Antifreeze production

It is also used as a corrosion inhibitor in automotive antifreeze products. 

Laws have been enacted in many states in an attempt to prevent the sale and distribution of deleterious antifreeze products, such as salt solutions or petroleum coolants. Even ethylene glycol engine coolants must be evaluated by testing and comparison of test results with specifications for engine coolant concentrate, such as ASTM D 3306. These tests ensure desired levels of antifreeze coolant concentrate and inhibitor are available to adequately protect cooling systems against freezing, boilover and corrosion (Fig. 2). 

Exposure to oxalates may occur through consumption of certain plants and foods in which they are naturally present (see above). Exposure may also occur through contact with, or inhalation of, commercial products (e.g., bleaches, cleaners) or as a result of accidental ingestion or contact with some commercial antifreeze products that contain ethylene glycol, which is metabolized in vivo to oxalates. 

Ethylene glycol, present in antifreeze products, may be ingested accidentally or for the purpose of inebriation or suicide. Ethylene glycol itself is relatively nontoxic, and its initial CNS effects resemble those of ethanol. However, metabolism of ethylene glycol by ADH results in the formation of a number of acid metabolites, including oxalic acid and glycolic acid (Figure 34-16). 

Ethyl alcohol is used in antifreeze products, and also as a fuel a solution of 70-85% of ethyl alcohol is commonly used as a disinfectant. It kills organisms by denaturing their proteins and dissolving their liquids and it is effective against most bacteria, fungi and many viruses though ineffective against bacterial spores. 

Ethylene Cracking hydrocarbons from oil and natural gas Plastics, antifreeze production, fibers, and solvents... 

Some commercial automobile antifreeze products use propylene glycol (CjHjOj) instead of ethylene glycol, because of its lower toxicity (especially in pets). 

Chemical Specialties Manufacturers Association 1001 Connecticut Avenue, NW Washington, D.C. 20036 Standard Reference TestingMaterials for insecticides (see Insect control technology), cleaning products, sanitizers, brake fluids, corrosion inhibitors (see Corrosion and corrosion control), antifreezes, poHshes, and floor waxes. 

The absorption of SO for oleum production is carried out over a relatively narrow temperature range. The upper temperature is set to provide a reasonable partial pressure driving force for the oleum concentration used. The lower practical temperature limit is the freezing point of oleums, which is high enough to be a problem in shipping and handling as well. For some oleum uses it is practical to add small amounts of HNO as an antifreeze (100). 

When antifreeze becomes unsuitable for use, either because of depletion of inhibitors, presence of corrosion products or corrosive ions, or degradation of the fluid, recycling and reuse of the antifreeze, rather than disposal, may be considered. Although ethylene glycol is readily biodegraded in typical municipal waste treatment faciHties, antifreeze disposal becomes problematic because the coolant may contain hazardous quantities of heavy metals picked up from the cooling system. Recycling may be economically preferred over coolant disposal and reduces the concern for environmental impact. 

Ideally, a system for recycling spent antifreeze consists first of the removal of the deleterious contaminants such as the corrosion products, corrosive ions, degradation products, and remaining inhibitors. Then the clean fluid could be reinhibited to a known concentration of both inhibitors and glycol. 

An explosion and fire (March 13, 1991) occurred at an ethylene oxide unit at Union Carbide Chemicals Plastics Co. s Seadrift plant in Port Lavaca, TX, 125 miles southwest of Houston. The blast killed one, injured 19, and idled the facility, that also produces ethylene, ethylene glycol, glycol ether ethanolamines, and polyethylene. Twenty-five residents were evacuated for several hours as a safety precaution. The plant lost all electrical power, for a few days, because its cogeneration unit was damaged. The Seadrift plant, with 1,600 workers, is capable of making 820 million lb per year of ethylene oxide which is one-third of Carbide s worldwide production of antifreeze, polyester fibers, and surfactants Seadrift produces two thirds of Carbide s worldwide production of polyethylene. 

ETHYLENE We discussed ethylene production in an earlier boxed essay (Section 5.1), where it was pointed out that the output of the U.S. petrochemical industry exceeds 5 x 10 ° Ib/year. Approximately 90% of this material is used for the preparation of four compounds (polyethylene, ethylene oxide, vinyl chloride, and styrene), with polymerization to polyethylene accounting for half the total. Both vinyl chloride and styrene are polymerized to give poly(vinyl chloride) and polystyrene, respectively (see Table 6.5). Ethylene oxide is a starting material for the preparation of ethylene glycol for use as an antifreeze in automobile radiators and in the production of polyester fibers (see the boxed essay "Condensation Polymers Polyamides and Polyesters" in Chapter 20). 

Current world production of ethylene glycol is approximately 15 billion pounds. Most of that is used for producing polyethylene terephtha-late (PET) resins (for fiber, film, bottles), antifreeze, and other products. Approximately 50% of the world EG was consumed in the manufacture of polyester fibers and another 25% went into the antifreeze. 

EG consumption in the US was nearly 1/3 of the world s. The use pattern, however, is different about 50% of EG is consumed in antifreeze. The US production of ethylene glycol was 5.55 billion pounds in 1994, the 30th largest volume chemical. 

Typical BW antifoam emulsion products include SAG 10 and SAG 30 (10 and 30% milky white emulsions, each with a viscosity of 2,000 cS at 25 °C) from Union Carbide Corporation. These same products also are used for food processing (under FDA 21CFR 173.340), for petroleum processing (as amine scrubbers, gas-oil separators, etc.), and as functional chemicals (antifreezes, hydraulic fluids, cutting oils, etc.). 

So when someone warns that there is antifreeze in your toothpaste, ask which antifreeze. Some are illegal adulterants added by criminal cost-cutters, and their products are quickly recalled. Others (like glycerin, propylene glycol, or salt) are generally recognized as safe and are reasonable household ingredients. 

Ethylene glycol is the principal ingredient in automobile antifreeze and is also used to make polyester textile hbers such as Dacron. Glycerine is recovered as a by-product in the manufacture of soap and is used in cosmetics. Both glycerine and pentaerythritol are also used in the manufacture of paint and explosives. 

Ethylene oxide is an important intermediate for ethylene glycol (antifreeze) and for plastics, plasticizers, and many other products [R.A. van Santen and H.P.C.E. Kui-pers, Adv. Catal. 35 (1987) 265]. In Chapter 1 we explained that the replacement of the traditional manufacturing process - which generated 1.5 mole of byproducts per 1 mole of epoxide - by a catalytic route based on silver catalysts is a major success story with respect to clean chemistry (Fig. 9.16). 

Spent antifreeze formulations can be purified before recycling. If antifreeze is kept separate from waste oils, it can be easily treated and recycled into a new product. 

PET fiber is made from raw materials that are cheap and available, due to the large manufacturing infrastructure it shares with other common products, e.g. antifreeze and soda bottles. The polymerization byproducts are non-polluting, and the polymer can be recycled. 

Propanediol. In its racemic form, 1,2-propanediol is a petroleum-based high-volume chemical with an aimual production of over 500,0001, mostly used to manufacture the unsaturated polyester resins, yet also featuring excellent antifreeze properties. Enantiomerically pure (/ )-1,2-propanediol accumulates along two different pathways via DAHP (3-deoxy-D-flrahmo-heptulosonic acid 7-phosphate) and methylglyoxal, which then is reduced with either... 

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