Structural studies of PdCl2L2 complexes with fluorinated phosphines, phosphites, and phosphinites as precursors of benzyl bromide carbonylation catalysts, and and X-ray crystal structure of cis-PdCl2[PPh2(OEt)]2

2001 ◽  
Vol 79 (5-6) ◽  
pp. 752-759 ◽  
Author(s):  
Anna M Trzeciak ◽  
Hubert Bartosz-Bechowski ◽  
Zbigniew Ciunik ◽  
Katarzyna Niesyty ◽  
Józef J Ziólkowski
Keyword(s):  
Phenylacetic Acid ◽  
Acid Methyl Ester ◽  
Benzyl Bromide ◽  
Palladium Complexes ◽  
Structural Studies ◽  
Trans Isomers ◽  
X Ray ◽  
Acid Methyl ◽  
Sterically Demanding ◽  
Nmr Methods

PdCl2L2-type complexes with phosphines (L = PPhx(C6F5)3-x (x = 0-3)), phosphites (L = P(OMe)3, P(OPh)3, P(OEt)3), and phosphinites (L = PPh2(OC6F5), PPh2(O-3,5-F2C6H3), PPh2(OEt), PPh2(O-n-Bu), PPh2(O-t-Bu)) were synthesized and characterized by UV-vis and 31P NMR methods. PdCl2L2 complexes with less sterically demanding phosphines (Θ < 140°) exist as cis isomers, which is confirmed by the X-ray structure of cis-PdCl2[PPh2(OEt)]2. These complexes react with CO in the presence of NEt3 forming Pd(CO)xLy (x + y = 4) type carbonyls characterized by IR spectra. All PdCl2L2 complexes studied are active as precursors of benzyl bromide carbonylation catalysts at 40°C and 1 atm CO; however, the activity of the cis isomers is higher than that of the trans isomers. The highest yields of the carbonylation product, phenylacetic acid methyl ester, were obtained using cis-PdCl2[P(OMe)3]2 (92%), cis-PdCl2[P(OPh)3]2 (89%), and cis-PdCl2[PPh2(O-n-Bu)]2 (78%) as catalyst precursors.Key words: palladium complexes, fluorinated phosphines, benzyl bromide carbonylation.

Stereochemistry and Tautomerism of Amino Acid Antagonists: α,γ-Diketo Acids and Esters and their Cyclisation Products

1983 ◽  
Vol 38 (2) ◽  
pp. 220-225 ◽  
Author(s):  
W. S. Sheldrick ◽  
W. Trowitzsch
Keyword(s):  
Amino Acid ◽  
Methyl Ester ◽  
Glyoxylic Acid ◽  
Acid Methyl Ester ◽  
Acid Ethyl Ester ◽  
Enolic Form ◽  
X Ray ◽  
Acid Methyl ◽  
Acid Proton ◽  
Amino Acid Antagonists

Abstract X-ray structural analyses of two α,γ-diketo esters and one α,γ-diketo acid, which are amino acid antagonists, have shown them all to be present in the solid state in the α,β-unsaturated γ-keto enolic form. The structures of the esters β-acetyl-pyruvic acid methyl ester (1) and 2-oxo-cyclopentyl-glyoxylic acid ethyl ester (3) are stabilized by intra-molecular O···H(-O) hydrogen bonds involving the enol proton. In the case of camphor oxalic acid (4) an intramolecular O···H-O hydrogen bond between the γ-keto oxygen and the acid proton is observed. The bond lengths and angles in 1 indicate a significant contribution from the mesomeric β,γ-unsaturated enol form. For comparison purposes the structure of the γ-enol methyl ether of 1, (4-methoxy-2-oxo-pentene)carboxylic acid methyl ester (2) has also been determined. The X-ray structures of the cyclization products of respectively an α,γ-diketo acid and an α,γ-diketo ester are reported.

scholarly journals Micro-focused X-ray diffraction characterization of high-quality [6,6]-phenyl-C61-butyric acid methyl ester single crystals without solvent impurities

2013 ◽  
Vol 1 (36) ◽  
pp. 5619 ◽  
Author(s):  
Giuseppe Paternò ◽  
Anna J. Warren ◽  
Jacob Spencer ◽  
Gwyndaf Evans ◽  
Victoria García Sakai ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Single Crystals ◽  
Butyric Acid ◽  
Acid Methyl Ester ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Acid Methyl ◽  
Butyric Acid Methyl Ester

On the synthesis of cryptosporiopsin: stereochemistry of early intermediates

1982 ◽  
Vol 60 (16) ◽  
pp. 2062-2064
Author(s):  
George M. Strunz ◽  
Peter S. White
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Single Crystal ◽  
Acid Methyl Ester ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
Synthetic Route ◽  
Space Group ◽  
X Ray ◽  
Acid Methyl

The relative configurations of two intermediates in the synthetic route to cryptosporiopsin are clarified through the structure of 3,5-dichloro-1,4-dihydroxy-2-methylcyclopent-2-ene-1-carboxylic acid methyl ester, which was determined by single crystal X-ray techniques. The crystal was monoclinic, space group P21/c, a = 7.352(1), b = 8.868 (3), c = 16.300(7) Å; β = 96.49(2)°. The structure was solved by direct methods and refined to a final R of 0.057.

Transesterification of Kapok Seed Oil (Ceiba pentandra) Using Heterogeneous Catalyst Bimetallic Oxide of Zinc and Copper Supported by γ-Alumina

2020 ◽  
Vol 988 ◽  
pp. 87-94
Author(s):  
Nyoman Puspa Asri ◽  
W.D. Prasetiyo ◽  
A. Kafidhu ◽  
A. Atiqoh ◽  
E.A. Puspitasari ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Zinc Oxide ◽  
Fatty Acid ◽  
Seed Oil ◽  
Acid Methyl Ester ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceiba Pentandra ◽  
Activity Test ◽  
Acid Methyl

Biodiesel was produced from Kapok seed (Ceiba pentandra) oil (KSO) using heterogeneous bimetallic oxide of copper and zinc supported by γ-alumina. The Alumina-supported copper oxide-zinc oxide (CuO-ZnO γ /- Al2O3) further notated by ACZ was synthesized using precipitation, impregnation and gel methods. It also was characterized using the X-ray diffraction (X-RD), and Brunauwer-Emmett Teller (BET) methods. Before being transesterified, KSO was subjected to pretreatment with the aim of minimizing gum and other impurities and reducing the concentration of free fatty acids. The activity test of ACZ catalyst was done by introducing it through the transesterification process of KSO with methanol. The transesterification process was carried out in a laboratory scale three neck flask. The effect of calcinating temperature (°C), and calcinating time of catalyst (h) on the yield of fatty acid methyl ester (FAME) were studied, respectively. The results revealed that the kapok seed oil was worthy and potentially to transesterified into biodiesel using ACZ catalyst with highest FAME yield of 46.67%.

scholarly journals Produksi Biofuel Berbantuan Ultrasonik dari Minyak Kelapa Terkatalisis Ca/gamma-Al2O3 dan K/gamma-Al2O3: Suatu Studi Perbandingan

2021 ◽  
Vol 4 (1) ◽  
pp. 45-56
Author(s):  
Eko Supriadi ◽  
Rahmat Basuki ◽  
Danawati Hadi Prajitno ◽  
Mahfud Mahfud
Keyword(s):  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Ester ◽  
Surface Area ◽  
Acid Methyl Ester ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Methyl

Penelitian ini bertujuan untuk membandingkan doping Kalium (K) dan Kalsium (Ca) pada support γ-Al2O3 dalam produksi biofuel yang berbentuk fatty acid methyl ester (FAME) melalui reaksi transesterifikasi minyak kelapa berbantuan ultrasonik. Reaksi dilakukan dalam tipe reaktor batch dengan perbandingan mol minyak kelapa:etanol = 1:9, dan variasi konsentrasi berat katalis untuk masing-masing katalis K/γ-Al2O­3 dan Ca/γ-Al2O3 terhadap minyak kelapa (0,5%; 1,0%; 1,5%; 2% dan 2,5%), waktu reaksi (30, 60, 90, 120 dan 150 detik), dan frekuensi ultrasonik (20 dan 40 KHz). Keberhasilan doping ditunjukkan pada hasil karakterisasi K/g-Al2O3 ­dan Ca/g-Al2O3 menggunakan X-Ray Diffraction (XRD) yang menghasilkan puncak 2θ karakteristik K (29,70° dan 32,65°) dan Ca (25,35°, 26,77°, dan 27,17°) pada support g-Al2O3 (37,66°, 45,82° dan 67,22°). Karakterisasi menggunakan Surface Area Analyzer (SAA) menunjukkan bahwa katalis K/g-Al2O3 memiliki luas permukaan yang lebih kecil (34,03 m2/g) dibanding Ca/g-Al2O3 (83,77 m2/g), namun diameter pori yang lebih besar (66,12 Å) dibanding Ca/g-Al2O3 (35,22 Å). Katalis K/g-Al2O3 menghasilkan yield FAME yang lebih besar (93,19%) dibanding Ca/γ-Al2O3 (29,76%) pada konsentrasi katalis 2,5%, waktu reaksi 150 detik dan frekuensi ultrasonik 40 kHz. Kualitas FAME terkatalisis K/g-Al2O3 yang dihasilkan memenuhi empat parameter uji: densitas, viskositas kinematic, titik nyala, dan titik tuang sesuai dengan standar SNI 04-7182-2006.

The metabolism of phenylacetic acid by Aspergillus fumigatus ATCC 28282: identification of 2,6-dihydroxyphenylacetic acid

1977 ◽  
Vol 23 (9) ◽  
pp. 1140-1144 ◽  
Author(s):  
Fumiki Yoshizako ◽  
Mitsuo Chubachi ◽  
Atsuo Nishimura ◽  
Teruo Ueno
Keyword(s):  
Methyl Ester ◽  
Aspergillus Fumigatus ◽  
Phenylacetic Acid ◽  
Acid Methyl Ester ◽  
Dihydroxyphenylacetic Acid ◽  
Acid Methyl ◽  
Hydroxyphenylacetic Acid ◽  
New Metabolites

Aspergillus fumigatus ATCC 28282 converted phenylacetic acid into a new dihydroxylated compound (2,6-dihydroxyphenylacetic acid) which was identified as 2,6-dimethoxyphenylacetic acid methyl ester. Two other new metabolites have been isolated also and identified as ortho- hydroxyphenylacetic acid and meta-hydroxyphenylacetic acid.

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