Synthesis of N-hydroxymethylacrylamide in an aqueous solution

1986 ◽  
Vol 51 (8) ◽  
pp. 1656-1664 ◽  
Author(s):  
Alois Matějíček ◽  
Jaroslav Černý

The paper deals with a reaction between acrylamide and formaldehyde leading to the synthesis of N-hydroxymethylacrylamide. The reaction was carried out in the temperature range 303.2 to 333.2 K, pH 9.2-10.35, at the methanol concentration 0-6.5239 mol l-1 at the constant molar ratio of acrylamide to formaldehyde 1 : 1. The time dependence of the loss of formaldehyde in the reaction mixture was approximated by an empirical relation (cF)0 - cF = t/(A + Bt), which was used in the determination of the rate constants for a reaction leading to the synthesis of N-hydroxymethylacrylamide and for the reversible reaction, and of the equilibrium constant of the reaction. The measurements and calculations showed that the optimal conditions for the synthesis of N-hydroxymethylacrylamide were 313.2 K, methanol concentration 1.5 mol l-1 and pH 9.8-10.1.

1981 ◽  
Vol 34 (7) ◽  
pp. 1433 ◽  
Author(s):  
JE Packer ◽  
J Monig ◽  
BC Dobson

Some rate constants for the reduction of para-substituted benzenediazonium ions by the radicals eaq-, ·CH2OH, (CH3)2·COH and some semiquinone radical anions have been measured. The substituent group has no effect on the rates with eaq-, but as the reduction potential of the reducing radical becomes more positive, the substituent effect increases, electron-withdrawing groups enhancing the rates. No free halide is formed on reduction of p-BrC6H4N2+ or p-IC6H4N2+ by eaq- or ·CH2OH.


2007 ◽  
Vol 52 (3) ◽  
pp. 762-765 ◽  
Author(s):  
Bintao Liu ◽  
Hua Chen ◽  
Yanpeng Mao ◽  
Wende Xiao

1983 ◽  
Vol 61 (1) ◽  
pp. 171-178 ◽  
Author(s):  
J. Peter Guthrie ◽  
Brian A. Dawson

In aqueous sodium hydroxide solutions at 25 °C, 3-methyl-2-butenal, 1c, undergoes retroaldol cleavage to acetone and acetaldehyde. The kinetics of the retroaldol reaction were followed spectrophotometrically at 242 nm and showed simple first order behavior. When 3-methyl-3-hydroxybutanal, 2c, was added to aqueous sodium hydroxide solutions at 25 °C, there was an initial increase in absorbance at 242 nm, attributed to formation of 1c, followed by a 20-fold slower decrease; the rate of the slow decrease matches the rate of disappearance of 1c under the same conditions. Analysis of the kinetics allows determination of the three rate constants needed to describe the system: khyd = 0.00342; kdehyd = 0.00832; kretro = 0.0564; all M−1 s−1. The equilibrium constant for enone hydration is 0.41. Rate constants for the analogous reactions for acrolein and crotonaldehyde could be obtained from the literature. There is a reasonable rate–equilibrium correlation for the retroaldol step. For the enone hydration step, rate and equilibrium constants respond differently to replacement of hydrogen by methyl. It is proposed that this results from release of strain after the rate-determining step by rotation about a single bond; this decrease in strain is reflected in the equilibrium constant but not in the rate constant.


2013 ◽  
Vol 35 (3) ◽  
pp. 186-195 ◽  
Author(s):  
Gracia Márquez ◽  
Eva M. Rodríguez ◽  
Fernando J. Beltrán ◽  
Pedro M. Álvarez

1988 ◽  
Vol 53 (5) ◽  
pp. 929-938
Author(s):  
František Skopal

The time dependence of the volume of solution of one reaction component injected continuously to the solution of the other reaction component is derived for the case that the injection is controlled by feedback to hold the absorbance of the reaction mixture constant. An experimental apparatus based on this principle has been set up and its function tested on two 2nd order reactions, whereby the theoretical relations derived for the determination of the rate constants have also been verified.


Author(s):  
Casey McCullough ◽  
Matthew Heywood ◽  
Hussein Samha

The effect of phospholipid, 1,2-Dipalmitoyl-sn-glycero-3-Phosphocholine (DPPC) on the spectroscopy of the cyanine dye, 1-ethyl-1’-octadecyl-2,2’-cyanine iodide (PIC-18), has been investigated using UV-Vis spectroscopy. Vesicles of DPPC containing PIC-18 in the molar ratio of 1:3 (dye/phospholipids) were prepared in aqueous solution. J-aggregates of PIC-18 were detected in the bilayer wall of the vesicles. When an aqueous solution of mixed PIC-18/DPPC vesicles is treated with excess DPPC vesicles that are prepared separately, the dye molecules in the mixed vesicles underwent a rapid (aggregate)n' n(monomer) equilibrium as the appearance of only one isosbestic point in the absorbance of the dye indicates. The equilibrium constant was calculated at room temperature (Keq = 6.7x10-2). An aggregation number of 4 was calculated for the dye in the bilayer vesicles.


2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Adrian Turtureanu

The paper presents the removal of cadmium by flotation from dilute aqueous solutions, at a laboratory scale, using an anionic collector (oleic acid). The optimum values of the main parameters influencing this process were determined: pH of Cd(II) solutions, molar ratio collector:Cd(II), air flow rate, flotation time and initial concentration of Cd(II). Using these optimal conditions, a very high removal degree of cadmium (over 99%) was obtained.


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