2,4,5-Tris(biphenyl-2-yl)-1-bromo­benzene

In the title compound, C42H29Br, the dihedral angles between the central benzene ring and the three attached benzene rings are very similar, lying in the range 52.65 (6)–57.20 (7)°. Of the dihedral angles between the rings of the o-biphenyl substituents, two are similar [46.34 (7) and 47.35 (7)°], while the other differs significantly [64.17 (7)°]. In the crystal, mol­ecules are linked into centrosymmetric dimers by two weak C—H⋯π inter­actions

4-(1-Naphth­yl)benzoic acid

In the title mol­ecule, C17H12O2, the dihedral angle between the mean plane of the benzene ring and that of the naphthalene ring system is 49.09 (6)°. In the crystal structure, mol­ecules are linked to form centrosymmetric dimers via inter­molecular O—H⋯O hydrogen bonds. The hydr­oxy H atom is disordered over two sites with refined occupancies of 0.62 (3) and 0.38 (3)

4,4′-(1,8-Naphthalene-1,8-di­yl)dibenzonitrile

In the title mol­ecule, C24H14N2, the exterior C—C—C angle of the naphthalene ring system involving the two phenyl-substituted C atoms is 126.06 (11)° and the dihedral angles between the mean plane of the naphthalene ring system and those of the benzene rings are 66.63 (5) and 67.89 (5)°. In the crystal, mol­ecules are linked into a ladders by four weak C—H⋯π inter­actions

The supramolecular structures of oximes: an update and the crystal structure of 1,3-diphenyl-propan-2-one oxime

The crystal structure of 1,3-diphenyl-propan-2-one oxime, C15H15NO, is described. The compound crystallises in the monoclinic space group C2/c. Centrosymmetrically related molecules are linked to form R22 (6) dimers. An update, since 2003, of a systematic analysis of the hydrogen bonding patterns in oxime structures with and without competitive O-H...A type acceptors (an acceptor other than the nitrogen of the oxime) functional group is made, taking into account their moieties. The majority of these oximes form dimeric, R22 (6), structures but R33 (8) and R44 (12) were also found. C3 chains which were classically claimed as the usual oxime H-bond pattern were rarely observed. They are mostly found in aldoxime structures

3,3′-Bithio­phene

The title compound, C8H6S2, is disordered [occupancy ratio = 0.839 (2):0.161 (2)] and sits across a centre of symmetry. In the crystal, the mol­ecules are linked by a weak C—H⋯π inter­action

1,3-Diphenyl­propan-2-one (2,4-dinitro­phen­yl)hydrazone

In the title compound, C21H18N4O4, there is an intra­molecular N—H⋯O hydrogen bond between the amino H atom and an O atom of the 2-nitro group of the adjacent benzene ring. The central benzene ring forms dihedral angles of 79.98 (7) and 82.88 (7)° with the two phenyl rings. In the crystal structure, mol­ecules are linked into a three-dimensional network by weak C—H⋯N, C—H⋯O and C—H⋯π inter­actions

Experimental Tests and Preliminary Life Cycle Assessment

Funding Information: Thanks are also due to FCT for the project PTDC/BII-BIO/30884/2017. A.F.P. and M.M.M. thank FCT for funding through the Individual Call to Scientific Employment Stimulus (ref. 2020.01614.CEECIND/CP1596/CT0007 and CEEC-IND/02702/2017, respectively). O.D. is thankful for the Ph.D. grant supported by FCT (2021.05322.BD). Funding Information: This work was funded by Portuguese funds through Fundação para a Ciência e a Tecnologia (FCT/MCTES) in the framework of the projects UIDB/50006/2020, UIDP/50006/2020, and EXPL/BII-BIO/0436/2021 and also by BIP Proof 2022/2023 through UI-Transfer, a cofunding project by European Union through COMPETE 2020-Portugal 2020, CIQUP, Centro de Investigação em Química da Universidade do Porto (UIDB/00081/2020), and IMS, Institute of Molecular Sciences (LA/P/0056/2020). Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.The control of the oxidative stability of biodiesel and blends of biodiesel with diesel is one of the major concerns of the biofuel industry. The oxidative degradation of biodiesel can be accelerated by several factors, and this is most critical in the so-called second generation biodiesel, which is produced from low-cost raw materials with lower environmental impacts. The addition of antioxidants is imperative to ensure the oxidative stability of biodiesel, and these are considered products of high commercial value. The antioxidants currently available on the market are from synthetic origin, so the existence/availability of alternative antioxidants of natural origin (less dependent on fossil sources) at a competitive price presents itself as a strong business opportunity. This work describes and characterizes a sustainable alternative to synthetic antioxidants used in the biodiesel market developed from extracts of vineyard pruning waste (VPW), which are naturally rich in phenolic compounds with antioxidant properties. A hydrothermal extraction process was applied as a more efficient and sustainable technology than the conventional one with the potential of the extracts as antioxidant additives in biodiesel evaluated in Rancitech equipment. The VPW extract showed comparable antioxidant activity as the commercial antioxidant butylated hydroxytoluene (BHT) typically used in biodiesel. The stability of the biodiesel is dependent from the amount of the extract added. Further, for the first time, the assessment of the environmental impacts of using natural extracts to control the oxidative stability of biodiesel in the production process is also discussed as a key factor of the process environmental sustainability.publishersversionpublishe

N′-Benzoyl-N,N-diethyl­thio­urea: a monoclinic polymorph

In the crystal of the title compound, C12H16N2OS, inversion dimers linked by pairs of N—H⋯S hydrogen bonds occur, generating R 2 2(8) loops. The mol­ecules are also linked by weak C—H⋯O hydrogen bonds. The structure is isostructural with that of N′-benzoyl-N,N-diethyl­seleno­urea [Bruce et al. (2007 ▶). New J. Chem. 31, 1647–1653]

Evidence of nanostructuration from the heat capacities of the 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid series

In the present work, the heat capacities at T = 298.15 K of 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide, [C(N/2)C(N/2)im][NTf2], were measured, for the first time, using a high-precision heat capacity drop calorimeter, with an uncertainty of less than 0.15%. Based on the obtained results, it was possible to evaluate the effect of the cation symmetry on the heat capacity data through a comparative analysis with the [C(N-1)C(1)im][NTf2] ionic liquid series. The molar heat capacities of the [C(N/2)C(N/2)im][NTf2] ionic liquids series present a less pronounced deviation from the linearity along the alkyl chain length than the asymmetric based ionic liquids series. Lower molar heat capacities for the symmetric than the asymmetric series were observed, being this difference more evident for the specific and volumic heat capacities. As observed for the [C(N-1)C(1)im][NTf2] series, a trend shift in the heat capacities at [C(6)C(6)im][NTf2] was found that reflects the impact of nonpolar region nanostructuration on the thermophysical properties of the ionic liquids. The profile of the two regions is in agreement with the expected effect arising from the nanostructuration in ionic liquids. The results obtained in the present work show a clear indication that for the symmetric series, [C(N/2)C(N/2)im][NTf2], the starting of the liquid phase nanostructuration/alkyl chain segregation occurs around [C(6)C(6)im][NTf2]. (C) 2013 AIP Publishing LLC