Fractionation of soluble portion of reductively alkylated bituminous coals

1986 ◽  
Vol 51 (5) ◽  
pp. 1071-1082 ◽  
Author(s):  
Maya D. Stefanova ◽  
Ivo Lang
Keyword(s):  
Molecular Weight ◽  
Thin Layer ◽  
Elemental Composition ◽  
Silica Gel ◽  
Nmr Spectra ◽  
Benzene Solution ◽  
Polar Compounds ◽  
H Nmr ◽  
Hcl Gas ◽  
Bituminous Coals

Five bituminous coals were reductively alkylated with potassium and 1-butyl iodide in THF. The benzene soluble portion of reductively butylated coals were separated into the saturates, aromatics, neutral heterocyclics, ethers and polar compounds on a silica gel column. From the saturates, the n-alkanes were isolated by the thin-layer and column chromatography on silica gel, and then analyzed by GC. The aromatics were fractionated on a dual packed SiO2/Al2O3 column. The mono- and diaromatic fractions obtained were studied by GC-MS method. The non-hydrocarbon and polar compounds were charcterized by elemental composition, VPO molecular weight and both IR and 1H NMR spectra. The asphaltenes from one reductively butylated coal were fractionated into basic and acidic/neutral parts after bubbling dry HCl gas through their benzene solution. A concept that benzene eluates collect C-alkylation products and diethyl ether + THF mixtures collect the products of O-alkylation was evolved. The ratio of C-alkylation to O-alkylation was found to be a function of the C content of the initial coals.

Structure of sodium tetracaprolactamatoaluminate. 1H NMR spectra of sodium isobutylcaprolactamatoaluminates

1983 ◽  
Vol 48 (10) ◽  
pp. 2728-2734 ◽  
Author(s):  
Otomar Kříž ◽  
Jiří Fusek ◽  
Bohuslav Čásenský
Keyword(s):  
Molecular Weight ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Benzene Solution ◽  
Sodium Atom ◽  
1H Nmr Spectra ◽  
H Nmr

Sodium tetracaprolactamatoaluminate (I) exists in benzene solution predominantly as a dimer. Its structure was proposed on the basis of molecular weight studies, infrared, and 1H NMR spectra of sodium isobutylcaprolactamatoaluminates (II). Two modes of dimerization are supposed: an eight-membered cyclic caprolactam bridge between two aluminum atoms or the coordination of the caprolactam ligands belonging to two different aluminum atoms to one sodium atom.

Changes in elemental composition, molecular weight and1H NMR spectra of the water-extractable hydrophobic acid fraction in Cambisol with season and soil depth

2006 ◽  
Vol 52 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Daichi Asakawa ◽  
Hidemasa Mochizuki ◽  
Yukiko Yanagi ◽  
Takeshi Suzuki ◽  
Seiya Nagao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Elemental Composition ◽  
Nmr Spectra ◽  
Soil Depth ◽  
Acid Fraction ◽  
Water Extractable

The Identification of Rubber Compounding Ingredients by Using Thin Layer Chromatography

1983 ◽  
Vol 56 (5) ◽  
pp. 1080-1095 ◽  
Author(s):  
B. J. Gedeon ◽  
T. Chu ◽  
S. Copeland
Keyword(s):  
Molecular Weight ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Easy Method ◽  
Mobile Phases ◽  
Rf Values ◽  
Visualization Systems ◽  
Layer Chromatography

Abstract TLC is a quick, easy method to the identification of rubber compounding ingredients. Both silica gel absorbent and C18 absorbent are suitable for these identifications. With the mobile phases used in this study, a better separation of antioxidants is possible using silica gel absorbent. Work should be continued on finding suitable mobile phases for the C18 absorbent, since the Rf values are more reproducible. For those separations that require a separation of compounds of varying molecular weight, the C18 absorbent is superior to silica gel absorbent. The visualization systems that have been developed for use with silica gel absorbent are suitable for use with C18 absorbent. These systems give the same colors for either absorbent.

Antimycobacterial thiobenzanilides

1990 ◽  
Vol 55 (1) ◽  
pp. 307-316 ◽  
Author(s):  
Karel Waisser ◽  
Nestor Houngbedji ◽  
Miloš Macháček ◽  
Miroslav Sekera ◽  
Josef Urban ◽  
...  
Keyword(s):  
Silica Gel ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Antimycobacterial Activity ◽  
Uv Spectra ◽  
Mycobacterium Kansasii ◽  
Aromatic Rings ◽  
H Nmr ◽  
Hammett Constants ◽  
Thioamide Group

A group of 30 thiobenzanilides active against Mycobacterium kansasii have been synthesized and their 1H NMR and UV spectra and RM values (TLC on silica gel impregnated with methylsilicone oil) have been measured. From the correlation between the chemical shifts of the thioamide proton in the 1H NMR spectra and the Hammett constants it can be concluded that the substituents in both aromatic rings uniformly affect the electron density of the thioamide group. The antimycobacterial activity is probably connected with local molecular parameters and can be considered to be approximately additive with respect to both parts of the molecule.

Copolymerization of 5-norbornene-2-metheneoxy-trimethylsilyl with methyl 5-norbornene-2-carboxylate catalyzed by a novel Ni(benzocyclohexan-ketonaphthylimino)2/B(C6F5)3) system

2012 ◽  
Vol 32 (6-7) ◽  
pp. 415-423
Author(s):  
Xiaofeng Wang ◽  
Xiaohui He ◽  
Defu Chen ◽  
Yiwang Chen
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Nmr Spectra ◽  
Catalyst System ◽  
Narrow Molecular Weight Distribution ◽  
Complex Catalyst ◽  
Good Thermal Stability ◽  
H Nmr ◽  
Catalyst Systems ◽  
C Nmr

Abstract Copolymerization of 5-norbornene-2-metheneoxy-trimethylsilyl [NB-CH2OSi(CH3)3] with norbornene (NB) or methyl 5-norbornene-2-carboxylate (NB-COOCH3) was carried out in toluene by using novel nickel(II) complex catalyst systems, Ni(benzocyclohexan-ketonaphthylimino)2/B(C6F5)3 [Ni(bchkni)2/B(C6F5)3]. The catalyst system showed high activity on the copolymerization of NB-CH2OSi(CH3)3 with NB (2.3–3.3×104 gpolymer/molNi·h) and NB-CH2OSi(CH3)3 with NB-COOCH3(0.5–3.0×104 gpolymer/molNi·h). However, the solubility of copolymers of NB-CH2OSi(CH3)3 with NB and NB-CH2OSi(CH3)3 with NB-COOCH3, which contain 18.7–86.7 mol% of NB-CH2OSi(CH3)3, was too poor to characterize. The achieved copolymers were confirmed to be vinyl-addition copolymers through the analysis of FTIR, 1H NMR, and 13C NMR spectra. The incorporation rate was 8.7–86.7 mol% at a content of 10–90 mol% of the NB-CH2OSi(CH3)3 in the monomer feeds ratios. The obtained ester functionalized NB copolymer containing 8.7–18.7 mol% of NB-CH2OSi(CH3)3 showed a moderate molecular weight (Mw=1.6–6.0×104 g/mol) and relative narrow molecular weight distribution (Mw/Mn=1.6–2.2). Thermogravimetry (TGA) analyses results showed that the copolymers exhibited good thermal stability (Td=330–350°C) and were noncrystalline by WAXD analyses results.

scholarly journals Determination of Hydrocarbon Types in Petroleum and Coal-Derived Products by Thin-Layer Chromatography/Densitometry

2000 ◽  
Vol 83 (6) ◽  
pp. 1474-1479 ◽  
Author(s):  
Vicente L Cebolla ◽  
Luis Membrado ◽  
Jesús Vela ◽  
Rosa Garriga ◽  
Patrick Henrion ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Polar Compounds ◽  
Petroleum Products ◽  
Excitation Wavelength ◽  
Standard Calibration ◽  
Alternative Detection ◽  
Middle Distillates ◽  
Layer Chromatography

Abstract Different methodologies based on thin-layer chromatography (TLC)/densitometry were used to separate and quantitate hydrocarbon types in middle distillates (gas oil), heavy distillates (lubricant) from petroleum, and coal-derived products. Thus, petroleum products were separated into saturates and aromatics by development, using n-hexane (9 min) followed by dichloromethane (4.5 min), of silica gel plates impregnated with berberine sulfate. Detection of saturates and aromatics was performed by fluorescence scanning using 365 nm as the excitation wavelength. Alternative detection of aromatics can be performed on either silica gel or berberine-impregnated plates by using ultraviolet (UV) densitometry at 250 nm. On the other hand, polar coal-derived products were separated into aromatics, polar compounds, and uneluted components by using silica gel plates and development with toluene (12 min), followed by dichloromethane–methanol (95 + 5, v/v), with detection by UV densitometry at 250 nm. In all cases, external standard calibration was used for quantitation. Results were validated by using standard methods or well-established techniques of the petrochemical industry. The potential usefulness of TLC/densitometry is discussed.

Über das Verhalten von 5-Hydroxy-Kawainen gegen Alkali / Behaviour of 5-Hydroxykawain Derivatives under Mild Alkaline Conditions

1978 ◽  
Vol 33 (9) ◽  
pp. 1020-1025 ◽  
Author(s):  
R. Hansel ◽  
A. Pelter ◽  
M. T. Ayoub ◽  
R. Reinhardt
Keyword(s):  
Silica Gel ◽  
Potassium Hydroxide ◽  
Nmr Spectra ◽  
Ring Contraction ◽  
X Ray ◽  
H Nmr ◽  
Contraction Process ◽  
Alkaline Conditions

Treatment of cis-dihydroxykawainol = rel (5R, 6R)-(±)-5-hydroxy-4-methoxy-6- phenylethyl-5,6-dihydro-2H-pyran-2-on (cis-3) with potassium hydroxide in methanol (2.5%, 1 h, room temp.) leads to a 1:1 mixture of the corresponding erythro-butenolide 7 and threo-butenolide 8 by a ring contraction process that may have analogies with the biosynthesis of the piperolides 15. Trans-3 gives the same yields (about 70%) of the same mixture (7 and S), which can be separated by silica-gel columns. Starting from mixtures of cis-5-hydroxykawain (cis-4) and trans-5-hydroxykawain (trans-4), there were prepared and described the two epimeric dehydro-butenolides 9 and 10 and their O-methylderivatives 11 and 12. The threo- and erythro-series show consistant differences between J5,6 and the 1H NMR spectra. The constitution and configuration of (± )-erythro-5- (1-methoxy-3-phenylallyl)-4-methoxy-2(5H)-furanone (11) were established by X-ray analysis.

1: 13- und 1: 14-Heteropolyvanadate des Phosphors(V) / 1:13- and 1:14- Heteropolyvanadates of Phosphorus(V)

1976 ◽  
Vol 31 (12) ◽  
pp. 1585-1591 ◽  
Author(s):  
Fritz Preuss ◽  
Heinrich Schug
Keyword(s):  
Molecular Weight ◽  
Nmr Spectra ◽  
Soluble Salts ◽  
Oh Groups ◽  
H Nmr ◽  
Stable Species ◽  
Wide Range ◽  
Wide Line

Deep red heteropolyvanadates of phosphorus(V) n M2O:P2O5: 13 V2O5 · aq (n = 3, 5, 6; M = Na, K, Rb, Cs, NH4) and n M2O: P2O5: 14 V2O5 · aq (n = 4, 7; M = K, Rb, Cs, NH4, (n-C4H9)4N) were prepared. Recrystallization of 1: 13- and 1: 14-heteropolyvanadates and determination of molecular weight by ultracentrifuge technique in solutions from V2O5 and NaH2PO4 indicate 1: 14-heteropolyvanadate ions to be stable species over a wide range of pH, while 1: 13-heteropolyvanadate ions are only stabilized in higher acidified solutions containing H2PO4- or as slightly soluble salts. Wide line 1H NMR spectra are interpreted in terms of OH groups and H2O of cristallization, the isolated heteropolyvanadates of both series consisting of protonated anions; the basicity of heteropolyvanadic acids of phosphorus(V) is unknown.

Synthesis of Some 2-Aminonitroethanes via Silica Gel-Catalyzed Nitro-Mannich Reaction

2006 ◽  
Vol 61 (9) ◽  
pp. 1162-1165 ◽  
Author(s):  
Ali S. Mahasneh
Keyword(s):  
Silica Gel ◽  
Elemental Analysis ◽  
Mannich Reaction ◽  
Nmr Spectra ◽  
One Pot ◽  
H Nmr ◽  
High Yields ◽  
C Nmr

Abstract A direct one pot, three-component nitro-Mannich reaction of a nonenolizable aldehyde, aniline or one of its ring-substituted derivatives and nitromethane was carried out on silica gel surface. The products of the reaction, 2-aminonitroethane, were obtained in high yields. IR, 1H NMR, 13C NMR spectra and elemental analysis confirmed the structures of the products.

Evidence for stereoregulations in the polymerisation of phenylsilane by bis (indenyl)dimethylzirconium complexes

1990 ◽  
Vol 68 (9) ◽  
pp. 1638-1640 ◽  
Author(s):  
F. Gauvin ◽  
J. F. Harrod
Keyword(s):  
Molecular Weight ◽  
Nmr Spectra ◽  
Low Molecular Weight ◽  
H Nmr ◽  
Zirconium Complexes

Bis(indenyl)dimethylzirconocene, 1, and [1,2-bis(indenyl)ethane]dimethylzirconocene, 2, both catalyze the dehydropolymerization of phenylsilane to a mixture of low molecular weight cyclic oligosilanes (PhSiH)n (n = 6–9). The limited number of sharp resonances in the 29Si and 1H NMR spectra of the polymer produced with 2 as catalyst indicates that the catalyst exerts a significant stereoregulating influence on the polymerization. Keywords: polysilanes, catalytic dehydrocoupling, stereoregulation, bis(indenyl)zirconium complexes.

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