Paraxylene (PX) is the largest produced isomer of the xylene group, separated from the mixed xylene stream that results from the refining of petroleum. Almost all of the globally produced PX finds its demand in the polyester chain manufacture.
Para-Xylene is primarily used as a basic raw material in the manufacture of terephthalic acid (TPA), purified terephthalic acid (PTA) and dimethyl-terephthalate (DMT). TPA, PTA and DMT are used to manufacture polyethylene terephthalate (PET) saturated polyester polymers. Polyesters are used to produce yarn, fibres and films. PET bottles are widely used for carbonated beverages because of good carbon dioxide barrier properties. In addition, they are light-weight, shatter-resistant and possess high tensile strength.Polyester uses include:
- _ Carbonated and non-carbonated beverage containers
- _ Containers for household chemicals, toiletries, cosmetics, etc.
- _ Fabrics for curtains, upholstery, clothing, etc.
- _ Microwave oven packaging material
- _ Films for x-rays, magnetic tapes, photographic film and electrical insulatio
- _ Packaging for boil-in bags, processed meats, shrink films and blister packs
OX (Ortho Xylene)
Ortho-xylene is the second largest of the three commercial isomers of xylene. Most ortho-xylene consumption is dedicated to phthalic anhydride (PAN) production, the major use of which is in plasticizers for PVC, strongly tied to the housing market, in unsaturated polyester resins used in the manufacture of reinforced laminates for the construction and motor vehicle industries as well as in alkyd resins used in solvent-based paints. All handlers of ortho-xylene must fully understand and observe the “Material Safety Data Sheet (MSDS)” to prevent leakage since it is highly flammable and poisonous.
SM (Stryrene Monomer)
Styrene is one of the most important monomers produced by the chemical industry today. Styrene monomer is a basic building block of the plastics industry. The conventional method of producing styrene involves the alkylation of benzene with ethylene to produce ethylbenzene, followed by dehydrogenation of ethylbenzene to styrene. Styrene undergoes polymerization by all the common methods used in plastics technology to produce a wide variety of polymers and copolymers. Styrene is readily polymerized and copolymerized by both batch and continuous mass polymerization, emulsion, suspension and solution processes.
The most important products are solid polystyrene (PS), expandable polystyrene (EPS), styrene butadiene latex (SBL), acrylonitrile-butadiene-styrene/terpolymer (ABS), unsaturated polyester resins (UPR), and styrene-butadiene rubber (SBR). An approximate breakdown of styrene’s markets are:
- 54% solid polystyrene (PS)
- 8% expandable polystyrene (EPS)
- 8% styrene butadiene latex (SBL)
- 7% acrylonitrile-butadiene-styrene/terpolymer (ABS)
- 7% unsaturated polyester resins (UPR)
- 5% styrene-butadiene rubber (SBR)
Polystyrene is primarily used in packaging, disposables and low-cost consumer products. Expandable polystyrene beads are primarily used in food and beverage packaging, insulation and cushion packaging. Improved grades of resins are used in higher performance applications, such as home electronics and appliances. ABS and styrene acrylonitrile (SAN) have many uses in the consumer durables market.
Styrene-based polyesters enjoy long service life in both indoor and outdoor applications, e.g., polyester boats typically last longer than boats made from conventional materials. Thermoplastic elastomers are directly replacing natural and traditional synthetic rubbers in many established applications and entering new markets. Other applications include carpet backing (SB Latex), production of tires (SB Rubber) and castings for textiles and paper. Many products made from styrene are recyclable. Chevron Phillips Chemical along with other polystyrene producers formed the National Polystyrene Recycling Company (NPRC) to recycle post-consumer polystyrene. Recycled polystyrene is used in packaging, construction materials, video cassettes, office supplies and other useful products.
MTBE
MTBE(methyl tertiary-butyl ether) is a chemical compound that is manufactured by the chemical reaction of methanol and isobutylene. MTBE is produced in very large quantities (over 200,000 barrels per day in the U.S. in 1999) and is almost exclusively used as a fuel additive in motor gasoline. It is one of a group of chemicals commonly known as "oxygenates" because they raise the oxygen content of gasoline. At room temperature, MTBE is a volatile, flammable and colorless liquid that dissolves rather easily in water.
Over 90% of methyl tertiary butyl ether (MTBE) production is used in gasoline as an octane booster and oxygenate. With its high octane number, it is suitable where higher octane gasoline grades are sold. It has been favoured over ethanol because of its transportability, superior performance in reducing benzene and formaldehyde in gasoline, and its lower volatile organic compound content.
Ortho-xylene is the second largest of the three commercial isomers of xylene. Most ortho-xylene consumption is dedicated to phthalic anhydride (PAN) production, the major use of which is in plasticizers for PVC, strongly tied to the housing market, in unsaturated polyester resins used in the manufacture of reinforced laminates for the construction and motor vehicle industries as well as in alkyd resins used in solvent-based paints. All handlers of ortho-xylene must fully understand and observe the “Material Safety Data Sheet (MSDS)” to prevent leakage since it is highly flammable and poisonous.
Mixed xylene Uses
1) Solvent Grade MX: Primarily used as raw material for dye, organic pigment, perfume, plasticizer, medicines, etc., and as general solvents for paint, agricultural pesticide, medicines, etc.
2) Isomer Grade MX: Used as raw material for producing each o-, m-, p-Xylene product. O-Xylene product is produced through distillation using b.p, whereas m- and p-Xylene products are manufactured through the adsorption equipment given the similar differences in b.p between the two.