following new heading: 9902.06.21 N-Butyl-2,2,6,6-tetramethylpiperidin-4-amine (CAS No. 36177–92–1) (provided for in subheading 2933.39.91) Free No change No change On or before 12/31/2020 . 515. Food and feed preservative Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.06.22 Ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) (CAS No. 91–53–2) (provided for in subheading 2933.49.10) Free No change No change On or before 12/31/2020 . 516. Quinclorac Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.06.23 3,7-Dichloro-8-quinolinecarboxylic acid (Quinclorac) (CAS No. 84087–01–4) (provided for in subheading 2933.49.30) Free No change No change On or before 12/31/2020 . 517. Cloquintocent-mexyl Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.06.24 1-Methylhexyl [(5-chloroquinolin-8-yl)oxy]acetate (Cloquintocet-mexyl) (CAS No. 99607–70–2) (provided for in subheading 2933.49.60) 4.3% No change No change On or before 12/31/2020 . 518. Cloquintocet acid Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.06.25 (5-Chloro-8-quinolyloxy)acetic acid (Cloquintocet) (CAS No. 88349–88–6) (provided for in subheading 2933.49.60) Free No change No change On or before 12/31/2020 . 519. Quinaldine Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.06.23 2-Methylquinoline (Quinaldine) (CAS No. 91–63–4) (provided for in subheading 2933.49.70) Free No change No change On or before 12/31/2020 . 520. Butafenacil Subchapter II of chapter 99 is amended by inserting in numerical sequence the following new heading: 9902.06.27 (2-Methyl-1-oxo-1-prop-2-enoxypropan-2-yl) 2-chloro-5-[3-methyl-2,6-dioxo-4-(trifluoromethyl)pyrimidin-1-yl]benzoate (Butafenacil) (CAS No. 134605–64–4) (provided for in subheading 2933.59.10) Free No change No change On or before