SUPPLEMENTARY INFORMATION:

Request To Add Substance to the List

(a) Overview.

A petition was filed pursuant to Rev. Proc. 2022-26 (2022-29 I.R.B. 90), requesting that nylon 6 be added to the list of taxable substances under section 4672(a) of the Internal Revenue Code (List). The notice of filing summarizing the nylon 6 petition and requesting comments was published in the Federal Register on February 22, 2024 (89 FR 13399)(original notice of filing). The Treasury Department and the IRS received no written comments in response to the original notice of filing and a public hearing was neither requested nor held. After the comment period for the original notice of filing closed, an error was discovered in the stoichiometric material consumption equation for nylon 6, and the petitioner subsequently provided a corrected petition.

This supplemental notice of filing provides the corrected stoichiometric material consumption equation for nylon 6 in paragraph (b) of this document. The stoichiometric material consumption equation is corrected to read as follows:

nC₆ H₆ (benzene) + nC₃ H₆ (propylene) + 2.5nO₂ (oxygen) + 0.5nCH₄ (methane) + 5nNH₃ (ammonia) + 2nH₂ O (water) + 2nSO₂ (sulfur dioxide) → (C₆ H₁₁ NO)_n (nylon 6) + nC₃ H₆ O (acetone) + 2n(NH₄)₂ SO₄ (ammonium sulfate) + 0.5n CO₂ (carbon dioxide)

The other petition information provided in paragraph (b) of this document is unchanged from the original notice of filing for nylon 6. Although the only change from the original notice of filing is to the stoichiometric material consumption equation, this document also includes all of the other information presented on the corrected petition to avoid confusion and is provided for public notice and comment pursuant to section 9 of Rev. Proc. 2022-26.

The petition requesting the addition of nylon 6 to the List is based on weight and—as noted previously—contains the information detailed in paragraph (b) of this document. The publication of petition information in this supplemental notice of filing is not a determination and does not constitute Treasury Department or IRS confirmation of the accuracy of the information published. ( printed page 66176)

Pursuant to section 10.02 of Rev. Proc. 2022-26, the IRS and Petitioner agreed to extend the 180-day determination period.

(b) Petition Content.

(1) Substance name: Nylon 6.

(2) Petitioner: AdvanSix Inc., an exporter of nylon 6.

(3) Proposed classification numbers:

(i) HTSUS number: 3908.10.00.

(ii) Schedule B number: 3908.10.0000.

(iii) CAS number: 25038-54-4.

(4) Petition filing dates:

(i) Petition filing date for purposes of making a determination: November 8, 2023.

(ii) Petition filing date for purposes of section 11.02 of Rev. Proc. 2022-26: July 1, 2022.

(5) Description from petition: According to the petition, nylon 6, or poly(caprolactam), is a semicrystalline polyamide that has broad use in textile fibers, engineering plastics, food packaging films, and monofilaments. The number “6” in nylon 6 refers to the number of carbon atoms in each polymeric repeat unit. Nylon 6 may be utilized neat or with functional additives by melt processing into the desired final form.

Nylon 6 is made from benzene, propylene, ammonia, methane, and sulfuric acid; however, sulfuric acid is cancelled from the stoichiometric material consumption equation due to no net consumption/production. Taxable chemicals constitute 46.64 percent by weight of the materials used to produce this substance.

(6) Process identified in petition as predominant method of production of substance: The predominant method of production of nylon 6 is the “hydrolytically initiated ring-opening polymerization of caprolactam” which is also referred to in industry literature as the “hydrolytic polymerization of nylon 6.” This process is termed “hydrolytic” because water plays a key role in the chemical mechanism. Nylon 6 is produced almost exclusively through this method because it is easier to control and better adapted for large-scale operations.

The hydrolytic polymerization of nylon 6 generally entails heating a mixture of caprolactam and water to ~270°C in an inert atmosphere of nitrogen and holding until equilibrium conditions are achieved. The three principal reactions in this process are summarized below:

1. In the initiation step of the process, the caprolactam ring is hydrolyzed via ring opening with the addition of one water molecule to become amino-caproic acid.

2. In the next step of the mechanism, the amino-caproic acid acts as the initiating species to begin the addition polymerization by ring-opening of caprolactam.

3. The last major mechanism step of the hydrolytic polymerization of nylon 6 is the condensation of primary amine and carboxylic acid chain-ends to form an amide linkage in the now higher molecular weight polyamide with the simultaneous loss of a water molecule.

(7) Stoichiometric material consumption equation, based on process identified as predominant method of production:

nC₆ H₆ (benzene) + nC₃ H₆ (propylene) + 2.5nO₂ (oxygen) + 0.5nCH₄ (methane) + 5nNH₃ (ammonia) + 2nH₂ O (water) + 2nSO₂ (sulfur dioxide) → (C₆ H₁₁ NO)_n (nylon 6) + nC₃ H₆ O (acetone) + 2n(NH₄)₂ SO₄ (ammonium sulfate) + 0.5n CO₂ (carbon dioxide)

(8) Tax rate calculated by Petitioner, based on Petitioner's conversion factors for taxable chemicals used in production of substance:

(i) Tax rate: $14.77 per ton.

(ii) Conversion factors: 0.69 for benzene; 0.37 for propylene; 0.75 for ammonia; 0.07 for methane.

(9) Public docket number: IRS-2024-0005.