1-Dodecylpyridinium Chloride Monohydrate

Dodecylpyridinium chloride removal by persulfate activation using UVA radiation or temperature: experimental design and kinetic modeling

The degradation of dodecylpyridinium chloride (DPC) by SO₄^•- and HO^• radicals, generated by UVA and thermal-activated persulfate (PS) was investigated. Temperatures of 30-50°C were used for the heat activation of PS. In the case of UVA/PS, the effects of [PS]₀ and specific photon emission rate (E_P,0) were studied through a Doehlert design coupled with statistical analysis and response surface methodology. The results showed high DPC removal (99.8%) and pseudo-first-order degradation rate (k_obs = 0.0971 min^-1) for [DPC]₀ = 4.60 ± 0.11 mg L^-1, [PS]₀ = 7.75 mmol L^-1, and E_P,0 = 0.437 μmol photons L^-1 s^-1, with a major role of SO₄^•- radicals in comparison with HO^•. The specific DPC degradation rate found under these conditions was higher than that observed for thermal activation at 50°C and [PS]₀ = 5.5 mmol L^-1 (k_obs = 0.0712 min^-1) over the same time, although complete DPC removal was also achieved in the latter. The positive effect of E_P,0 on DPC degradation by the UVA/PS process depends on PS concentrations, with k_obs values increasing linearly with [PS]₀ in the range 7.75-10 mmol L^-1, whereas lower E_P,0 values can be compensated by increasing [PS]₀ up to about 10 mmol L^-1, without significant scavenging. The second-order rate constants of DPC with HO^• and SO₄^•-, estimated by comprehensive kinetic modeling, were 8.26 × 10⁹ and 4.44 × 10⁹ L mol^-1 s^-1, respectively. Furthermore, higher [DPC]₀ would negatively affect the DPC degradation rate by the UVA/PS process, while 62% DPC removal was obtained in WWTP water, which can be considered good given the complexity of the real matrix. Finally, our results shed light on the possibility of using available UVA radiation (4.5%) in solar irradiance on the Earth's surface, making this treatment process more sustainable and cost-effective.

The crystal structure of 1-dodecylpyridin-1-ium bromide monohydrate, C17H32BrNO

C17H32BrNO, triclinic, P 1 ‾ $P\bar{1}$ (no. 2), a = 5.344(3) Å, b = 7.871(5) Å, c = 23.614(15) Å, α = 95.990(12)°, β = 95.747(12)°, γ = 98.386(12)°, V = 970.5(11) Å3, Z = 2, R gt(F) = 0.0550, wR ref(F 2) = 0.1527, T = 293(2) K.

CCDC no.: 1983264

1-Tetra-decyl-pyridinium bromide monohydrate

In the title compound, C₁₉H₃₄N⁺·Br⁻·H₂O, the dihedral angle between the trans-planar alkyl side chain and the pyridinium ring is 52.73 (7)°. In the crystal structure, O—H⋯Br, C—H⋯Br and C—H⋯O hydrogen bonds form a network, while the hydro­phobic alkyl chains inter­digitate, forming bilayers.

Molecular and crystal structures of N-(beta-D-galactopyranosyl)pyridinium bromide and its per-O-acetylated derivative

1H NMR spectroscopy and X-ray diffraction data are described for N-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)pyridinium bromide and N-(beta-D-galactopyranosyl)pyridinium bromide. X-ray crystallography revealed that the O-acetylated salt crystallizes with two molecules of water and one molecule of ethanol.