ABSTRACT
Offal tissues carry a lower market value compared to skeletal meats in some global markets. The inclusion of offal in any meat product in the EU and UK must be declared on the label. While many technologies have been applied to the challenge of determining adulteration with offal in meat products, no single method has been recognised and validated as a reliable test to support legislative requirements. This literature review investigated appropriate methods to determine the adulteration of meat with offal. The aim was to identify technologies suitable for future validation to underpin a high throughput, low-cost method suitable for application by enforcement laboratories. Considering all of the methods, technologies which determine elemental composition and peptide markers were particularly highlighted as demonstrating potential for future development to determine a wide range of offal tissues to support the safety and integrity of the food chain.
Subject(s)
Meat Products , Drug Contamination , Food Contamination/analysis , Food Security , Meat/analysis , Meat Products/analysisABSTRACT
The synthesis of deuteriated tri-tert-butyl phosphine is reported. This synthesis is an adaptation of the known procedure for tri-tert-butyl phosphine via a Grignard intermediate.
Subject(s)
Phosphines , Molecular StructureABSTRACT
The first example of triflometallate ionic liquids, named in analogy to chlorometallate ionic liquids, is reported. Trifloaluminate ionic liquids, synthesized from 1-alkyl-3-methylimidazolium triflates and aluminum triflate, were characterized by multinuclear NMR spectroscopy and FT-IR spectroscopy, revealing the existence of oligonuclear, multiply-charged trifloaluminate anions, with multiple bridging triflate modes. Acceptor numbers were determined to quantify their Lewis acidity, rendering trifloaluminate ionic liquids as medium-strength Lewis acids (AN = ca. 65). Used as acidic catalysts in the cycloaddition of 2,4-dimethylphenol and isoprene (molar ratio 2:1) to prepare chromane, trifloaluminate systems outperformed literature systems, showing high activity (conversions 94-99%, selectivities 80-89%) and at low loadings (0.2 mol%) at 35°C. Using these new systems as supported ionic liquid phase (SILP) on multi-walled carbon nanotubes (ionic liquid loading 16 wt%) delivered a recyclable catalytic system, with activity enhanced with respect to the homogenous regime.
ABSTRACT
The presence of the weakly-associated encounter complex in the model frustrated Lewis pair solution (FLP): tris(tert-butyl)phosphine (P(tBu)3) and tris(pentafluorophenyl)borane (BCF) in benzene, was confirmed via PB correlation analysis from neutron scattering data. On average, ca. 5% of dissolved FLP components were in the associated state. NMR spectra of the FLP in benzene gave no evidence of such association, in agreement with earlier reports and the transient nature of the encounter complex. In contrast, the corresponding FLP solution in the ionic liquid, 1-decyl-3-methylimidazolium bistriflamide, [C10mim][NTf2], generated NMR signals that can be attributed to formation of encounter complexes involving over 20% of the dissolved species. The low diffusivity characteristics of ionic liquids is suggested to enhance high populations of encounter complex. The FLP in the ionic liquid solution retained its ability to split hydrogen.
ABSTRACT
Coordination complexes of Lewis acidic metal chlorides AlCl3, GaCl3, InCl3, SbCl3, SnCl4, SnCl2, ZnCl2 and TiCl4 with trioctylphosphine (P888) and trioctylphosphine oxide (P888O) were synthesised. All compounds formed liquid coordination complexes (LCCs) at ambient temperature, although decomposition via a redox mechanism was detected in some cases. The Lewis acidity of the metal chlorides (measured in 1,2-dichloroethane solutions) and the LCCs (measured neat) was quantified by using the Gutmann acceptor number (AN) approach. In general, LCCs were equally or more Lewis acidic than the corresponding metal chlorides. The AN values were compared with the catalytic activity of selected LCCs in a model Diels-Alder reaction. Insight into speciation of LCCs was gained using multinuclear NMR spectroscopy, revealing that most LCCs comprised charge-neutral complexes rather than ionic ones. The relationship between the speciation, Lewis acidity (AN scale) and catalytic activity is discussed in detail. This approach reveals several new, promising catalytic systems, such as P888O-InCl3, with Lewis acidity enhanced compared to chloroindate ionic liquids, and P888O-TiCl4, with hydrolytic stability enhanced with respect to neat TiCl4.
ABSTRACT
The use of 5-phenyltetrazole, a bioisostere of benzoic acid, as an anion source to prepare an ionic liquid is described for the first time. Tetrabutylphosphonium 5-phenyltetrazolate undergoes phase separation from water with lower critical solution temperature phase behavior, in contrast to completely water miscible tetrabutylphosphonium benzoate, and also exhibits strong complexation with water with both eutectic and peritectic behavior that has not previously been observed in ionic liquid+water systems. The anhydrous and trihydrate salts were isolated and characterized by single crystal X-ray diffraction.
ABSTRACT
Until very recently, the term Lewis acidic ionic liquids (ILs) was nearly synonymous with halometallate ILs, with a strong focus on chloroaluminate(III) systems. The first part of this review covers the historical context in which these were developed, speciation of a range of halometallate ionic liquids, attempts to quantify their Lewis acidity, and selected recent applications: in industrial alkylation processes, in supported systems (SILPs/SCILLs) and in inorganic synthesis. In the last decade, interesting alternatives to halometallate ILs have emerged, which can be divided into two sub-sections: (1) liquid coordination complexes (LCCs), still based on halometallate species, but less expensive and more diverse than halometallate ionic liquids, and (2) ILs with main-group Lewis acidic cations. The two following sections cover these new liquid Lewis acids, also highlighting speciation studies, Lewis acidity measurements, and applications.
