1-Pentadecanol is generally a stable compound. Like other long-chain primary alcohols, 1-pentadecanol exhibits low oral, skin and respiratory toxicity.[3] However, it may be slightly to moderately irritating to the eyes and skin, and prolonged contact with undiluted alcohols can lead to defatting of the skin.[3] Accordingly, Royal Dutch Shell recommends that eye protection, chemical-resistant gloves, and other protective clothing be worn when handling large amounts of 1-pentadecanol.[7] It floats on water, and can catch fire under certain conditions; in the case of a fire, carbon dioxide, foam, sand, earth, or dry chemical type fire extinguishers are recommended.[7]
When cooling from a liquid state, 1-pentadecanol (at 316.3K, at standard pressure) assumes a crystalline structure known as the α-form, a "rotator phase" in which molecules can rotate about their long axes. While other long-chain alcohols, cooling further from the α-form, experience a solid-state transition into either a γ-form (with chains tilted to the basal plane normal) or a β-form (with vertical chains), 1-pentadecanol has been observed to exclusively assume the β-form when cooling, which it does at 311.5K. Differential thermal analysis measurements on 1-pentadecanol were performed at temperatures from 300 to 370K and pressures of up to 250MPa; on heating, it was observed to change from a crystalline phase (β-form) to a rotator phase (α-form) a few degrees below its melting point.[9] The observation of this rotator state in pentadecanol was substantiated by dielectric measurements that confirmed its orientational disorder. No triple point exists for 1-pentadecanol.[9]
Production
The Shell corporation uses a proprietary process for the synthesis of 1-pentadecanol (referring to it by the trade name Neodol 5) via hydroformylation of olefins produced from ethylene.[6]
Fungal oxidization and assimilation of pentadecane has been observed by two citric acid-producing Candida strains (wild type KSH 21 and mutant 337), transforming it into both pentadecanol and pentadecanoic acid through oxidization at one of the terminal carbon atoms.[12] The highest conversion to pentadecanol seen in the 1977 study was from a 3-day fermenter culture of the 337 strain, in which 85.5mg was developed per 10g of pentadecane. Some conversion to 2-pentadecanol and 2-pentadecanone was also observed.[12]
Applications
In a 1981 paper, the activities of various primary alcohols were evaluated as substrates for alkyl DHAP synthase's catalysis of fatty alcohol with acyl dihydroxyacetone phosphate in Erlich ascites tumor cells. The specificity of the cells' microsomal alkyl DHAP synthase with respect to different alcohols was investigated; pentadecanol had an activity of approximately 0.2mol/min/mg protein.[13]
In a 1995 paper by the same research group, the 0.78μg/mL MIC against P.acnes was replicated, and remained the lowest MIC against P.acnes among all primary alcohols tested (from C6 to C20). 1-Pentadecanol was, additionally, found to have a MIC of 6.25μg/mL against Brevibacterium ammoniagenes, and a MIC greater than 800μg/mL (essentially, no effect) against the dermatomycotic yeast Pityrosporum ovale. It, along with 1-hexadecanol, was found to be selectively antimicrobial against P. acnes and not other Gram-positive bacteria (unlike other alcohols, like 1-dodecanol, that were more broadly antimicrobial to all Gram-positive bacteria).[15]
A 2018 computational chemistry study investigated possible uses of alcohol compounds as mycobactericidal disinfectants for the control of Mycobacterium tuberculosis. The study computationally evaluated Gibbs free energy (∆G) for the molecular docking of alcohols C1 (methanol) to C15 (pentadecanol) as ligands of the InhA, MabA, and PanK receptors. The observed trend was that binding energy between ligand and receptor increased with chain length; pentadecanol, the longest alcohol tested, had a ∆G computationally estimated as −4.9kcal/mol with InhA, −4.9kcal/mol with MabA, and −5.5kcal/mol with PanK. This was compared with triclosan (whose ∆G for those bindings is −6.4kcal/mol, −6.7kcal/mol and −7.0kcal/mol respectively); pentadecanol was found to have "potency" as a mycobactericidal agent and suggested as a "reference" for further development of receptor-targeted mycobactericidal agents.[16]
The properties of fluorinated 1-pentadecanols have been investigated as potential amphiphilic species for aiding adsorption of the pulmonary surfactantdipalmitoylphosphatidylcholine (DPPC). DPPC, while contributing to film rigidity on the surface of alveoli, has poor adsorption and respreading qualities; highly fluorinated amphiphiles can compatibilize it to other surfaces, but at the cost of bioaccumulation both in the human body and in the environment. Therefore, the interaction of several partially fluorinated 1-pentadecanols with DPPC in a Langmuir monolayer was analyzed in a 2018 paper. The molecules were F4H11OH, F6H9OH, and F8H7OH; as the fluorination degree increased, so did hydrophobicity.[17]
^Sigma Aldrich. "MSDS - 412228". Archived from the original on 2020-09-01. Retrieved 2019-08-23.
^ abVenkatesan, K.; Srinivasan, K. V. (2008), "A novel stereoselective synthesis of pachastrissamine (jaspine B) starting from 1-pentadecanol", Tetrahedron: Asymmetry, 19 (2): 209–215, doi:10.1016/j.tetasy.2007.12.001
^Artal, Manuela; Pauchon, Veronique; Embid, José Muñoz; Jose, Jacques (1998), "Solubilities of 1-Nonanol, 1-Undecanol, 1-Tridecanol, and 1-Pentadecanol in Supercritical Carbon Dioxide at T = 323.15 K", Journal of Chemical & Engineering Data, 43 (6), American Chemical Society: 983–985, doi:10.1021/je980117r
^ abReuter, Jörg; Würflinger, Albert (October 1995). "Differential Thermal Analysis of Long-Chain n-Alcohols under High Pressure". Berichte der Bunsengesellschaft für physikalische Chemie. 99 (10): 1247–1251. doi:10.1002/bbpc.199500067.
^Barik, Anandamay; Azmi, Syed; Karmakar, Amarnath; Soumendranath, Chatterje (2018), "Antibacterial Activity of Long-Chain Primary Alcohols from 'Solena amplexicaulis' Leaves", Proceedings of the Zoological Society, 71 (4), Springer India: 313–319, doi:10.1007/s12595-017-0208-0, S2CID14862566
^ abSouw, P.; Luftmann, H.; Rehm, H. J. (1977). "Oxidation of n-alkanes by citric acid producing Candida spp". European Journal of Applied Microbiology and Biotechnology. 3 (4): 289–301. doi:10.1007/BF01263329. S2CID43536146.