Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy. As of 2005, over 3% of the total energy consumption in the United States was supplied by biomass, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy. Similarly, the European Union received 66.1% of its renewable energy from biomass, which thus surpassed the total combined contribution from hydropower, wind power, geothermal energy, and solar power. In addition to energy, the production of chemicals from biomass is also essential; indeed, the only renewable source of liquid transportation fuels is currently obtained from biomass.

The Catalytic Valorization of Lignin for the Production of Renewable Chemicals

Array-based vapour-sensing devices are used to detect and differentiate between chemically diverse analytes. These systems--based on cross-responsive sensor elements--aim to mimic the mammalian olfactory system by producing composite responses unique to each odorant. Previous work has concentrated on a variety of non-specific chemical interactions to detect non-coordinating organic vapours. But the most odiferous, toxic compounds often bind readily to metal ions. Here we report a simple optical chemical sensing method that utilizes the colour change induced in an array of metalloporphyrin dyes upon ligand binding while minimizing the need for extensive signal transduction hardware. The chemoselective response of a library of immobilized vapour-sensing metalloporphyrin dyes permits the visual identification of a wide range of ligating (alcohols, amines, ethers, phosphines, phosphites, thioethers and thiols) and even weakly ligating (arenes, halocarbons and ketones) vapours. Water vapour does not affect the performance of the device, which shows a good linear response to single analytes, and interpretable responses to analyte mixtures. Unique colour fingerprints can be obtained at analyte concentrations below 2 parts per million, and responses to below 100 parts per billion have been observed. We expect that this type of sensing array will be of practical importance for general-purpose vapour dosimeters and analyte-specific detectors (for insecticides, drugs or neurotoxins, for example).

A colorimetric sensor array for odour visualization

An optical method for measurement of dioxygen concentration based upon quenching of phosphorescence.

Supramolecular complex formation imparts stability and substrate selectivity to a simple manganese-porphyrin-based epoxidation catalyst. Lewis acid/Lewis base directed assembly was used to encapsulate the epoxidation catalyst within a supramolecular square structure to form an enzyme-like catalyst system. The "molecular square" takes on the functions of the protein superstructure in an enzyme: it spatially protects the catalytic core from decomposition and induces reaction selectivity.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1521-3773%2820011119%2940%3A22%3C4239%3A%3AAID-ANIE4239%3E3.0.CO%3B2-E

Artificial Enzymes Formed through Directed Assembly of Molecular Square Encapsulated Epoxidation Catalysts

The self-aggregation of cationic porphyrins in aqueous solution has been studied by means of absorption, 1H NMR, and resonance light scattering spectroscopy. The aim of the present study is clarification of the factors which most influence porphyrin self-aggregation in water. Cationic 5,10,15,20-tetrasubstituted porphyrins [PorSub4:  PC3Py (Sub = −(CH2)3-Py+Cl-), PC5Py (Sub = −(CH2)5-Py+Cl-), PC7Py (Sub = −(CH2)7-Py+Cl-), TPPOC2Py (Sub = p-C6H4-O(CH2)2-Py+Br-), and TPPOC3Py (Sub = p-C6H4-O(CH2)3-Py+Br-), where Py+ = N-alkylpyridinium] were used. PC3Py forms a dimer in aqueous solution with or without an added inorganic salt. In the presence of KNO3, dimer formation of PC3Py is dominated by a large and negative enthalpy change. The entropy change for aggregation increases with increasing concentrations of added KNO3, while enthalpy changes are almost constant. The thermodynamic parameters suggest that dimer formation of PC3Py is the result of a large enthalpic gain due to extended van der Waals interaction...

Jean Kim

Papers

On the preparation of metalloporphyrins