Nitroglycerine reduction

Exothermic oxidation—reduction reactions provide the energy released in both propellant burning and explosive detonation. The reactions are either internal oxidation—reductions, as in the decomposition of nitroglycerin and pentaerythritol tetranitrate, or reactions between discrete oxidizers and fuels in heterogeneous mixtures. 

Other P"Adrenoceptor Blocking Agents. Carteolol hydrochloride (Table 1) is also a Class II antiarrhythmic agent. In three separate studies in patients having angina pectoris, carteolol was considered effective as evidenced by a reduction in the frequency and severity of anginal episodes, reduction in the amount of nitroglycerin consumed, improvement of ECG parameters, or an increase in the duration of trea dmill exercise (42). 

Nitroglycerin (NG) production provides a good example of the reductions in inventory that can be achieved by redesign. It is made from glycerin and a mixture of concentrated nitric and sulfuric acids. The reaction is very exothermic if the heat is not removed by cooling and stirring, an uncontrollable reaction is followed by explosive decomposition of the NG. 

Gallwitz (Ref 16) reports the following data on the influence of the heat of explosion upon the bore wear. With a nitroglycerine powder containing no solvent and giving a heat of explosion of 950 kcal, the barrel stands up to 1700 rounds while with a similar powder giving a heat of explosion of 820 kcal, it withstands 3500 rounds. The reduction of the calorific value of the powder by 130 kcal therefore doubles the useful life of the barrel... 

Further reduction of the calorific value of nitroglycerine powder proved to be impossible. But by using nitrodiglycol instead of nitroglycerine, a powder was obtained with a heat of explosion of 690 kcal, which prolonged the life of the barrel considerably, i.e. to 15,000-17,000... 

For variant angina, reduction in symptoms and nitroglycerin consumption as documented by a patient diary can assist the interpretation of objective data obtained from ambulatory ECG recordings. Evidence of efficacy includes the reduction of ischemic events, both ST-segment depression and elevation. Additional evidence is a reduced number of attacks of angina requiring hospitalization, and the absence of MI and sudden death. 

NO is recognized as a mediator of bone cell metabolism, where it regulates osteoblast and osteoclast activity [141-143]. Osteoporosis, which frequently occurs in postmenopausal women, is a systemic skeletal disease associated with abnormal bone resorption. Addition of NO or NO donors to osteoclasts in vitro results in a reduction in bone resorption, whereas NO synthase inhibitors increase bone resorption, both in vitro and in vivo. Further research has shown that NO reduces bone resorption, via inhibition of the cysteine protease cathepsin K, which is believed to be a key protease in bone resorption. Most of the NO donors, i.e., nitroglycerin, 3-... 

Tolerance to nitrates is defined as the reduction in hemodynamic effect or the requirement for higher doses to achieve a persistent effect with continuous use in the face of constant plasma concentrations [15]. Nitrate tolerance was first described for nitroglycerin in 1888 [36] it occurs with all organic nitrates, albeit to different extents. For reasons that are not understood, PETN appears to be the least susceptible to the development of tolerance. No, or much less, tolerance is observed with nitrite esters, such as amyl nitrite [37], molsidomine, and sodium nitroprusside. Earlier investigations suggested that a depletion of intracellular thiols is involved in tolerance development [17], but this has not been substantiated in later studies [38, 39]. As with organic nitrate bioactivation, the precise mechanism(s) involved in nitrate tolerance remain(s) unknown, but it is likely to be complex and multifactorial. Two principal... 

According to Laplace s law, a reduction in ventricular pressure and heart size results in a decrease in the myocardial wall tension that is required to develop a given intraventricular pressure and therefore decreases oxygen requirement. Since blood flow to the subendocardium occurs primarily in diastole, the reduction in left ventricular end diastolic pressure induced by nitroglycerin reduces extravascular compression around the subendocardial vessels and favors redistribution of... 

D. Nitroglycerin can reduce preload, which in turn reduces wall tension and increases subendocardial blood flow. Nitroglycerin also reduces afterload, but this is a small effect compared to the reduction in preload. Its effects on heart rate and contractility are minimal, and if anything reflex tachycardia and increase in contractility would be detrimental effects of too much nitroglycerin. 

Angina-. Reduction in nitroglycerin usage frequency, severity, onset, and duration of angina pain heart rate... 

The difficulties in obtaining a unifoim paste were completely eliminated when nitroglycerine or dinitrodiethyleneglycol was used in the form of an aqueous emulsion for mixing with nitrocellulose under water (see pp. 647 and 661). Nitrocellulose adsorbs nitroglycerine very uniformly from an aqueous medium, so the paste thus obtained may be utilized for further processing immediately after the removal of water. This is best achieved in centrifuges. They reduce the water content to about 30%, while for further reduction (to 8-10%) screw presses are preferable. 

In certain cases the hydrolysis process does not result in the formation of the initial alcohol at all, but a series of other compounds is obtained, by a reaction mechanism which is often unknown. As an example, the hydrolytic reaction of nitroglycerine performed in an aqueous or alcoholic solution of sodium or potassium hydroxide can be quoted. Oxidation and reduction processes take place simultaneously to form organic acids as well as nitrates and nitrites. After Hay [32] the course of the reaction can be summarized by the eqn. (2) ... 

The oldest and most popular method is reductive hydrolysis by means of alkaline sulphides or hydrosulphides, for instance sodium or ammonium sulphide or the corresponding hydrosulphide, as discussed above in connection with the question of hydrolysis (pp. 9-10). According to Oehman et al. [103] acid hydrolysis of nitroglycerine follows a course similar to that of eqn. (58). Hydrolysis with sulphuric acid (even in the presence of nitric acid) may lead to a transesterification and formation of sulphuric acid esters [104]. 

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