Preparation of cis-crotonyl chloride

1968 ◽  
Vol 46 (3) ◽  
pp. 466-468 ◽  
Author(s):  
M. B. Hocking
Keyword(s):  
Trans Isomer ◽  
Acid Chloride ◽  
Boiling Point ◽  
Free Acid ◽  
Isomer Separation ◽  
Crotonyl Chloride ◽  
Chloride Contaminated

Published methods for the preparation of cis-crotonyl chloride were found to give a product contaminated with appreciable proportions of the trans isomer. Separation of these two isomers was found to be impossible because of the small boiling point difference and the readiness with which the cis acid chloride isomerizes to the trans. Herein are outlined the precautions necessary to obtain pure cis-crotonyl chloride contaminated only with the free acid, from which it is readily separated by cold distillation.

Phosphonolipids. XV. Synthesis of a dihydroceramide aminoethylphosphonate

1968 ◽  
Vol 46 (3) ◽  
pp. 525-532 ◽  
Author(s):  
Erich Baer ◽  
Bimal C. Pal
Keyword(s):  
Chemical Synthesis ◽  
Acid Chloride ◽  
Phosphonic Acid ◽  
Steam Distillation ◽  
Free Acid ◽  
Reaction Products ◽  
New Class ◽  
Naturally Occurring ◽  
Benzoyl Group ◽  
Complex Lipids

The first chemical synthesis of a dihydroceramide aminoethylphosphonate is described. It is a saturated representative of a new class of recently discovered, naturally occurring complex lipids derived from phosphonic acid. The compound, viz. erythro-N-palmitoyl-DL-dihydrosphingosyl-1-(2-aminoethyl)-phosphonate, was obtained by two procedures: phosphonylation of erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosine with (2-N,N-dibenzylammoethyl)phosphonic acid chloride (hydrochloride) and triethylamine, or with (2-phthalimidoethyl)phosphonic acid monochloride and triethylamine, and freeing the reaction products of both procedures, viz. erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosyl-1-(2-N,N-dibenzylaminoethyl)phosphonate and erythro-N-palmitoyl-3-O-benzoyl-DL-dihydrosphingosyl-1-(2-phthalimidoethyl)phosphonate, from their protective benzyl or phthaloyl group by hydrogenolysis or hydrazinolysis, respectively, followed in both cases by removal of the benzoyl group by saponification.The (2-N,N-dibenzylaminoethyl)phosphonic acid was obtained by treating (2-bromoethyl)phosphonic acid with N,N-dibenzylamine and converting the reaction product, viz. the dibenzylammonium salt of (2-N,N-dibenzylaminoethyl)phosphonic acid, into the free acid by steam distillation.

Calcium ion imaging in plant cells

1993 ◽  
Vol 51 ◽  
pp. 132-133
Author(s):  
Peter K. Hepler ◽  
Dale A. Callaham
Keyword(s):  
Plant Cell Wall ◽  
Cytoplasmic Membrane ◽  
Fluorescent Dyes ◽  
Free Acid ◽  
Methyl Esters ◽  
Free Calcium ◽  
Local Concentration ◽  
Ion Imaging ◽  
Membrane Compartments ◽  
Free Acid Form

Calcium ions (Ca) participate in many signal transduction processes, and for that reason it is important to determine where these ions are located within the living cell, and when and to what extent they change their local concentration. Of the different Ca-specific indicators, the fluorescent dyes, developed by Grynkiewicz et al. (1), have proved most efficacious, however, their use on plants has met with several problems (2). First, the dyes as acetoxy-methyl esters are often cleaved by extracellular esterases in the plant cell wall, and thus they do not enter the cell. Second, if the dye crosses the plasma membrane it may continue into non-cytoplasmic membrane compartments. Third, even if cleaved by esterases in the cytoplasm, or introduced as the free acid into the cytoplasmic compartment, the dyes often become quickly sequestered into vacuoles and organelles, or extruded from the cell. Finally, the free acid form of the dye readily complexes with proteins reducing its ability to detect free calcium. All these problems lead to an erroneous measurement of calcium (2).

Inhibition of Radical-Initiated Vinyl Acetate Polymerisation by Tobacco Smoke Fractions

1974 ◽  
Vol 7 (5) ◽  
Author(s):  
M.A. Nisbet ◽  
S. Schmeller
Keyword(s):  
Benzoyl Peroxide ◽  
Vinyl Acetate ◽  
Tobacco Smoke ◽  
Boiling Point ◽  
Water Bath ◽  
Measuring Time ◽  
Time Required

AbstractBoth the vapour and particulate phases of tobacco smoke have been shown to retard benzoyI-peroxide-initiated polymerisation of vinyl acetate by interception of the radicals involved in the polymerisation process. The extent of inhibition of polymerisation by test compounds is estimated by measuring time taken for a mixture of monomer and benzoyl peroxide, immersed in a water-bath at 70°C, to reach a spontaneous boil and comparing it with the time required for a similar mixture with added retarder to reach boiling point. Units are expressed as minutes of inhibition per part per million of inhibitor × 10

HASTELLOY ALLOY D

Alloy Digest ◽  
1956 ◽  
Vol 5 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Physical Properties ◽  
Tensile Properties ◽  
Boiling Point ◽  
Cast Alloy ◽  
Heat Treating

Abstract HASTELLOY ALLOY-D is a cast alloy composed primarily of nickel and silicon, and is exceptionally resistant to sulfuric acid of all concentrations even up to the boiling point. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-29. Producer or source: Haynes Stellite Company.

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