Search results for "PAPER"

A triclinic polymorph of (−)-(S)-N-benzyl-2-[(R)-6-fluorochroman-2-yl]-2-hydroxyethanaminium bromide

2013

The title salt, C18H21FNO2+·Br−, determined at 115 K, crystallizes in the triclinic space groupP1. The previously reported polymorph occurs in the monoclinic space groupP21and has two independent molecules in the asymmetric unit [Peeterset al.(1993).Acta Cryst.C49, 2157–2160]. In the title molecule, the pyran rings adopt half-chair conformations. The absolute configuration isSfor the hydroxy-bearing C atom andRfor the asymmetric C atom in the dihydropyran unit. In the crystal, the components are linked by N—H...Br and O—H...Br hydrogen bonds, forming chains along thec-axis direction. The crystal studied was refined as an inversion twin.

2-(Mesitylmethylsulfanyl)pyridine N-oxide monohydrate

2008

In the title compound, C15H17NOS·H2O, the benzene and pyridine rings form a dihedral angle of 71.18 (2)°. The intramolecular S...O distance [2.737 (3) Å] is shorter than expected and, in terms of hybridization principles, the N—C—S angle [114.1 (2)°] is smaller than expected. The crystal structure is stabilized by intermolecular O—H...O and weak C—H...O hydrogen bonds. In addition, weak π–π stacking interactions with a centroid–centroid distance of 3.778 (3) Å are also observed.

N-(2,6-Dimethylanilino)-5,6-dihydro-4H-1,3-thiazin-3-ium chloride monohydrate

2008

In the title compound, alternatively called xylazine hydro-chloride monohydrate, C(12)H(17)N(2)S(+)·Cl(-)·H(2)O, the six-membered thia-zine ring is in a half-chair conformation. In the crystal structure, six component centrosymmetric clusters are formed via inter-molecular O-H⋯Cl, N-H⋯O and N-H⋯Cl hydrogen bonds involving xylazine cations, chloride anions and water mol-ecules.

Kinetics of nitrogen removal in a MBR nutrient removal activated sludge system

2006

The application of membrane bioreactor (MBR) technology to biological nutrient removal (BNR) activated sludge (AS) systems is limited and uncertainty exists as to the impact of the conditions induced by the membranes on the biologically mediated processes of nutrient removal. Two main conditions associated with MBRs are (1) high total suspended solids (TSS) concentrations (8–20 g/L) and (2) different selection pressures due to biomass retention not being based on settleability, compared with conventional systems with secondary settling tanks (SSTs). Recently, Ramphao et al. [1] concluded that incorporating membranes in BNR AS makes a profound difference to the design of the system. Previous…

Zur Frage der Resorption von Polyphosphaten

1965

Zur Klarung der Frage nach der Resorption von Polyphosphaten wurden Losungen von32P-markiertem Diphosphat, Triphosphat und einem Natriumpolyphosphat mit 64% P2O5 Ratten mit der Schlundsonde appliziert. Nach einer Verweildauer von 1, 2, 4, 8 und 16 Std dieser Polyphosphate im Magen-Darmtrakt wurden die Ratten dekapitiert und das erhaltene Frischblut radiometrisch und papierchromatographisch untersucht. Im enteiweisten Vollblut konnten nur Monophosphat und AMP nachgewiesen werden, d. h. es wird ausschlieslich anorganisches Monophosphat resorbiert, das durch enzymatische Aufspaltung der Polyphosphate gebildet wird. Dieses Monophosphat wird dann in die organische Bindung der AMP ubergefuhrt und…

Host-guest complexes of conformationally flexible

2018

Host–guest complexes of C-hexyl-2-bromoresorcinarene (BrC6) with twelve potential aromatic N-oxide guests were studied using single crystal X-ray diffraction analysis and 1H NMR spectroscopy. In the solid state, of the nine obtained X-ray crystal structures, eight were consistent with the formation of BrC6-N-oxide endo complexes. The lone exception was from the association between 4-phenylpyridine N-oxide and BrC6, in that case the host forms a self-inclusion complex. BrC6, as opposed to more rigid previously studied C-ethyl-2-bromoresorcinarene and C-propyl-2-bromoresorcinarene, undergoes remarkable cavity conformational changes to host different N-oxide guests through C–H···π(host) intera…

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length.

2010

Due to the low solubility of poly(glycolic acid) (PGA), its use is generally limited to the synthesis of random copolyesters with other hydroxy acids, such as lactic acid, or to applications that permit direct processing from the polymer melt. Insolubility is generally observed for PGA when the degree of polymerization exceeds 20. Here we present a strategy that allows the preparation of PGA-based multi-arm structures which significantly exceed the molecular weight of processable oligomeric linear PGA (<1000 g/mol). This was achieved by the use of a multifunctional hyperbranched polyglycerol (PG) macroinitiator and the tin(II)-2-ethylhexanoate catalyzed ring-opening polymerization of gly…

PENGARUH PEMANFAATAN LIMBAH CAIR PABRIK KELAPA SAWIT TERHADAP SIFAT KIMIA DAN FISIKA TANAH PADA LAHAN PERKEBUNAN KELAPA SAWIT MILIK PT.PMP KABUPATEN …

2019

Palm oil mill effluent (POME) is the most abundant waste produced from palm oil mills. POME waste products from palm oil mills can pollute the surrounding environment. The main objective of this study was to determine the use of POME on soil fertility and increase the growth of oil palm plants and minimize negative impacts on the environment. The results of the research obtained are a combination of primary data (results of analysis carried out in oil palm plantations owned by PT PMP, Maybrat Regency before the POME application) and secondary data (results of analysis carried out at Angsana Estate oil palm plantations, South Kalimantan after POME  application). The results obtained indicate…

Dynamic response in pH and the transient behavior of some chemical elements in pulp-water suspensions

1999

The Orange Peel: An Outstanding Source of Chemical Resources

2021

Citrus sinensis (L.) Osbeck is a very common cultivar belonging to the Rutaceae family. It is largely diffused in several areas of the world characterized by mild to warm climate conditions. Its abundant worldwide production (up to 107 Tons. per year) and consumption both as the edible part of the fruit and as several types of derivative products imply the production of a huge amount of waste, such as the fruit pomace. Several ways of recycling this material have been developed in recent years: employment as fertilizer, fodder ingredient, and even cloth material. However, the chemical added value of Citrus sinensis peel has been underestimated despite the diversified and significant content…