A New Approach to the Anodic Decarboxylation of Unsaturated Dicarboxylic Acids. Part 1: Fumaric, Maleic and Acetylenedicarboxylic Acids.

The dipotassium salts of maleic, fumaric and acetylenedicarboxylic acids were electrooxidized and the reaction products were analyzed qualitatively and quantitatively by UV/VIS and FT-IR spectroscopy. Acetylene, carbon dioxide and carbon monoxide, along with polyynes, are the products obtained from maleic and fumaric acids. The best acetylene yields are obtained from fumaric acid and not from maleic acid, which gives the highest yield of carbon dioxide. High concentration and high current density lead to the formation of carbonaceous matter containing carbyne recognizable by triple-bond stretching. Anodic oxidation of acetylenedicarboxylic acid produces only a mixture of carbon dioxide, carbon monoxide and soluble polyynes; no free acetylene was detected. A total of 15 Chemical reactions with their free energy were studied to explain the reaction products of anodic oxidation

Electrosynthesis of Allene (Propadiene) and of Propyne (Methylacetylene) through the Anodic Decarboxylation Reaction (Part 2)

The anodic decarboxylation reaction is a general reaction that can be applied with success to several suitable precursors. This work presents the electrochemical synthesis of allene by anodic oxidation of potassium itaconate. It is also shown that the anodic oxidation of potassium citraconate produces propyne. In both cases, unsaturated hydrocarbons were formed together with CO and CO2. The electrooxidation of potassium crotonate leads to a simultaneous formation of propyne and allene (the latter in considerably smaller amounts than the former). Also in this case, formation of the unsaturated hydrocarbons is accompanied by the formation of CO and CO2

Synthesis And Characterization Of Polyynes End-Capped By Biphenyl Groups ({\Alpha},{\Omega}-Biphenylpolyynes)

Stable polyyne chains terminated with biphenyl end groups (a,u-biphenylpolyynes) were synthesized in a single step through a simple procedure by using the Cadiot-Chodkiewicz reaction conditions. The a,ubiphenylpolyynes were separated through HPLC analysis and identified by means of their electronic absorption spectra. The a,u-biphenylpolyynes were studied by FT-IR and Raman spectroscopy and the spectral interpretation was supported with DFT calculations. A peculiarly low reactivity of a,u-biphenylpolyynes with ozone was observed.Comment: The research leading to these results has received funding from the European Research Council Consolidator Grant EspLORE (ERC-2016-CoG Grant No.724610

Biodiesel as a Plasticizer of a SBR-Based Tire Tread Formulation

The solubility parameter of a series of methyl esters of fatty acids, the components of biodiesel, was calculated using the group incremental method proposed by Van Krevelen. The solubility parameter of biodiesel was compared with that of a series of rubbers like EPDM, butyl rubber, polyisoprene, polybutadiene, SBR (with different content of styrene), and nitrile rubber (with different content of acrylonitrile) showing that biodiesel is an effective solvent of all the above mentioned rubbers with the exclusion of nitrile rubber. Indeed, it was experimentally verified that polyisoprene, polybutadiene and SBR are easily soluble in biodiesel while polystyrene gives a cloudy solution. Considerations on the solubility parameter of the biodiesel and of a series of rubbers have led to the conclusion that biodiesel behaves essentially as an internal lubricant in a diene rubber matrix, the same situation occurs with the common aromatic mineral oil plasticizer known as T-RAE. The experimental evaluation of biodiesel as plasticizer in an SBR-based rubber compound in comparison to an aromatic mineral oil have led to the primary conclusion that biodiesel is reactive with the sulphur curing agent subtracting sulphur to the crosslinking polymer chains and leading to a vulcanizatewith lower moduli, tensile and hardness and higher elongationsin comparison to a reference compound fully plasticized with an aromatic mineral oil. However, biodiesel seems a good low temperature plasticizer because the low elastic modulus observed is desired in a winter tire tread for a good grip on snow and ice. The present work is only an exploratory work, and the tire tread formulation with biodiesel was not optimized

A New Approach to the Anodic Decarboxylation of Unsaturated Dicarboxylic Acids. Part 1: Fumaric, Maleic and Acetylenedicarboxylic Acids.

The dipotassium salts of maleic, fumaric and acetylenedicarboxylic acids were electrooxidized and the reaction products were analyzed qualitatively and quantitatively by UV/VIS and FT-IR spectroscopy. Acetylene, carbon dioxide and carbon monoxide, along with polyynes, are the products obtained from maleic and fumaric acids. The best acetylene yields are obtained from fumaric acid and not from maleic acid, which gives the highest yield of carbon dioxide. High concentration and high current density lead to the formation of carbonaceous matter containing carbyne recognizable by triple-bond stretching. Anodic oxidation of acetylenedicarboxylic acid produces only a mixture of carbon dioxide, carbon monoxide and soluble polyynes; no free acetylene was detected. A total of 15 Chemical reactions with their free energy were studied to explain the reaction products of anodic oxidation

Synthesis, Characterization, and Modeling of Naphthyl-Terminated sp Carbon Chains: Dinaphthylpolyynes

We report a combined study on the synthesis, spectroscopic characterization and theoretical modelling of a series of {\alpha},{\omega}-dinaphthylpolyynes. We synthesized this family of naphtyl-terminated sp carbon chains by reacting diiodoacetylene and 1-ethynylnaphthalene under the Cadiot-Chodkiewicz reaction conditions. By means of liquid chromatography (HPLC), we separated the products and recorded their electronic absorption spectra, which enabled us to identify the complete series of dinaphthylpolyynes Ar-C2n-Ar (with Ar = naphthyl group and n = number of acetilenic units) with n ranging from 2 to 6. The longest wavelength transition (LWT) in the electronic spectra of the dinaphthylpolyynes red shifts linearly with n away from the LWT of the bare termination. This result is also supported by DFT-LDA simulations. Finally, we probed the stability of the dinaphthylpolyynes in a solid-state precipitate by Fourier-transform infrared spectroscopy and by differential scanning calorimetry (DSC).Comment: This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in [J. Phys. Chem. B], copyright \c{opyright} American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021%2Fjp104863

Amino Acids in Comets and Meteorites: Stability under Gamma Radiation and Preservation of Chirality

Amino acids in solar system bodies may have played a key role in the chemistry that led to the origin of life on Earth. We present laboratory studies testing the stability of amino acids against gamma radiation photolysis. All the 20 chiral amino acids in the levo form used in the proteins of the current terrestrial biochemistry have been irradiated in the solid state with gamma radiation to a dose of 3.2 MGy which is the dose equivalent to that derived by radionuclide decay in comets and asteroids in 1.05x109 years. For each amino acid the radiolysis degree and the radioracemization degree was measured by differential scanning calorimetry (DSC) and by optical rotatory dispersion (ORD) spectroscopy. From these measurements a radiolysis rate constant kdsc and a radioracemization rate constant krac have been determined for each amino acid and extrapolated to a dose of 14 MGy which corresponds to the expected total dose delivered by the natural radionuclides decay to all the organic molecules present in comets and asteroids in 4.6x109 years, the age of the Solar System. It is shown that all the amino acids studied can survive a radiation dose of 14 MGy in significant quantity although part of them are lost in radiolytic processes. Similarly, also the radioracemization process accompanying the radiolysis does not extinguish the chirality. The knowledge of the radiolysis and radioracemization rate constants may permit the calculation of the original concentration of the amino acids at the times of the formation of the Solar System starting from the concentration found today in carbonaceous chondrites. For some amino acids the concentration in the presolar nebula could have been up to 6 times higher than currently observed in meteorites.Comment: 20 pages, 5 figures, submitted to MNRA

Performance of the ALICE luminosity levelling software architecture in the Pb-Pb physics run

Luminosity leveling is performed in the ALICE experi-ment of the Large Hadron Collider (LHC) in order to limitthe event pile-up probability, and ensure a safe operation forthe detectors. It will be even more important during Run3 when 50 KHz Pb ion-Pb ion (Pb-Pb) collisions will bedelivered in IP2. On the ALICE side, it is handled by theALICE-LHC Interface project, which also ensures an onlinedata exchange between ALICE and the LHC. An automated luminosity leveling algorithm was developed for the proton-proton physics run, and was also deployed for the Pb-Pb run with some minor changes following experience gained. The algorithm is implemented in the SIMATIC WinCC SCADA environment, and determines the leveling step from measured beam parameters received from the LHC, and the luminosity recorded by ALICE. In this paper, the softwarearchitecture of the luminosity leveling software is presented,and the performance achieved during the Pb-Pb run and Vander Meer scans is discussed.peer-reviewe