Thermal Analysis of Plastics Used in the Food Industry

Fires in landfills, where used plastic packaging waste is discarded, have shown how great a fire hazard these types of materials pose. In this study, the course of thermo-oxidation of samples made of polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) based plastics was determined. Based on an analysis of the dissociation energy of bonds between atoms in a polymer molecule, the mechanisms responsible for the character and course of degradation were observed. It was found that the degradation rate of PP and PS could be a result of the stability of C-H bonds on the tertiary carbon atom. In the case of PS, due to facilitated intramolecular hydrogen transfer, stabilization of hydroperoxide, and formation of a stable tertiary alcohol molecule, the onset of degradation is shifted towards higher temperatures than in the case of PP. Notably, the PP fragmentation occurs to a greater extent due to the easier course of β-scission. In addition, it was found that during a fire, the least amount of heat would be generated by thermo-oxidation of PS-based plastics. This is a result of the formation of a styrene molecule during decomposition that, due to the high stability of bonds in the aromatic ring, escapes from the combustion zone without oxidation. It has been proven that the greatest thermal effect accompanies PET decomposition, during which a phenyl radical is produced, where the C-H bonds break more easily in comparison with the bonds of an intact ring.

An efficient synthesis of furan-3(2 H )-imine scaffold from alkynones

A novel efficient method to generate spiro furan-3(2 H )-imine derivatives is established by the reaction between the α , β -unsaturated ketones and aniline derivatives. The reaction involves 1,4- addition of aniline followed by the subsequent intramolecular cyclization mediated by tertiary alcohol to produce the furan-3(2 H )-imine. All the synthesized compounds are characterized using nuclear magnetic resonance and high-resolution mass spectrometry (HRMS).

An efficient alternative to the total synthesis of isophytol

: An improved and alternative method for the total synthesis of isophytol from citral via using pseudoionone intermediate was developed and described in this manuscript. This alternative commercially viable approach involved six steps and represents an alternative commercially viable over existing published synthetic methods in the literature. This goal was achieved by developing and optimizing an efficient and high yield procedure for the synthesis of a key intermediate i.e., 6,10,14 trimethylpentadectrimethylpentadec-5-en-2-one by reacting 2-methoxypropene with a tertiary alcohol (3,7,11 trimethyldodec-1-ene-3-ol). Isophytol was provided in 58-60% overall yield from citral with >99% purity, evaluated by TLC, GC, and NMR.

Visible-Light Induced Singlet Nucleophilic Carbenes: Rapid and Mild Access to Fluorinated Tertiary Alcohol Derivatives

Singlet nucleophilic carbenes (SNCs) that contain only one heteroatom donor remain underexplored and underutilized in chemical synthesis. To discover new synthetic strategies that harness these SNCs as reactive intermediates, aromatic or aliphatic siloxy carbenes represent excellent model substrates as they can be readily generated photochemically from stable acyl silane precursors. We herein report the discovery that photochemically generated siloxy carbenes undergo 1,2-carbonyl addition to trifluoromethyl ketones, followed by a silyl transfer process to afford benzoin-type products. This new transformation is a rare example of the use of ketones as trapping reagents for SNC intermediates and delivers an efficient, user-friendly and scalable process to access fluorinated tertiary alcohol derivatives driven by only light, circumventing the use of catalysts or additives.

Visible-Light Induced Singlet Nucleophilic Carbenes: Rapid and Mild Access to Fluorinated Tertiary Alcohol Derivatives

Singlet nucleophilic carbenes (SNCs) that contain only one heteroatom donor remain underexplored and underutilized in chemical synthesis. To discover new synthetic strategies that harness these SNCs as reactive intermediates, aromatic or aliphatic siloxy carbenes represent excellent model substrates as they can be readily generated photochemically from stable acyl silane precursors. We herein report the discovery that photochemically generated siloxy carbenes undergo 1,2-carbonyl addition to trifluoromethyl ketones, followed by a silyl transfer process to afford benzoin-type products. This new transformation is a rare example of the use of ketones as trapping reagents for SNC intermediates and delivers an efficient, user-friendly and scalable process to access fluorinated tertiary alcohol derivatives driven by only light, circumventing the use of catalysts or additives.

4-Fluoro-2-({[(2R)-1-hydroxy-1,1,3-triphenylpropan-2-yl]imino}methyl)phenol

The title compound, C28H24FNO2, crystallizes in the orthorhombic space group P212121. A hydrogen-bonding network between the tertiary alcohol group and the fluoro substituent results in [010] chains in the solid state.