Application research of 1-Bromooctadecane

Introduction

1-Bromooctadecane (Figure 1) has a molecular formula of C₁₈H₃₇Br and a molecular weight of 333.40. It is white crystal with a melting point of about 28.5 ℃. It is insoluble in water and soluble in organic solvents such as toluene. It is mainly used in the production of surfactants and pharmaceutical intermediates. This paper mainly introduces its related application research.

Nanocomposite hydrogels design

Highly stretchable, repairable, and tough nanocomposite hydrogels are designed by incorporating hydrophobic carbon chains to create first-layer cross-linking among the polymer matrix and monomer-modified polymerizable yet hydrophobic nanofillers to create second-layer strong polymer-nanofiller clusters involving mostly covalent bonds and electrostatic interactions. The hydrogels are synthesized from three main components: hydrophobic monomer DMAPMA-C18 by reacting N-[3-(dimethylamino)propyl]methacrylamide] (DMAPMA) with 1-bromooctadecane, monomer N,N-dimethylacrylamide (DMAc), and monomer-modified polymerizable hydrophobized cellulose nanocrystal(CNC-G) obtained by reacting CNC with 3-trimethoxysily propyl methacrylate. The polymerization of DMAPMA-C18 and DMAc and physical cross-linking due to the hydrophobic interactions between C18 chains make DMAPMA-C18/DMAc hydrogel. The additional introduction of CNC-G brings more interactions into the final hydrogel (DMAPMA-C18/DMAc/CNC-G): the covalent bonds between CNC-G and DMAPMA-C18/DMAc, hydrophobic interactions, electrostatic interactions between negatively charged CNC-G and positively charged DMAPMA-C18, and hydrogen bonds. The optimum DMAPMA-C18/DMAc/CNC-G hydrogel exhibits excellent mechanical performance with elongation stress of 1085±14kPa, strain of 4106±311%, toughness of 3.35×10⁴kJ/m³ , Young's modulus of 844 kPa, and compression stress of 5.18 MPa at 85% strain. Besides, the hydrogel exhibits good repairability and promising adhesive ability (83-260 kN/m² toward various surfaces).[1]

Functionalized silica spheres Preparation

One-pot synthesis of surface-confined ionic liquid functionalized silica spheres was proposed using N-(3-aminopropyl)imidazole, γ-isopropyltriethoxysilane and 1-bromooctadecane as starting materials. The surface modification of the silica spheres was successful with a high surface density of octadecylimidazolium, enabling the utilization of this new urea-functionalized ionic liquid-grafted silica material as stationary phase for high-performance liquid chromatography in reversed-phase mode. The long aliphatic chain combined with the multiple polar group embedded in the ligands imparted the new stationary phase fine selectivity towards PAH isomers and polar aromatics and higher affinity for phenolic compounds. The unique features of the new material, especially the effect of the urea group on the retention were elucidated by mathematic modeling.[2]

Poly(octadecylpyridinium)-grafted silica Preparation

The amphiphilic polymer-grafted silica was newly prepared as a stationary phase in high-performance liquid chromatography. Poly(4-vinylpyridine) with a trimethoxysilyl group at one end was grafted onto porous silica particles and the pyridyl side chains were quaternized with 1-bromooctadecane. The obtained poly(octadecylpyridinium)-grafted silica was characterized by elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy and Brunauer-Emmett-Teller analysis. The degree of quaternization of the pyridyl groups on the obtained stationary phase was estimated to be 70%. The selective retention behaviors of polycyclic aromatic hydrocarbons including some positional isomers were investigated using poly(octadecylpyridinium)-grafted silica as an amphiphilic polymer stationary phase in high-performance liquid chromatography and results were compared with commercially available polymeric octadecylated silica and phenyl-bonded silica columns. The results indicate that the selectivity toward polycyclic aromatic hydrocarbons exhibited by the amphiphilic polymer stationary phase is higher than the corresponding selectivity exhibited by a conventional phenyl-bonded silica column. However, compared with the polymeric octadecylated silica phase, the new stationary phase presents similar retention behavior for polycyclic aromatic hydrocarbons but different retention behavior particularly for positional isomers of disubstituted benzenes as the aggregation structure of amphiphilic polymers on the surface of silica substrate has been altered during mobile phase variation.[3]

A cysteine-functionalized zwitterionic stationary phase Preparation

In this paper, a cysteine-functionalized zwitterionic stationary phase (Cys-silica) was prepared based on the "thiol-ene" click chemistry between cysteine and vinyl-functionalized silica, and was further modified with bromoethane, 1-bromooctane and 1-bromooctadecane, respectively, to obtain a series of quaternary ammoniation-functionalized stationary phases (Cys-silica-C n, n = 2, 8 and 18). These zwitterionic stationary phases were regarded as reversed-phase/ion-exchange (RP/IEC) mixed-mode chromatography (MMC) stationary phases for protein separation. The retention behaviors of proteins on these zwitterionic stationary phases were carefully investigated. The results indicated that the retentions of acidic and basic proteins on these zwitterinonic stationary phases were significantly influenced by the acetonitrile and salt concentrations, pH of mobile phase as well as the hydrophobicity of the ligand. The separation selectivity of proteins on these zwitterionic stationary phases strongly depended on the pH value of mobile phase. The baseline separation of 6 kinds of basic proteins can be achieved at pH 8.0 using Cys-silica-C2 or Cys-silica-C8 column, and 5 kinds of acidic proteins can also be separated completely at pH 4.0 with Cys-silica-C2 column. Moreover, owing to the quaternary ammoniation-functionalization on Cys-silica by using appropriately hydrophobic bromoalkanes, the selectivity and separation efficiency of proteins can be enhanced greatly. As a result, the acidic and basic proteins can be separated completely step by step from the complex sample by adjusting pH of mobile phase using a single Cys-silica-C2 column, which illustrates that the cysteine-functionalized zwitterionic stationary phase has a great potential for protein separation.[4] 

References

1. Chen N, He X, Lu Q. Highly Stretchable, Repairable, and Tough Nanocomposite Hydrogel Physically Cross-linked by Hydrophobic Interactions and Reinforced by Surface-Grafted Hydrophobized Cellulose Nanocrystals. Macromol Rapid Commun. 2023;44(10):e2300053. doi:10.1002/marc.202300053

2. Zhang M, Tan T, Li Z, Gu T, Chen J, Qiu H. A novel urea-functionalized surface-confined octadecylimidazolium ionic liquid silica stationary phase for reversed-phase liquid chromatography. J Chromatogr A. 2014;1365:148-155. doi:10.1016/j.chroma.2014.09.018

3. Shahruzzaman M, Takafuji M, Ihara H. Porous silica particles grafted with an amphiphilic side-chain polymer as a stationary phase in reversed-phase high-performance liquid chromatography. J Sep Sci. 2015;38(14):2403-2413. doi:10.1002/jssc.201500189

4. Wang J, Wang J, Ning X, et al. pH-dependent selective separation of acidic and basic proteins using quaternary ammoniation functionalized cysteine-zwitterionic stationary phase with RPLC/IEC mixed-mode chromatography. Talanta. 2021;225:122084. doi:10.1016/j.talanta.2021.122084