Maximization of the Conversion to m-Toluenesulfonic Acid in Sulfuric Acid Sulfonation

1973 ◽  
Vol 12 (3) ◽  
pp. 295-300 ◽  
Author(s):  
Allen R. Broyles ◽  
Roger E. Eckert
Keyword(s):  
Sulfuric Acid ◽  
Toluenesulfonic Acid

Determination of para-toluenesulfonic acid and sulfuric acid in a mixture

1967 ◽  
Vol 1 (12) ◽  
pp. 705-706
Author(s):  
M. S. Goizman ◽  
A. A. Chemerisskaya
Keyword(s):  
Sulfuric Acid ◽  
Toluenesulfonic Acid

Synthesis of piperazine-2,5-diones related to bicyclomycin: 1,4-dibenzyl-3-hydroxy-3-[1-(2-methoxyethyl)ethenyl]piperazine-2,5-dione. 2. Route via cyclic intermediates

1983 ◽  
Vol 61 (7) ◽  
pp. 1397-1404 ◽  
Author(s):  
Peter Yates ◽  
John Harold Hoare
Keyword(s):  
Sulfuric Acid ◽  
Structural Features ◽  
Epoxide Ring ◽  
Reaction Sequence ◽  
Model Studies ◽  
Toluenesulfonic Acid

1,4-Dibenzyl-3-hydroxy-3-[1-(2-methoxyethyl)ethenyl]piperazine-2,5-dione (43), which incorporates several of the structural features of the antibiotic bieyclomycin, has been synthesized via a reaction sequence involving early construction of the piperazine-2,5-dione ring. In model studies 3-isopropylidenepiperazine-2,5-dione was di-N-benzylated and epoxidized to give 4,7-dibenzyl-2,2-dimethyl-1-oxa-4,7-diazaspiro[2.5]octane-5,8-dione (10). The opening of the epoxide ring of 10 by several reagents was investigated and it was found that treatment with magnesium isopropylcyclohexylamide (MICA) gives 1,4-dibenzyl-3-hydroxy-3-(1-methylethenyl)piperazine-2,5-dione (23). Treatment of ethyl 3-(2-methoxyethyl)-3-methyl-glycidate (28) with p-toluenesulfonic acid followed by hydrogenation and oxidation gives ethyl 5-methoxy-3-methyl-2-oxopentanoate, which on reaction with chloroacetamide and sulfuric acid followed by treatment of the resulting enamide with ammonia gives (Z)- and (E)-3-(4-methoxybut-2-ylidene)piperazine-2,5-dione. Di-N-benzylation of these followed by epoxidation gives (Z)- and (E)-4,7-dibenzyl-2-(2-methoxyethyl)-2-methyl-1-oxa-4,7-diazaspiro[2.5]octane-5,8-dione (41 and 42). Treatment of 41 with MICA converts it to compound 43. Chromatography of 43 on silica converts it in part to N-benzyl-N-(2-benzylamino-2-oxoethyl)-3-(2-methoxyethyl)-2-oxo-3-butenamide, which on treatment with MICA regenerates 43.

Some condensation products of ergoline - I Derivatives with ketones

1980 ◽  
Vol 45 (3) ◽  
pp. 755-760 ◽  
Author(s):  
Jiří Křepelka ◽  
Jiří Holubek ◽  
Miroslav Semonský
Keyword(s):  
Sulfuric Acid ◽  
Condensation Product ◽  
Condensation Products ◽  
Inhibiting Effect ◽  
Toluenesulfonic Acid ◽  
Cyclohexyl Ester ◽  
Acid Esterification ◽  
Derivatives Of

Monotopic bis-ergolin-2-yl derivatives of alkanes and cycloalkanes (I-VIII) were prepared on reaction of derivatives of ergoline-I (XI-XIV) with ketones in the presence of sulfuric acid or p-toluenesulfonic acid. Esterification of compound XV with cyclohexanol under catalysis with-p-toluenesulfonic acid gave condensation product IX after previous separation of cyclohexyl ester XVI. The condensation products did not exhibit prolactin inhibiting effect.

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

Physical, Chemical, and Crystallographic Characterization of Anodic Coatings on High Strength Aluminum Base Alloys

1976 ◽  
Vol 34 ◽  
pp. 636-637
Author(s):  
R. E. Herfert ◽  
N. T. McDevitt
Keyword(s):  
Sulfuric Acid ◽  
Salt Spray ◽  
High Strength ◽  
Environmental Stability ◽  
Anodic Films ◽  
Sodium Dichromate ◽  
Corrosion Resistant ◽  
Aerospace Applications ◽  
Bond Strengths ◽  
Adhesive Bonded Joints

Durability of adhesive bonded joints in moisture and salt spray environments is essential to USAF aircraft. Structural bonding technology for aerospace applications has depended for many years on the preparation of aluminum surfaces by a sulfuric acid/sodium dichromate (FPL etch) treatment. Recently, specific thin film anodizing techniques, phosphoric acid, and chromic acid anodizing have been developed which not only provide good initial bond strengths but vastly improved environmental durability. These thin anodic films are in contrast to the commonly used thick anodic films such as the sulfuric acid or "hard" sulfuric acid anodic films which are highly corrosion resistant in themselves, but which do not provide good initial bond strengths, particularly in low temperature peel.The objective of this study was to determine the characteristics of anodic films on aluminum alloys that make them corrosion resistant. The chemical composition, physical morphology and structure, and mechanical properties of the thin oxide films were to be defined and correlated with the environmental stability of these surfaces in humidity and salt spray. It is anticipated that anodic film characteristics and corrosion resistance will vary with the anodizing processing conditions.

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