-caprolactam wherein the purification comprises the steps of
(i) extracting the crude epsilon-caprolactam with an organic solvent, whereby an organic phase is obtained, and wherein the organic phase comprises the organic solvent, epsilon-caprolactam and impurities; and either
(ii) a) solvent switching based on back-extraction with water, or
(ii) b) solvent switching based on solvent swap distillation;
(iii) distillative removal of impurities with lower- or higher-boiling points than epsilon-caprolactam under vacuum conditions; and
(iv) obtaining purified epsilon-caprolactam by crystallization of epsilon-caprolactam from a solution comprising epsilon-caprolactam and impurities at a temperature of 10 to 95° C.