Radiochemical Investigation of Polymer Unsaturation. Reaction of Butyl Rubber with Radiochlorine

1963 ◽  
Vol 36 (4) ◽  
pp. 1071-1080
Author(s):  
I. C. McNeill
Keyword(s):  
Free Radical ◽  
Double Bond ◽  
Side Effects ◽  
Butyl Rubber ◽  
Small Scale ◽  
Substitution Process ◽  
Vacuum Line ◽  
Iodine Chloride

Abstract The reaction between chlorine and butyl rubber is of interest for two reasons: because of the industrial importance of the reaction the mechanism of which has not been fully understood, and because of the possibility of using it as a method for the determination of unsaturation. By the use of (36Cl)-chlorine, it has been possible to study the reaction on a conveniently small scale, the radiochlorine being manipulated quantitatively by a vacuum line technique. It has been shown that the reaction with chlorine is freer from side effects than the iodine chloride reaction. Two atoms of chlorine are incorporated in the polymer for each double bond originally present. These are incorporated not by addition but by a substitution process which is probably not free-radical in nature. A mechanism is proposed for the reaction. Radiochlorine is demonstrated to be potentially a useful reagent for investigating very low unsaturations in polymers.

Sulfur Bond in Vulcanizates Implications of Halogen Reactions

1947 ◽  
Vol 20 (3) ◽  
pp. 627-648
Author(s):  
S. R. Olsen ◽  
C. M. Hull ◽  
Wesley G. France
Keyword(s):  
Double Bond ◽  
Carbon Tetrachloride ◽  
Sulfur Atom ◽  
Side Reactions ◽  
Double Bonds ◽  
Vulcanized Rubber ◽  
Iodine Chloride ◽  
Allyl Sulfide ◽  
Sulfur Bond

Abstract 1. When iodine chloride is used for the determination of double bonds in sulfur-vulcanized rubber or GR-S, it undergoes side reactions induced by combined sulfur. 2. Bromine in carbon tetrachloride is believed to give a satisfactory measure of the double bonds in a rubber-sulfur vulcanizate dissolved in dichlorobenzene-chloroform mixture. 3. The relation of one double bond consumed per sulfur atom combined in the rubber-sulfur type vulcanizate was confirmed. 4. Organic accelerators (in the absence of metal activators) catalyze the combination of sulfur without altering the ratio of one double bond loss per sulfur atom combined. 5. The introduction of a metal oxide or soap, such as zinc, causes a different type of vulcanization, which results in less than one double bond consumed per sulfur atom combined. 6. The reactions of propyl sulfide, dodecyl sulfide, propyl disulfide, allyl sulfide, methallyl sulfide, and butylmethallyl sulfide with iodine chloride and with bromine, respectively, are described. 7. The behavior of rubber-sulfur vulcanizates resembles that of butylmethallyl sulfide in reactions with iodine chloride and bromine, respectively; this suggests an alkyl-allyl type sulfur bond. 8. The theory of vulcanization proposed by Armstrong, Little, and Doak, based on the α-methylenic concept of Farmer, is supported by the findings of this investigation.

Determination of Double Bonds in Ethylene Propylene Terpolymer Rubbers

1967 ◽  
Vol 40 (3) ◽  
pp. 936-946 ◽  
Author(s):  
R. Hank
Keyword(s):  
Double Bond ◽  
Conjugated Dienes ◽  
Butyl Rubber ◽  
Double Bonds ◽  
Ethylene Propylene ◽  
Qualitative And Quantitative ◽  
Considerable Success

Abstract Developments in the field of sulfur vulcanized unsaturated ethylene propylene terpolymer rubbers, also known as EPT rubbers, have progressed rapidly in recent years. Considerable success has been achieved in producing EPT rubbers from ethylene, propylene, and various dienes. Initial difficulties, involving introduction of double bonds into already known ethylene propylene copolymers, were soon overcome when it became clear that it was not the then commonly conjugated dienes such as butadiene and isoprene, but rather nonconjugated dienes, which were required for successful terpolymerization with ethylene and propylene, according to the Ziegler process. As with butyl rubber, it is sufficient, for vulcanization purposes, to incorporate one or two mole per cent of such dienes into the terpolymer. It is especially important, not only for polymerization, but also for rubber processing, to know the type and amount of unsaturation. In this article we wish first of all to report on double bond determinations in general and then, in particular, on qualitative and quantitative dicyclopentadiene determinations in ethylene propylene terpolymers. It is especially important, not only for polymerization, but also for rubber processing, to know the type and amount of unsaturation. In this article we wish first of all to report on double bond determinations in general and then, in particular, on qualitative and quantitative dicyclopentadiene determinations in ethylene propylene terpolymers.

THE THYMOLYTIC ACTIVITY OF 6- AND 9-HALOCORTICOIDS AND RELATED STEROIDS

1965 ◽  
Vol 49 (2) ◽  
pp. 262-270 ◽  
Author(s):  
Ralph I. Dorfman ◽  
P. G. Holton ◽  
Fred A. Kind
Keyword(s):  
Double Bond ◽  
Subcutaneous Injection ◽  
Fluocinolone Acetonide ◽  
Relative Potency ◽  
Subcutaneous Route ◽  
Adrenalectomized Rats

ABSTRACT Adrenalectomized rats were used for the determination of the relative potency of various 6- and 9-halo substituted corticoids administered subcutaneously or by gavage using thymus weightas the endpoint. By subcutaneous injection, fluocinolone acetonide was the most active corticoid at 700 times that of cortisol. This compound was also the most active corticoid by the gavage route and was judged to be 570 times as active as the standard cortisol. The introduction of the 16,17-acetonide and 16,17-acetone 21-acetate groups into 17α,21-dihydroxy-9α,11β-dichloropregna-1,4-diene-3,20-dione increased the activity by a factor of 42 and 100, respectively. The introduction of the δ1 double bond into 6α-fluoroprogesterone 16,17-acetonide caused an increase of 10-fold in thymolytic activity assessed by the subcutaneous route

Gradient-Enhanced Inverse-Detected NMR Techniquesfor Determination of 1H-15N Coupling Constants in 2,2-Dimethylpenta-3,4-dienal Derivatives

1997 ◽  
Vol 62 (11) ◽  
pp. 1747-1753 ◽  
Author(s):  
Radek Marek
Keyword(s):  
Double Bond ◽  
Chemical Shifts ◽  
Multiple Bond ◽  
Coupling Constants ◽  
Single Quantum ◽  
Nmr Techniques ◽  
Phase Sensitive ◽  
Heteronuclear Coupling

Determination of 15N chemical shifts and heteronuclear coupling constants of substituted 2,2-dimethylpenta-3,4-dienal hydrazones is presented. The chemical shifts were determined by gradient-enhanced inverse-detected NMR techniques and 1H-15N coupling constants were extracted from phase-sensitive gradient-enhanced single-quantum multiple bond correlation experiments. Stereospecific behaviour of the coupling constants 2J(1H,15N) and 1J(1H,13C) has been used to determine the configuration on a C=N double bond. The above-mentioned compounds exist predominantly as E isomers in deuteriochloroform.

A Review on Analytical Method for Determination of Lamotrigine in Bulk and Pharmaceutical Dosage Form

2021 ◽  
pp. 229-234
Author(s):  
Rutuja S Nalkar ◽  
Suhas S Siddheshwar ◽  
Mahesh H Kolhe
Keyword(s):  
Side Effects ◽  
Blood Cells ◽  
Anticonvulsant Drug ◽  
Mood Stabilizer ◽  
Stevens Johnson Syndrome ◽  
Partial Seizures ◽  
Pharmaceutical Dosage Form ◽  
Johnson Syndrome ◽  
Clonic Seizures

Lamotrigine is an anticonvulsant drug used in the treatment of epilepsy & bipolar disorder/major affective disorder (manic depression). Lamotrigine is and antiepileptic drug of phenyltriazine class. For epilepsy it is used to treat the partial seizures, primary and secondary tonic-clonic seizures, and seizures associated with the Lennox-Gastuat syndrome and are chemically unrelated to the other anticonvulsants. Lamotrigine is a phenyltriazine that has comparatively few side-effects and it does not requires blood monitoring/observance in monotherapy. It additionally acts as a mood stabilizer. Common side-effects of lamotrigine include, nausea, sleepiness, headache, vomiting, trouble/bother with co-ordination and rash. Serious side-effects include in, lack of red blood cells, accumulated in risk of suicide, Stevens-Johnson syndrome and allergy. It issues that use of lamotrigine throughout pregnancy or breastfeeding it’s going to lead/result in harm/damage.

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