Killing reactions

Our main objective was the identification and determination of the Al-C bonds. This we did by killing the reaction mixtures with tritiated water and then counting the tritium content of the polymers. In our systems this killing reaction forms one tritium-carbon bond (Equation (iv)). 

Monomers devoid of polar groups generally undergo anionic polymerization in a predictable manner. With polar monomers sometimes side reactions occur during the process transfer reactions in the case of acrylonitrile, or propylene oxide, and even more so with alkylacrylates deactivations (or "killing") reactions in the case of halogen substituted styrene or dienes. 

Surprisingly, the alkoxy group (and not the proton) from the methanol was found in the killed polymer. This suggests a polarity in the site-polymer bond which is opposite to that generally imagined. The polymer would be more positive than the site. Yermakov and Zakharov (72, 73) proposed that the polymer may actually grow from an oxide rather than from the Cr. Before any hard conclusions can be drawn, however, more must be known about the kill reaction itself, i.e., whether it really is the true kill mechanism and not just a side reaction connected with oxidation of Cr(II) by methanol, and whether it really is quantitative. 

The kinetics of the microbiological kill reaction is more favorable for bromine. Thus bromine tends to kill microbes more quickly, and for any disinfection time period it will achieve a higher magnitude of kill. This can be important for cooling systems with short disinfection contact times, e.g., once-through systems. 

The importance of the plasma membrane as the site of action of im-munologically mediated cytotoxicity reactions involving humoral or cellular factors has recently become evident. In this regard, several studies have shown that humoral immune killing reactions involve a complex series of biochemical interactions between the attacker moieties and the cell surface membrane.One approach in studying and elucidating such interactions could therefore focus on the effects of the immune attack processes on the synthesis and/or turnover of cell surface macromolecules known to be structural and functional components of the plasma membrane (e.g., proteins and lipids). 

The radical oxidation and radical reduction are chain killing reactions, which limits the molecular weights of polymers prepared by ATRP. As with reduction, the molecular weights that can be reached in systems where radical oxidation is possible are determined by the ratio of the rates of propagation and oxidation, which is inversely proportional to the amount of oxidant (eqn (8.40)). 

Using the microwave Just decreased the reaction time to 3-30minutes. The dudes in the article used a household, 500W Brazilian microwave (Yikesl). They cut a whole in the top of the microwave to allow the condenser apparatus to pass through the oven. They then killed themselves most likely. But not before they were able to scratch down this procedure as they slowly burned to death ... 

Chain reactions do not go on forever. The fog may clear and the improved visibility ends the succession of accidents. Neutron-scavenging control rods may be inserted to shut down a nuclear reactor. The chemical reactions which terminate polymer chain reactions are also an important part of the polymerization mechanism. Killing off the reactive intermediate that keeps the chain going is the essence of these termination reactions. Some unusual polymers can be formed without this termination these are called living polymers. 

The compound R X is a chain-transfer agent, with X usually H or Cl. The net effect of chain transfer is to kill a growing chain and start a new one in its place, thus shortening the chains. Mercaptan chain-transfer agents ate often used to limit molecular weight, but under appropriate conditions, almost anything in the reaction mass (solvent, dead polymer, initiator) can act as a chain-transfer agent to a certain extent. 

Germicidal Properties. The germicidal activity of aqueous chlorine is attributed primarily to HOCl. Although the detailed mechanism by which HOCl kills bacteria and other microorganisms has not been estabUshed, sufficient experimental evidence has been obtained to suggest strongly that the mode of action involves penetration of the cell wall followed by reaction with the enzymatic system. The efficiency of destmction is affected by temperature, time of contact, pH, and type and concentration of organisms (177). 

Available Chlorine Test. The chlorine germicidal equivalent concentration test is a practical-type test. It is called a capacity test. Under practical conditions of use, a container of disinfectant might receive many soiled, contaminated instniments or other items to be disinfected. Eventually, the capacity of the disinfectant to serve its function would be overloaded due to reaction with the accumulated organic matter and organisms. The chlorine germicidal equivalent concentration test compares the load of a culture of bacteria that a concentration of a disinfectant will absorb and still kill bacteria, as compared to standard concentrations of sodium hypochlorite tested similarly. In the test, 10 successive additions of the test culture are added to each of 3 concentrations of the hypochlorite. One min after each addition a sample is transferred to the subculture medium and the next addition is made 1.5 min after the previous one. The disinfectant is then evaluated in a manner similar to the phenol coefficient test. For equivalence, the disinfectant must yield the same number of negative tubes as one of the chlorine standards. 

As the polymer molecules form and dissociate from the catalyst, they remain ia solution. The viscosity of the solution increases with increasing polymer concentration. The practical upper limit of solution viscosity is dictated by considerations of heat transfer, mass transfer, and fluid flow. At a mbber soflds concentration of 8—10%, a further increase in the solution viscosity becomes impractical, and the polymerisation is stopped hy killing the catalyst. This is usually done by vigorously stirring the solution with water. If this is not done quickly, the unkilled catalyst continues to react, leading to uncontrolled side reactions, resulting in an increase in Mooney viscosity called Mooney Jumping. 

When the steam was shut off and, 15 minutes later, the agitator was switched off, heat transferred from the hot wall above the liquid level to the top part of the liquid, which became hot enough for a runaway reaction to start. This resulted in a release of TCDD (dioxin), which killed a number of nearby animals, caused dermatitis (chloracne) in about 250 people, damaged vegetation near the site, and required the evacuation of about 600 people (Kletz 1994). 

Consider the following example in which the worker risk from a catastrophic accident has been calculated to be 2 X 10 fatalities per year. It is possible to interpret this number in many ways, but one of the most common ways is the following there is one chance in 5000 per year that a worker will be fatally injured at the plant. However, you should be cautious when interpreting single risk estimates that are the sums of products of frequency and consequence of many accidents. The way you believe (and act) may be affected by the frequency/consequence profile that the number represents (see Sections 3.2.4 and 4.2.5.) That is, your reaction to an accident that occurs once every 100 years and kills 1 person (Risk = 10 fatalities per year) and your reaction to an accident that occurs once every 10,000 years and kills 100 people (Risk = 10 fatalities per year) are likely to be very different. 

Primary irritants cause inflammation. Inflammation is one of the body s defence mechanisms. It is the reaction of a tissue to harm which is insufficient to kill the tissue and is typified by... 

A reaction vessel explosion at BASF s resins plant in Cincinnati (July 19, 1990) killed one and injured 71. The BASF facility manufactures acrylic, alkyd, epoxy, and phenol-formaldehyde resins used as can and paper-cup liner coatings. The explosion occurred when a flammable solvent used to clean a reaction vessel vented into the plant and ignited. The cleaning solvent that was not properly vented to a condenser and separator, blew a pressure seal, and fdled the 80-year-old building with a white vapor cloud. 

The use of an unnecessarily hot heating medium led to the runaway reaction at Seveso, Italy, in 1976, which caused a fallout of dioxin over the sun ounding countryside, making it unfit for habitation. Although no one was killed, it became one of the best-known chemical accidents, exceeded only by Bhopal, and had far-reaching effects on the laws of many countries. 

The phospholipid breakdown product of this reaction, lysoleeithin, acts as a detergent and dissolves the membranes of red blood cells, causing them to rupture. Indian cobras kill several thousand people each year. 

The conditions which affect the type of reaction are bath temperature and the composition of iron or steel which is being coated. At 480-520°C the reaction between iron and zinc can be linear with time so that the thickness of the alloy layers will increase in direct proportion to the immersion time and the reaction will continue to be relatively rapid. With some steels (e.g. some silicon-killed steels), the reaction can be linear at the normal galvanising temperature of about 450 C. 

The hypochlorous acid, HCIO, formed by this reaction is a powerful oxidizing agent (E a = +1.630 V) it kills bacteria, apparently by destroying certain enzymes essential to their metabolism. The taste and odor that we associate with chlorinated water are actually due to compounds such as CH3NHC1, produced by the action of hypochlorous acid on bacteria. 

Acetanilide has been used medicinally as a pain-killing zene, which is chlorinated as a first step. Reaction of remedy. chlorobenzene with base gives phenol ... 

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