Pt3 -- oozing on the muggy shore of the gulf coast [email protected]
--- Begin Message ---Hi Vincent and wonderful CSers, That was a good post Vincent, however some people may be getting confused about what we are talking about. Thats easy to do, what with all the fancy names and formulas.Let me try to clarify things a bit for listers. :-) How Organic Nomenclature Developed In the middle of the 19th century many organic compounds were unknown. Compounds were given names that illustrated their origins or properties. Some were named after friends or relatives and the chemists who discovered them. The name for *barbituric acid* (barbiturates) comes from a women named Barbara. Carboxylic acid (HCO2H) was obtained from distilling red ants. This acid was called *formic acid* from the Latin *formica* which means "ants". These kinds of names are called *trivial or common* names. All organic compounds today have their formal names that we try to use so everyone is talking about the same thing. But the trival names seem to keep popping up. :-) Faced with the specter of an unlimited number of organic compounds a standard system of nomenclature was developed. The first conference was held in Geneva,Switzerland and the system is sometimes refered to as the Geneva system. Actually the system is called *IUPAC nomenclature*. Thats International Union of Pure and Applied Chemistry,the organization responsible for maintaining order in the nomenclature system. A Word About Hydrocarbons Hydrocarbons are made from carbon (C) and hydrogen (H),put together they are called hydrocarbon (CH). All petroleum products are hydrocarbons, in different forms. Petroleum has been formed by the decay of plants and animals, mostly marine in origin. Crude petroleum (crude oil), is a complex mixture of aliphatic and aromatic compounds, including sulfer and nitrogen compounds. In fact over 500 compounds have been detected in a single sample of petroleum. Because of its complexity, crude oil itself is not very useful. Seperating the crude oil into useful components is called *refining*. The first step in refining is *fractional distillation*, called *straight-run distillation*. The crude oil is heated and at different temperatures different things leave the crude oil as vapours. These vapours are collected and futher refined to make the final products. This is determined by the number of carbon atoms in each compound of vapour. Boiling range, Number of Name Use degree C carbon atoms under 30 1-4 gas fraction heating oil 30-180 5-10 gasoline auto fuel 180-230 11-12 kerosene jet fuel 230-305 13-17 gas oil diesel,heating 305-405 18-25 heavy gas oil heating The residue is 1. Volatile oils: lub oil, paraffin wax,petroleum jelly. 2. Nonvolatile material: asphalt and petroleum coke.The gasoline fraction of straight-run is too SCANTY for the needs of our auto oriented society, and straight-run gasoline is of poor quality. To increase the QUANTITY and QUALITY of the gasoline fraction, the higher boiling fractions are subjected to *cracking* and *reforming*. That means we are going to take the diesel and heating oils and *crack* them into gasoline and other synthetic compounds (not found naturally). That way we will have enough gasoline. Catalytic cracking is the process of using high heat under high pressure in the presence of catalyst (acid washed aluminum silicate clay) to make gasoline from diesel and heating oil. The large molecules are broken down (cracked) into smaller molecules. Steam cracking will convert *alkanes* to *alkenes*. Catalytic reforming converts *aliphatic* compounds to *aromatic* compounds. The alkenes and aromatics are used as starting materials for plastics and other synthetic materials. The Automobile Engine High compression engines are relatively efficient for their weight, however continuous-chain hydrocarbons burn unevenly and cause knocking (pinging). Knocking decreases engine power and causes stress, wear and tear on engines. That means more maintenance and short engine life. Thats not good. Automobile Fuels Quality auto fuels contain branched alkanes and aromatic compounds, which burn more evenly than continous-chain compounds, fortunately cracking provides both,or we would still be driving wagons with horse teams. At one time ,*isooctane* (trivia name) was the alkane with the best anti-knock characteristic and *heptane* was the poorest. These two compounds were used to develope the octane rating system. Formulas... 2,2,4-trimethylpentane (real name),isooctane (trivia) the numbers tell how the molecules are arranged to each other. CH3(CH2)5CH3 is heptane To rate the quality of a gasoline, the fuel is compared with a mixture of isooctane and heptane and given an *octane number*. An octane number of 100 means it is the same as burning pure isooctane. An octane number of zero (0) is the same as burning pure heptane. An octane number of 75 is the equivalent to burning a mixture of 75% isooctane and 25% heptane. Lets stop here, keeping in mind we are talking about gas additives and what some people think they are doing to us, even claiming they use silver compounds to overcome them. Part two coming soon to a computer near you. Bless you Bob Lee -- oozing on the muggy shore of the gulf coast [email protected] -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
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