Paraffin wax

Paraffin (Latin parum affinis, somewhat akin 'or' unreactive ') refers to a mixture of alkanes (saturated hydrocarbons) with the general empirical formula C n H 2n 2. The number n is between 18 and 32, the molar mass so that melts 275-600 grams per mole of paraffin wax between 50 and 60 ° C, soft paraffin at about 45 ° C. The microcrystalline waxes have even freezing points between 70 and 80 ° C and containing chain lengths ( n ) of up to 75 carbon atoms. Between the hard paraffins and microcrystalline waxes, the so-called intermediates that have freezing points of 60 to 70 ° C. The heat of fusion of between 200 and about 240 kJ / kg. Liquid paraffins are listed in the CAS directory under CAS 8012 -95 1, or in EINECS under EC 232-384-2, their density is from 0.81 to 0.89 g / cc and its boiling point is above 250 ° C.

Paraffin was discovered in 1830 by the Swabian scientist Karl von Reichenbach during a series of tests on elements of wood tar.

• 4.1 Hard paraffins
• 4.2 micro-waxes

Special paraffins

Due to different compositions, methods of preparation and different uses are paraffins as microcrystalline wax, ceresin ( mineral wax, paraffin wax), petrolatum sold (Vaseline ) or petroleum.

Properties

The properties of the paraffins can be derived directly from the homologous series of alkanes. Paraffin is a waxy, flammable, odorless and tasteless, non-toxic, electrically insulating, water-repellent, zusammenschmelzbar with fats and waxes, but to many chemicals unreactive ( inert). For example, it is quite resistant to sulfuric acid, bromine and cold nitric acid. In pure form, it is white translucent. It is insoluble in water but soluble in benzene, ether and chloroform. Paraffins are composed of unbranched ( n ) and branched (iso- ) alkanes. A distinction is made between

• Thin liquid paraffin ( paraffin perliquidum ), which have a viscosity of 25 to 80 mPa · s,
• Viscous paraffin ( Paraffinum subliquidum ) having as an oily liquid has a viscosity of 110-230 mPa · s and
• Hard paraffin ( paraffin solidum ), who as a solid mass a solidification temperature of 50 to 62 ° C. In hard paraffins n- alkanes dominate the other hand, in the micro waxes iso- alkanes.

Paraffins having a particularly large increase in volume by up to 10 % when heated to the phase transition from solid to liquid.

Hazards

According to the current safety data paraffin is classified according to the criteria of Directives 67/548/EEC or 1999/45/EC or Regulation ( EC) No 1272/2008 classified as dangerous for humans and the environment. Due to the variety of applications - for example, as fuel for candles, as components of drugs, protection of food, as a cosmetic ingredient - also an application-specific approach is necessary to evaluate possible risks. Different scenarios of exposure such as Inhalation, dermal application or internal administration need to be considered product-specific. For mineral oils in lip care products are, for example, because of the possible ingestion of the product the criteria defined for the food industry.

Paraffin in cosmetics

Highly purified paraffins of different consistency ( liquid oils to solids ) have been used for many decades in cosmetic products such as creams, lotions and lipsticks. You have film-forming, protective and hydrophobic properties that promote shine education and give consistency.

The Federal Office of Consumer Protection expected of paraffin in cosmetic products to any damaging effect and includes allergic reactions largely.

The expert groups CIR ( Cosmetic Ingredient Review - United States of America ) assume that when applied topically paraffins do not penetrate into the skin and therefore assumes no risk from these substances.

Stiftung Warentest responded to a request to paraffin: "(...) natural cosmetic companies often waive this ingredient with the argument that paraffin would like a movie set on the skin and prevent them from breathing. Not only the manufacturers of conventional cosmetics counter that but dermatologists and cosmetic chemists: For the paraffins and the concentrations used in cosmetics is used to expect nothing harmful for the skin. "

The Öko-Test magazine warns against more than 10% paraffin in skin care products and evaluates creams containing more than 10% in the test results from massive as this could favor the dehydration of the skin and thus the formation of wrinkles. Öko-Test makes the following about this: " paraffins. Collective name for numerous artificial substances from crude oil (...) hinder the natural regulatory mechanisms (...) can accumulate in the liver, kidney and lymph nodes (...)"

Production

Paraffin is obtained from the so-called oil -sections of the vacuum distillation. Arise in the dewaxing as a byproduct the paraffin Gatschen which still contain 2-30 % oil shares. For these Gatschen is obtained by de-oiling with different oil separation process ( Schwitzentölung, solvent de-oiling, Sulzer Kristallisationsentölung ) the slack. The slack is then further refined (see below). In addition, it is also from brown coal, produced from bituminous shale and Torfkohlen. More recently, with the Fischer- Tropsch process ( Sasol, Shell) synthetic paraffins produced are becoming increasingly important. These consist, in contrast to mineral oil products mainly stemmed from straight-chain n- alkanes.

In the recovery of paraffins also as a by- product of paraffin oils, which can be further refined into white oils, which serve as high-quality lubricants. Furthermore, refined white oils come in the pharmaceutical industry and in the production of Vaseline.

Hard paraffins

The hard - and Intermediate - paraffins are produced from Gatschen. This Gatschen fall in the deparaffinization of engine oils as a byproduct. The Gatschen be freed with the help of solvents, condensation and crystallization processes ( most modern method of Sulzer Chemtech ) of oil residue. They are then refined slack waxes ( hydrogenation or bleaching process ), whereby aromatics, sulfur and nitrogen compounds are converted or removed. By refining produces a white, odorless product which can be used in the food, cosmetics (Vaseline ) and pharmaceutical industries.

Microcrystalline waxes

(Also known as micro-crystalline waxes ) microcrystalline waxes are however obtained from the vacuum residue of the oil refinery motor, i.e., in this case a special need to refining processes ( for example, propane deasphalting ) the heavy crude oil components are removed. Thereafter, the flow (dewaxing, purification and refining ) is analogous to the other paraffins.

Use

The uses of paraffin are very diverse due to its properties and non-toxicity. The main areas of application are as fuel, sealing, maintenance and preservation.

So it is used as a fuel, for example, in candles, oil lamps, in African countries for the hotplate in the huts, fire starter, when fire breathing and fire juggling, to impregnate the wood of matches or as a solid propellant for hybrid rocket.

The water-repellent and insulating properties are exploited in the insulation of submarine cables, sealing of glasses and bottles (see Parafilm ), as a water- repellent ( hydrophobic ) coating or impregnation of paper, textiles, insulators, commercial explosives for moisture protection, the production of wax dispersions for the impregnation of wood materials, as liquid paraffin for the maintenance of wood surfaces and as a paint polish additive.

In the cosmetic industry it serves as a skin care oil, the military as an additive in Tarnschminke and medicine as a binder in ointments for preserving anatomical specimens ( waxing ), for the preparation of microscopic specimens, as a laxative to help the stool, as an antidote for poisoning by orally ingested, fat-soluble toxins ( Resorptionsverhinderung ) and in archeology for preparation of archaeological finds.

Other applications are:

• Outbreak Defense in keeping ants.
• As bud spray in crop protection ( larvae by paraffin film suffocates )
• In physical therapy as paraffin mud
• Crayons
• In tire manufacturing as ozone protection
• As a lens for concentrating microwave
• Storage medium in latent heat storage ( among others in the solar thermal )
• As a moderator in neutron sources
• As an organic binder in the pressing granules in the carbide production

Important products

The main customers of paraffin candles is the industry ( tea candles, household candles, decoration candles ) worldwide. It is cheaper than the stearin, which is derived from animal or vegetable products.

Paraffin is used as a raw material for ointments and creams ( eg in the form of petroleum jelly), for cosmetic and medical products (eg lipsticks), care and cleaning products for wood and metal, for car paints or shoe creams. Liquid paraffins (e.g., Nujol ) can be used as a mild laxative, and as a suspending agent in the IR - spectroscopy.

In the manufacture of cheese with some grades, it serves as a coating of the cortex in order to preserve the loaf and protected from drying out, for example in the Edam or Gouda. Furthermore, it is used in the preparation of chewing gum and confectionery, as paraffin as the release agent prevents the adhesion of coated tablets with sugar glaze under humidity. Vaseline is used as protection against the cold cream, by suppressing the evaporation of water from exposed facial skin and skin also thickens, as a lubricant and as a sealant for glass joints.

Large quantities are also used in corrosion protection in the auto industry ( flood waxes) or as an additive to rubber products such as tires (light waxes, protective ozone waxes). Photoprotective waxes can also be manufactured from synthetic waxes obtained by the Fischer- Tropsch synthesis.

A further application is the Histology: Tissue samples are in particular paraffins (with plastic additives to improve the cuttability, for example, from Merck ) was poured, and then cut.

English language

In American, the term paraffin same sense as in English. In British English, a supplement is necessary, otherwise it is misleading: paraffin oil means petroleum ( British Petroleum, and occasionally stone oil is petroleum / crude oil) and paraffin wax is the paraffin described in this article.