Novel Conversion ofN,N-Dimethylformamide Dimethyl Acetal to Tetramethylammonium Salts by Its Reaction with 5-Methyl-4-Isoxazolecarboxylic Acid Derivatives

1991 ◽  
Vol 20 (1) ◽  
pp. 41-42 ◽  
Author(s):  
Baldev Singh ◽  
Allan G. Hlavac
Keyword(s):  
Dimethyl Acetal ◽  
Tetramethylammonium Salts

Conversion of fructose into methyl lactate over SnO2/Al2O3 catalystin flow regime

2020 ◽  
pp. 43-47
Author(s):  
S.V. Prudius ◽  
◽  
N.L. Hes ◽  
A.M. Mylin ◽  
V.V. Brei ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Practical Interest ◽  
Dimethyl Acetal ◽  
Racemic Mixture ◽  
Process Conditions ◽  
Impregnation Method ◽  
Aqueous Methanol ◽  
Methyl Lactate ◽  
Al2o3 Catalyst ◽  
Target Reaction

In recent years, numerous researchers have focused on the development of catalytic methods for processing of biomass-derived sugars into alkyl lactates, which are widely used as non-toxic solvents and are the starting material for obtaining monomeric lactide. In this work, the transformation of fructose into methyl lactate on Sn-containing catalyst in the flow reactor that may be of practical interest was studied. The supported Sn-containing catalyst was ob-tained by a simple impregnation method of granular γ-Al2O3. The catalytic ex-periments were performed in a flow reactor at temperatures of 160-190 °C and pressure of 3.0 MPa. The 1.6-9.5 wt.% fructose solutions in 80% aqueous methanol were used as a reaction mixture. It was found that addition to a reac-tion mixture of 0.03 wt.% potassium carbonate leads to the increase in selec-tivity towards methyl lactate on 15% at 100% conversion of fructose. Prod-ucts of the target reaction С6Н12О6 + 2СН3ОН = 2С4Н8О3 + 2Н2О were ana-lyzed using 13C NMR method. The following process conditions for obtaining of 65 mol% methyl lactate yield at 100% fructose conversion were found: use of 4.8 wt.% fructose solution in 80% methanol, 180 °С, 3.0 МПа and a load on catalyst 1.5 mmol C6H12O6/mlcat/h at contact time of 11 minutes. The cata-lyst productivity is 2.0 mmol C4H8O3/mlcat/h and the by-productі are 1,3-dihydroxyacetone dimethyl acetal (20%) and 5-hydroxymethylfurfural (10%). It should be noted that a racemic mixture of L- and D-methyl lactates has been obtained by conversion of D-fructose on the SnO2/Al2O3 catalyst. The SnO2/Al2O3 catalyst was found to be stable for 6 h while maintaining full fruc-tose conversion at 55–70% methyl lactate selectivity. After regeneration the catalyst completely restores the initial activity.

Synthesis of 1,4‐Diaryl‐piperazine‐2,5‐diones: New Behavior of N,N‐Dimethylformamide Dimethyl Acetal (DMFDMA)

2008 ◽  
Vol 38 (3) ◽  
pp. 376-382 ◽  
Author(s):  
Fathi A. Abu‐Shanab ◽  
Ahmed Al‐Harrasi ◽  
Sayed A. S. Mousa
Keyword(s):  
Dimethyl Acetal

DMF Dimethyl Acetal as Carbon Source for α-Methylation of Ketones: A Hydrogenation–Hydrogenolysis Strategy of Enaminones

2015 ◽  
Vol 80 (9) ◽  
pp. 4722-4728 ◽  
Author(s):  
Ashwini Borah ◽  
Limi Goswami ◽  
Kashmiri Neog ◽  
Pranjal Gogoi
Keyword(s):  
Carbon Source ◽  
Dimethyl Acetal

Benzene-1,2-disulfonate dianion: another compound with meshed cogwheel substituents?

1996 ◽  
Vol 52 (3) ◽  
pp. 562-568 ◽  
Author(s):  
N. Nagel ◽  
P. Eller ◽  
H. Bock
Keyword(s):  
Crystal Structures ◽  
Disulfonic Acid ◽  
Conformational Isomerization ◽  
Tetramethylammonium Salts

Crystal structures of the dipotassium and potassium tetramethylammonium salts of benzene-1,2-disulfonic acid have been determined at 200 K and a PM3 enthalpy hypersurface for the substituent rotations of the free benzene-1,2-disulfonate dianion was calculated. The cogging of the two sulfonate groups as well as the possible pathways of conformational isomerization are discussed and compared with already investigated molecules containing adjacent threefold substituents.

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