Unintended products

The hazardous materials used in the process may be raw materials, intermediates, products, by-products, cleaning materials, decomposition, or unintended products. 

Petrochemical and chemical processes may contain additional processes that need to be evaluated as applicable on raw materials, catalysts, intermediates, products, by-products, unintended products, solvents, inhibitors, quenchers, decomposition products, and cleaning products, such as ... 

In many reactions the actual yield almost exactly equals the theoretical yield, and the reactions are said to be quantitative. Such reactions can be used in quantitative chemical analyses. In other reactions the actual yield is less than the theoretical yield, and the percent yield is less than 100%. The reduced yield may occur for a variety of reasons. (1) The product of a reaction rarely appears in a pure form, and some product may be lost during the necessary purification steps, which reduces the yield. (2) In many cases the reactants may participate in reactions other than the one of central interest. These are called side reactions, and the unintended products are called by-products. To the extent that side reactions occur, the yield of the main product is reduced. (3) If a reverse reaction occurs, some of the expected product may react to re-form the reactants, and again the yield is less than expected. 

Decomposition Hazards. The main causes of unintended decompositions of organic peroxides are heat energy from heating sources and mechanical shock, eg, impact or friction. In addition, certain contaminants, ie, metal salts, amines, acids, and bases, initiate or accelerate organic peroxide decompositions at temperatures at which the peroxide is normally stable. These reactions also Hberate heat, thus further accelerating the decomposition. Commercial products often contain diluents that desensitize neat peroxides to these hazards. Commercial organic peroxide decompositions are low order deflagrations rather than detonations (279). 

Adverse reaction means a response to a medicinal product which is noxious and unintended and which occurs at doses normaily used in man for the prophyiaxis, diagnosis or therapy of disease or for the restoration, correction or modification of physioiogical function. 

Experience with chlorofluorocarbons (CFCs), insecticides such as DDT, herbicides and fertilizers has taught us that extended stability of these products may lead to unexpected harmfiil results. An important challenge will be to develop novel products that have a limited stable life and then decompose so that they do not persist in this environment. Examples are the development of plastic packages that decompose and degrade with time and of agricultural chemicals that do not harm unintended targets and are not overly persistent. 

Any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. 

PBDEs are a group of chemicals widely used as fire retardants in various commercial products. They have also been found in almost all environmental media around e-waste recycling sites, presumably due to unintended releases during primitive recycling operations. Herein a summary of the levels of PBDEs around e-waste recycling and reference sites is presented. 

Finally, a particularly interesting ongoing challenge will be to understand the potential for do-it-yourself immune stimulation to have unintended consequences. There are now many herbal supplements, functional foods and other over-the-counter products that promise to boost the immune response and most are considered to be safe for use by the general public. Although there is limited published evidence of adverse immune system effects of these materials, some have been associated with autoimmunity [95,96], See chapter 11 for a detailed discussion of the beneficial and potential adverse effects of nutraceuticals and functional foods. 

The main business of most chemical companies is to manufacture products by means of controlled chemical reactions. The reactivity that makes chemicals useful can also make them hazardous. Chemical reactions are usually carried out without mishap, but sometimes they get out of control because of problems such as the wrong or contaminated raw material being used, changed operating conditions, unanticipated time delays, failed equipment, incompatible materials of construction, or loss of temperature control. Such mishaps can be worse if the chemistiy under both normal and abnormal conditions is not fully understood. Therefore, it is essential that chemical process designers and operators understand the nature of the reactive materials andchemistry involved and what it takes to control intended reactions and avoid unintended reactions throughout the entire life cycle of a process facility. 

Understand the hazards of the products of both intended and unintended reactions. 

Adverse drug reaction (ADR) In the preapproval clinical experience with a new medicinal product or its new usages, particularly as the therapeutic dose(s) may not be established all noxious and unintended responses to a medicinal product related to any dose should be considered adverse drug reactions. ... 

Accidental incidents involving new types of emergencies began to surface in the 1940s. They were linked with the behavior of certain chemical products collectively called hazardous chemicals (or hazardous materials) whenever they are misused or involved in unintended mishaps and fires. 

Starting materials can be defined as the raw materials that form the basis of a chemical reaction as a part of the synthesis of an intermediate in the production of a drug substance. Catalysts typically include any material added to a mixture to accelerate, control, or otherwise modify a chemical reaction. Intermediates are those products of a synthesis scheme that will undergo further reaction. By-products are the side-products of a chemical reaction, and may include conjugates, dimers, enantiomers, unintended salts or free-bases, over-substitution, others. These types of impurities are usually considered to be process impurities and are not expected to increase in concentration over time. 

---