Dioctan-2-yl methylphosphonate
[CAS# 76341-63-4]

Identification

• Classification: Chemical reagent >> Organic reagent >> Phosphonate / phosphonate
• Name: Dioctan-2-yl methylphosphonate
• Synonyms: 2-[methyl(octan-2-yloxy)phosphoryl]oxyoctane
• Molecular Formula: C₁₇H₃₇O₃P
• Molecular Weight: 320.45
• CAS Registry Number: 76341-63-4
• SMILES: CCCCCCC(C)OP(=O)(C)OC(C)CCCCCC

Properties

• Density: 0.9±0.1 g/cm³ Calc.^*
• Boiling point: 386.5±11.0 ºC 760 mmHg (Calc.)^*
• Flash point: 201.1±39.6 ºC (Calc.)^*
• Index of refraction: 1.438 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Discovory and Applicatios

Dioctan-2-yl methylphosphonate belongs to the broader family of dialkyl methylphosphonates, a group whose chemistry has been mapped through decades of work on phosphorus–carbon and phosphorus–oxygen bond construction. Early studies established that alkyl phosphonates could be accessed reliably through alcohol–phosphonic dichloride esterification, a route that tolerates substantial steric bulk and branching in the alcohol component. These findings made long-chain and secondary-alcohol derivatives synthetically accessible.

Explorations into the physical behavior of long-chain phosphonates revealed their characteristic high hydrophobicity, low volatility, and stability toward hydrolysis relative to shorter-chain congeners. This behavior arises from suppression of intermolecular hydrogen bonding and the damping effect of the long aliphatic substituents on the polar P=O fragment. Such derivatives were later assessed as components in plasticizer development, surface-modifying agents, and boundary-lubrication additives due to their amphiphilic but strongly lipophilic character.

Mechanistic investigations into P–O ester formation and hydrolysis provided foundational understanding of how steric and electronic effects modulate phosphorus reactivity. Secondary alcohol–derived phosphonates, analogous to the octan-2-yl group, were shown to undergo ester cleavage more slowly than their primary counterparts, a trend attributed to increased steric shielding around the phosphorus center and altered solvation dynamics.

Further work on dialkyl methylphosphonates focused on their utility as intermediates in Michaelis–Arbuzov transformations and phosphorylation chemistry. Their stability makes them suitable precursors or inert carriers in multistep sequences requiring controlled reactivity of the phosphorus atom. Studies on thermal decomposition and oxidative stability added insight into the behavior of long-chain phosphonates under processing conditions relevant to materials applications.

Collectively, the literature surrounding alkyl phosphonates—while seldom naming dioctan-2-yl methylphosphonate specifically—establishes reliable, experimentally validated principles governing the synthesis, structure, and stability of molecules within this class. The compound fits well within these patterns, behaving as a lipophilic dialkyl phosphorus ester with predictable reactivity derived from its methylphosphonate core and bulky secondary-alkyl substituents.

References

2022. Extraction of neptunium(VI) from nitric acid solution with di(1-methyl-heptyl) methyl phosphonate. Journal of Radioanalytical and Nuclear Chemistry, 331(3).
DOI: 10.1007/s10967-021-08130-y

1997. Separation of Zirconium(IV) and Hafnium(IV) by Extraction Chromatography Using Di(l-methylheptyl) Methylphosphonate as a Stationary Phase. Analytical Sciences, 13(Suppl).
DOI: 10.2116/analsci.13.27