Synthesis and Characteristics of Dodecyl Isopropylolamine and Derived Surfactants

The Formulation, Development and Application of Oil Dispersants

Oil spills in open waters pose a significant threat to marine life. The application of dispersant as an oil-spill response is a promising approach to minimize the environmental burden caused by these accidental events. Dispersants have been accepted and applied by many countries around the world as a countermeasure in responding to oil spills due to their great success and advancements in recent years. This review covers different approaches for design and development of chemical formulas of oil dispersants with the aim to improve dispersing efficiencies, followed by formulating non-chemical dispersants, which are more environmentally friendly approaches. The encouraging properties motivate scientific communities to research and develop these non-chemical-based dispersants. In general, this review intends to offer a multi-perspective overall picture of progress made in recent years to develop and apply different dispersants suitable for combating oil spills.

Crystal structure and Hirshfeld surface analysis of 5,7-diphenyl-1,2,3,5,6,7-hexa-hydro-imidazo[1,2-a]pyridine-6,6,8-tricarbo-nitrile methanol mono-solvate

In the title compound, C22H17N5·CH4O, the imidazolidine ring of the 1,2,3,5,6,7-hexa-hydro-imidazo[1,2-a]pyridine ring system is a twisted envelope, while the 1,2,3,4-tetra-hydro-pyridine ring adopts a twisted boat conformation. In the crystal, pairs of mol-ecules are linked by O-H⋯N and N-H⋯O hydrogen bonds via two methanol mol-ecules, forming a centrosymmetric R 4 4(16) ring motif. These motifs are connected to each other by C-H⋯N hydrogen bonds and form columns along the a axis. The columns form a stable mol-ecular packing, being connected to each other by van der Waals inter-actions. A Hirshfeld surface analysis indicates that the most significant contributions to the crystal packing are from H⋯H (43.8%), N⋯H/H⋯N (31.7%) and C⋯H/H⋯C (18.4%) contacts.

Crystal structure and Hirshfeld surface analysis of 4,5-di-bromo-2-(4-meth-oxy-phen-yl)-2,3,4,4a,5,6,7,7a-octa-hydro-1H-4,6-ep-oxy-1H-cyclo-penta-[c]pyridin-1-one

The mol-ecule of the title compound, C15H15Br2NO3, comprises a fused tricyclic system consisting of two five-membered rings (cyclo-pentane and tetra-hydro-furan) and one six-membered ring (tetra-hydro-pyridinone). Both five-membered rings of the tricyclic system have envelope conformations, and the conformation of the six-membered cycle is inter-mediate between chair and half-chair. In the crystal, the mol-ecules are linked by C-H⋯O hydrogen bonds and C-H⋯π, C-Br⋯π and C⋯O inter-actions into double layers. The layers are connected into a three-dimensional network by van der Waals inter-actions.

(3aS,4R,5R,6S,7aR)-4,5-Di-bromo-2-[4-(tri-fluoro-meth-yl)phen-yl]-2,3,3a,4,5,6,7,7a-octa-hydro-3a,6-ep-oxy-1H-isoindol-1-one: crystal structure and Hirshfeld surface analysis

The asymmetric unit of the title compound, C15H12Br2F3NO2, consists of two crystallographically independent mol-ecules. In both mol-ecules, the pyrrolidine and tetra-hydro-furan rings adopt an envelope conformation. In the crystal, mol-ecule pairs generate centrosymmetric rings with R 2 2(8) motifs linked by C-H⋯O hydrogen bonds. These pairs of mol-ecules form a tetra-meric supra-molecular motif, leading to mol-ecular layers parallel to the (100) plane by C-H⋯π and C-Br⋯π inter-actions. Inter-layer van der Waals and inter-halogen inter-actions stabilize mol-ecular packing. The F atoms of the CF3 groups of both mol-ecules are disordered over two sets of sites with refined site occupancies of 0.60 (3)/0.40 (3) and 0.640 (15)/0.360 (15). The most important contributions to the surface contacts of both mol-ecules are from H⋯H (23.8 and 22.4%), Br⋯H/H⋯Br (18.3 and 12.3%), O⋯H/H⋯O (14.3 and 9.7%) and F⋯H/H⋯F (10.4 and 19.1%) inter-actions, as concluded from a Hirshfeld surface analysis.

Crystal structure and Hirshfeld surface analysis of (RS)-3-hy-droxy-2-{[(3aRS,6RS,7aRS)-2-(4-methyl-phenyl-sulfon-yl)-2,3,3a,6,7,7a-hexa-hydro-3a,6-ep-oxy-1H-isoindol-6-yl]meth-yl}isoindolin-1-one

The title compound, C24H24N2O5S, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In the central ring systems of both mol-ecules, the tetra-hydro-furan rings adopt envelope conformations, the pyrrolidine rings adopt a twisted-envelope conformation and the six-membered ring is in a boat conformation. In mol-ecules A and B, the nine-membered groups attached to the central ring system are essentially planar (r.m.s. deviations of 0.002 and 0.003 Å, respectively). They form dihedral angles of 64.97 (9) and 56.06 (10)°, respectively, with the phenyl rings. In the crystal, strong inter-molecular O-H⋯O hydrogen bonds and weak inter-molecular C-H⋯O contacts link the mol-ecules, forming a three-dimensional network. In addition weak π-π stacking inter-actions [centroid-to centroid distance = 3.7124 (13) Å] between the pyrrolidine rings of the nine-membered groups of A mol-ecules are observed. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to qu-antify the inter-molecular inter-actions present in the crystal, indicating that the environments of the two mol-ecules are very similar. The most important contributions for the crystal packing are from H⋯H (55.8% for mol-ecule A and 53.5% for mol-ecule B), O⋯H/H⋯O (24.5% for mol-ecule A and 26.3% for mol-ecule B) and C⋯H/H⋯C (12.6% for mol-ecule A and 15.7% for mol-ecule B) inter-actions.

Crystal structure and Hirshfeld surface analysis of 2-benzyl-4,5-di-bromo-2,3,3a,4,5,6,7,7a-octa-hydro-3a,6-ep-oxy-1H-isoindol-1-one

The title compound, C15H15Br2NO2, crystallizes with two mol-ecules in the asymmetric unit of the unit cell. In both mol-ecules, the tetra-hydro-furan rings adopt an envelope conformation with the O atom as the flap and the pyrrolidine rings adopt an envelope conformation. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming sheets lying parallel to the (002) plane. These sheets are connected only by weak van der Waals inter-actions. The most important contributions to the surface contacts are from H⋯H (44.6%), Br⋯H/H⋯Br (24.1%), O⋯H/H⋯O (13.5%) and C⋯H/H⋯C (11.2%) inter-actions, as concluded from a Hirshfeld surface analysis.

Crystal structure and Hirshfeld surface analysis of ethyl (4R,4aS)-2-methyl-5,8-dioxo-6-phenyl-4a,5,6,7,7a,8-hexa-hydro-4H-furo[2,3-f]iso-indole-4-carboxyl-ate

In the title compound, C20H19NO5, the central six-membered ring has a slightly distorted half-chair conformation, with puckering parameters of Q T = 0.3387 (11) Å, θ = 49.11 (19)° and φ = 167.3 (2)°. The conformation of the fused pyrrolidine ring is that of an envelope. Mol-ecules are connected by inter-molecular C-H⋯O hydrogen bonds, C-H⋯π inter-actions and π-π stacking inter-actions [centroid-to-centroid distance = 3.9536 (11) Å, with a slippage of 2.047 Å], forming a three-dimensional network. The most important contributions to the surface contacts are from H⋯H (46.3%), O⋯H/H⋯O (31.5%) and C⋯H/H⋯C (17.3%) inter-actions, as concluded from a Hirshfeld surface analysis.

Crystal structure and Hirshfeld surface analysis of (E)-3-[(4-methyl-benzyl-idene)amino]-5-phenylthiazolidin-2-iminium bromide N,N-di-methyl-formamide monosolvate

In the crystal, each cation is connected to two anions by N—H⋯ Br hydrogen bonds, forming an (8) motif parallel to the (10) plane, while the N,N-di­methyl­formamide mol­ecules are linked to the cations by C—H⋯O contacts.

In the cation of the title salt, C₁₇H₁₈N₃S⁺·Br⁻·C₃H₇NO, the central thia­zolidine ring adopts an envelope conformation with puckering parameters Q(2) = 0.310 (3) Å and φ(2) = 42.2 (6)°. In the crystal, each cation is connected to two anions by N—H⋯ Br hydrogen bonds, forming an R₄²(8) motif parallel to the (10) plane. van der Waals inter­actions between the cations, anions and N,N-di­methyl­formamide mol­ecules further stabilize the crystal structure in three dimensions. The most important contributions to the surface contacts are from H⋯H (55.6%), C⋯H/H⋯C (17.9%) and Br⋯H/H⋯Br (7.0%) inter­actions, as concluded from a Hirshfeld analysis.

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-2-(4-methyl-phen-yl)diazen-1-yl]ethen-yl}-N,N-di-methyl-aniline

In the tile compound, C17H17Cl2N3, the dihedral angle between the benzene rings is 62.73 (9)°. In the crystal, there are no classical hydrogen bonds. Mol-ecules are linked by a pair of C-Cl⋯π inter-actions, forming an inversion dimer. A short inter-molecular HL⋯HL contact [Cl⋯Cl = 3.2555 (9) Å] links the dimers, forming a ribbon along the c-axis direction. The Hirshfeld surface analysis and two-dimensional fingerprint plots reveal that the most important contributions for the crystal packing are from H⋯H (45.4%), Cl⋯H/H⋯Cl (21.0%) and C⋯H/H⋯C (19.0%) contacts.

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-(4-chloro-phen-yl)diazen-yl]ethen-yl}-N,N-di-methyl-aniline

The title compound, C16H14Cl3N3, comprises three mol-ecules of similar shape in the asymmetric unit. The crystal cohesion is ensured by inter-molecular C-H⋯N and C-H⋯Cl hydrogen bonds in addition to C-Cl⋯π inter-actions. Hirshfeld surface analysis and two-dimensional fingerprint plots reveal that Cl⋯H/H⋯Cl (33.6%), H⋯H (27.9%) and C⋯H/H⋯C (17.6%) are the most important contributors towards the crystal packing.

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-(4-fluoro-phen-yl)diazen-yl]ethen-yl}-N,N-di-methyl-aniline

The dihedral angle between the two aromatic rings of the title compound is 64.12 (14)°. The crystal structure is stabilized by a short Cl⋯H contact, C—Cl⋯π and van der Waals inter­actions.

In the title compound, C₁₆H₁₄Cl₂FN₃, the dihedral angle between the two aromatic rings is 64.12 (14)°. The crystal structure is stabilized by a short Cl⋯H contact, C—Cl⋯π and van der Waals inter­actions. The Hirshfeld surface analysis and two-dimensional fingerprint plots show that H⋯H (33.3%), Cl⋯H/H⋯Cl (22.9%) and C⋯H/H⋯C (15.5%) inter­actions are the most important contributors towards the crystal packing.

Crystal structure and Hirshfeld surface analysis of (E)-4-{[2,2-di-chloro-1-(4-meth-oxy-phen-yl)ethen-yl]diazen-yl}benzo-nitrile

In the title compound, C16H11Cl2N3O, the 4-meth-oxy-substituted benzene ring makes a dihedral angle of 41.86 (9)° with the benzene ring of the benzo-nitrile group. In the crystal, mol-ecules are linked into layers parallel to (020) by C-H⋯O contacts and face-to-face π-π stacking inter-actions [centroid-centroid distances = 3.9116 (14) and 3.9118 (14) Å] between symmetry-related aromatic rings along the a-axis direction. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from Cl⋯H/H⋯Cl (22.8%), H⋯H (21.4%), N⋯H/H⋯N (16.1%), C⋯H/H⋯C (14.7%) and C⋯C (9.1%) inter-actions.

Crystal structures and Hirshfeld surface analyses of the two isotypic compounds (E)-1-(4-bromo-phen-yl)-2-[2,2-di-chloro-1-(4-nitro-phen-yl)ethen-yl]diazene and (E)-1-(4-chloro-phen-yl)-2-[2,2-di-chloro-1-(4-nitro-phen-yl)ethen-yl]diazene

In the two isotypic title compounds, C14H8BrCl2N3O2, (I), and C14H8Cl3N3O2, (II), the substitution of one of the phenyl rings is different [Br for (I) and Cl for (II)]. Aromatic rings form dihedral angles of 60.9 (2) and 64.1 (2)°, respectively. Mol-ecules are linked through weak X⋯Cl contacts [X = Br for (I) and Cl for (II)], C-H⋯Cl and C-Cl⋯π inter-actions into sheets parallel to the ab plane. Additional van der Waals inter-actions consolidate the three-dimensional packing. Hirshfeld surface analysis of the crystal structures indicates that the most important contributions for the crystal packing for (I) are from C⋯H/H⋯C (16.1%), O⋯H/H⋯O (13.1%), Cl⋯H/H⋯Cl (12.7%), H⋯H (11.4%), Br⋯H/H⋯Br (8.9%), N⋯H/H⋯N (6.9%) and Cl⋯C/C⋯Cl (6.6%) inter-actions, and for (II), from Cl⋯H / H⋯Cl (21.9%), C⋯H/H⋯C (15.3%), O⋯H/H⋯O (13.4%), H⋯H (11.5%), Cl⋯C/C⋯Cl (8.3%), N⋯H/H⋯N (7.0%) and Cl⋯Cl (5.9%) inter-actions. The crystal of (I) studied was refined as an inversion twin, the ratio of components being 0.9917 (12):0.0083 (12).

Crystal structure and Hirshfeld surface analysis of (E)-3-[(4-chloro-benzyl-idene)amino]-5-phenyl-thia-zolidin-2-iminium bromide

The title salt, C16H15ClN3S+·Br-, is isotypic with (E)-3-[(4-fluoro-benzyl-idene)amino]-5-phenyl-thia-zolidin-2-iminium bromide [Khalilov et al. (2019 ▸). Acta Cryst. E75, 662-666]. In the cation of the title salt, the atoms of the phenyl ring attached to the central thia-zolidine ring and the atom joining the thia-zolidine ring to the benzene ring are disordered over two sets of sites with occupancies of 0.570 (3) and 0.430 (3). The major and minor components of the disordered thia-zolidine ring adopt slightly distorted envelope conformations, with the C atom bearing the phenyl ring as the flap atom. In the crystal, centrosymmetrically related cations and anions are linked into dimeric units via N-H⋯Br hydrogen bonds, which are further connected by weak C-H⋯Br contacts into chains parallel to the a axis. Furthermore, not existing in the earlier report of (E)-3-[(4-fluoro-benzyl-idene)amino]-5-phenyl-thia-zolidin-2-iminium bromide, C-H⋯π inter-actions and π-π stacking inter-actions [centroid-to-centroid distance = 3.897 (2) Å] between the major components of the disordered phenyl ring contribute to the stabilization of the mol-ecular packing. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions for the crystal packing are from H⋯H (30.5%), Br⋯H/H⋯Br (21.2%), C⋯H/H⋯C (19.2%), Cl⋯H/H⋯Cl (13.0%) and S⋯H/H⋯S (5.0%) inter-actions.

Micellization, surface activities and thermodynamics study of pyridinium-based ionic liquid surfactants in aqueous solution

The micellization and surface activity properties of long-chain pyridinium ionic liquids n-alkyl-3-methylpyridinium bromide ([C_nmpy][Br], n: the carbon numbers of hydrophobic tails, n = 12, 14, 16) in aqueous solution were systematically investigated through electronic conductivity measurement, surface tension, and ultraviolet-absorption spectra. The surface chemical parameters and thermodynamics parameters were obtained. The [C_nmpy][Br] ionic liquids exhibit higher surface activities than conventional surfactants with corresponding alkyl chain lengths. The effects of inorganic salts (LiBr, NaBr, MgBr₂), organic alcohols (C₂H₅OH, C₃H₇OH, C₄H₉OH, C₅H₁₁OH) and temperature on the critical micelle concentration (CMC) values of [C_nmpy][Br] aqueous solutions were also investigated. The CMC values remarkably decreased with the addition of inorganic salts. The CMC values increased slightly in the presence of ethanol, but decreased gradually as the chain length of the alcohol increased. The CMC values assumed a trend of decreasing and then increasing with the increase of temperature. The calculation results of thermodynamic parameters show that both adsorption and micellization processes of [C_nmpy][Br] are spontaneous; the enthalpy of [C₁₂mpy][Br] is negative at 293.15 K and becomes negative with temperature increasing. For [C₁₄mpy][Br] and [C₁₆mpy][Br] this transition occurs at 288.15 K and the micellization process is entropy-driven in the investigated temperature range.

This paper contains details on the micellization, surface activity properties, thermodynamics and effects of additives of [C_nmpy][Br].

Effect of Alternation of Chloropropoxy and Propoxy Units and Impact of the Ethylol-Group Number on Properties of Surfactants

Surfactants based on myristic acid, epichlorohydrin, and propylene oxide were obtained in two ways. First, the ester of myristic acid and epichlorohydrin was synthesised, and then with propylene oxide. Second, myristic acid was first reacted with propylene oxide, and then with epichlorohydrin. In both cases, the reactions were carried out at 150–160°C using triethylamine as a catalyst. The obtained chloropropoxy-propoxy and propoxy-chloropropoxy esters of myristic acid are non-ionic surfactants. These products were transformed into cationic surfactants by interaction with several ethanolamines. The specific electroconductance and surface activity of the obtained surfactants, characters that vary with the colloidal–chemical parameters of the surfactants, depended on such factors as the sequence of the epichlorohydrin and propylene oxide units inside the polar group of the obtained ionic surfactants, the presence of the methyl group linked to the N-atom, as well as the number of ethylol groups. It was revealed that the synthesised surfactants possess a property of localising thin (thickness <1 mm) petroleum films spread over different types of water.