Paraffin wax (or petroleum wax) is a soft colorless solid derived from
petroleum,
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when ...
, or
oil shale
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...
that consists of a mixture of
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and
begins to melt above approximately , and its boiling point is above . Common applications for paraffin wax include
lubrication,
electrical insulation
An electrical insulator is a material in which electric current does not flow freely. The atoms of the insulator have tightly bound electrons which cannot readily move. Other materials—semiconductors and conductors—conduct electric current ...
, and
candles; dyed paraffin wax can be made into
crayons. It is distinct from
kerosene and other petroleum products that are sometimes called paraffin.
Un-dyed, unscented paraffin candles are odorless and bluish-white. Paraffin wax was first created by
Carl Reichenbach
Carl Ludwig von Reichenbach (full name: Karl Ludwig Freiherr von Reichenbach; February 12, 1788January 1869) was a German chemist, geologist, metallurgist, naturalist, industrialist and philosopher, and a member of the Prussian Academy of Scienc ...
in Germany in 1830 and marked a major advancement in candlemaking technology, as it burned more cleanly and reliably than
tallow candles and was cheaper to produce.
In chemistry, ''paraffin'' is used synonymously with ''
alkane'', indicating hydrocarbons with the general formula C
''n''H
2''n''+2. The name is derived from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''parum'' ("very little") + ''affinis'', meaning "lacking
affinity" or "lacking
reactivity", referring to paraffin's unreactive nature.
Properties
Paraffin
wax
Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to giv ...
is mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about , and a density of around 900 kg/m
3.
It is insoluble in water, but soluble in
ether,
benzene, and certain
esters. Paraffin is unaffected by most common chemical
reagents but
burns readily. Its heat of combustion is 42 MJ/kg.
:
Paraffin wax is an excellent
electrical insulator
An electrical insulator is a material in which electric current does not flow freely. The atoms of the insulator have tightly bound electrons which cannot readily move. Other materials—semiconductors and conductors—conduct electric current ...
, with a
resistivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows ...
of between 10
13 and 10
17 ohm metre.
This is better than nearly all other materials except some
plastics (notably
Teflon). It is an effective
neutron moderator and was used in
James Chadwick
Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspi ...
's 1932 experiments to identify the neutron.
Paraffin wax is an excellent material for
storing heat, with a
specific heat capacity of 2.14–2.9 J g
−1 K
−1 (
joules per
gram
The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram.
Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to th ...
kelvin) and a
heat of fusion of 200–220 J g
−1. Paraffin wax phase-change cooling coupled with retractable radiators was used to cool the electronics of the
Lunar Roving Vehicle during the crewed missions to the Moon in the early 1970s. Wax expands considerably when it melts and this allows its use in
wax element thermostats for industrial, domestic and, particularly, automobile purposes.
History
Paraffin wax was first created in 1830 by German chemist
Karl von Reichenbach
Carl Ludwig von Reichenbach (full name: Karl Ludwig Freiherr von Reichenbach; February 12, 1788January 1869) was a German chemist, geologist, metallurgist, natural history, naturalist, industrialist and philosopher, and a member of the Prussian A ...
when he attempted to develop a method to efficiently separate and refine waxy substances naturally occurring in petroleum. Paraffin represented a major advance in the candlemaking industry, because it burned cleanly and was cheaper to manufacture than other candle fuels. Paraffin wax initially suffered from a low melting point. This was remedied by adding
stearic acid. The production of paraffin wax enjoyed a boom in the early 20th century due to the growth of the oil and meatpacking industries, which created paraffin and stearic acid as byproducts.
Manufacturing
The feedstock for paraffin is
slack wax, which is a mixture of oil and wax, a byproduct from the refining of lubricating oil.
The first step in making paraffin wax is to remove the oil (de-oiling or de-waxing) from the slack wax. The oil is separated by crystallization. Most commonly, the slack wax is heated, mixed with one or more
solvents such as a
ketone and then cooled. As it cools, wax crystallizes out of the solution, leaving only oil. This mixture is filtered into two streams: solid (wax plus some solvent) and liquid (oil and solvent). After the solvent is recovered by distillation, the resulting products are called "product wax" (or "press wax") and "foots oil". The lower the percentage of oil in the wax, the more refined it is considered (semi-refined versus fully refined). The product wax may be further processed to remove colors and odors. The wax may finally be blended together to give certain desired properties such as melt point and penetration. Paraffin wax is sold in either liquid or solid form.
Applications
In industrial applications, it is often useful to modify the crystal properties of the paraffin wax, typically by adding
branching to the existing carbon backbone chain. The modification is usually done with additives, such as
EVA
Eva or EVA may refer to:
* Eva (name), a feminine given name
Arts, entertainment, and media Fictional characters
* Eva (Dynamite Entertainment), a comic book character by Dynamite Entertainment
* Eva (''Devil May Cry''), Dante's mother in t ...
copolymers,
microcrystalline wax
Microcrystalline waxes are a type of wax produced by de-oiling petrolatum, as part of the petroleum refining process. In contrast to the more familiar paraffin wax which contains mostly unbranched alkanes, microcrystalline wax contains a higher p ...
, or forms of
polyethylene. The branched properties result in a modified paraffin with a higher viscosity, smaller crystalline structure, and modified functional properties. Pure paraffin wax is rarely used for carving original models for
casting metal and other materials in the
lost wax process, as it is relatively brittle at room temperature and presents the risks of chipping and breakage when worked. Soft and pliable waxes, like
beeswax, may be preferred for such sculpture, but "
investment casting waxes," often paraffin-based, are expressly formulated for the purpose.
In a histology or pathology laboratory, paraffin wax is used to impregnate tissue prior to sectioning thin samples. Water is removed from the tissue through ascending strengths of alcohol (75% to absolute), and the tissue is cleared in an organic solvent such as
xylene. The tissue is then placed in paraffin wax for several hours, then set in a mold with wax to cool and solidify. Sections are then cut on a
microtome.
Other uses
*
Candle-making
*
Wax carving
*
Bicycle chain
A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simpl ...
lubrication
* Coatings for
waxed paper
Waxed paper (also wax paper, waxpaper, or paraffin paper) is paper that has been made moisture-proof and grease-proof through the application of wax.
The practice of oiling parchment or paper in order to make it semi-translucent or moisture-pro ...
or
waxed cotton
* Food-grade paraffin wax:
** Shiny coating used in
candy-making; although edible, it is nondigestible, passing through the body without being broken down
** Coating for many kinds of hard
cheese, like
Edam cheese
** Sealant for jars, cans, and bottles
** Chewing gum additive
*
Investment casting
* Anti-caking agent, moisture repellent, and dustbinding coatings for
fertilizers
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
* Agent for preparation of specimens for
histology
* Bullet lubricant – with other ingredients, such as olive oil and
beeswax
*
Phlegmatizing agent, commonly used to stabilise/desensitize
high explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ...
s such as
RDX
*
Crayons
* Solid propellant for
hybrid rocket
A hybrid-propellant rocket is a rocket with a rocket motor that uses rocket propellants in two different phases: one solid and the other either gas or liquid. The hybrid rocket concept can be traced back to the early 1930s.
Hybrid rockets avo ...
motors
* Component of
surfboard wax,
ski wax, and
skateboard wax
* Ink. Used as the basis for solid ink different color blocks of wax for thermal printers. The wax is melted and then sprayed on the paper producing images with a shiny surface
* Microwax:
food additive, a
glazing agent with
E number E905
*
Forensic investigation
Forensic science, also known as criminalistics, is the application of science to criminal and civil laws, mainly—on the criminal side—during criminal investigation, as governed by the legal standards of admissible evidence and criminal p ...
s: the nitrate test uses paraffin wax to detect nitrates and nitrites on the hand of a shooting suspect
*
Antiozonant
An antiozonant, also known as anti-ozonant, is an organic compound that prevents or retards damage caused by ozone. The most important antiozonants are those which prevent degradation of elastomers like rubber. A number of research projects study ...
agents: blends of paraffin and micro waxes are used in rubber compounds to prevent
cracking of the rubber; the admixture of wax migrates to the surface of the product and forms a protective layer. The layer can also act as a
release agent
A release agent (also mold release agent, release coating, or mold release coating) is a chemical used to prevent other materials from bonding to surfaces. It can provide a solution in processes involving mold release, die-cast release, plastic r ...
, helping the product separate from its
mould.
* Mechanical
thermostats
A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint.
Thermostats are used in any device or system tha ...
and
actuators
An actuator is a component of a machine that is responsible for moving and controlling a mechanism or system, for example by opening a valve. In simple terms, it is a "mover".
An actuator requires a control device (controlled by control signal) an ...
, as an expansion medium for activating such devices
[
* As a potting material to encapsulate electronic components such as guitar pickups, transformers, and inductors, to prevent moisture ingress and to reduce electromagnetically-induced acoustic noise and microphonic effects
* Textile manufacturing processes, such as that used for Eisengarn thread.
* Thickening agent in many ]paintballs
Paintball is an equipment-intensive sport and in order to safely conduct a game, every player requires a marker with propellant to fire the paint, a mask to protect the eyes and face, paintballs, and a loader to hold them. To ensure safety off t ...
* Moisturiser in toiletries
Personal care or toiletries are consumer products used in personal hygiene, personal grooming or for beautification.
Products
Personal care includes products as diverse as cleansing pads, colognes, cotton swabs, cotton pads, deodorant, eye li ...
and cosmetics such as Vaseline
Vaseline ()Also pronounced with the main stress on the last syllable . is an American brand of petroleum jelly-based products owned by transnational company Unilever. Products include plain petroleum jelly and a selection of skin creams, soa ...
.
* Prevents oxidation on the surface of polished steel and iron
* Phase change material for thermal energy storage
Thermal energy storage (TES) is achieved with widely different technologies. Depending on the specific technology, it allows excess thermal energy to be stored and used hours, days, months later, at scales ranging from the individual process, ...
** Used by MESSENGER (Mercury spacecraft), when the spacecraft was unable to radiate excessive heat.
* Manufacture of boiled leather armor and books
* Neutron radiation
Neutron radiation is a form of ionizing radiation that presents as free neutrons. Typical phenomena are nuclear fission or nuclear fusion causing the release of free neutrons, which then react with nuclei of other atoms to form new isotopes— ...
shielding
* Wax baths for occupational and physical therapies, and cosmetic treatments
* Used for wood finishing
Wood finishing refers to the process of refining or protecting a wooden surface, especially in the production of furniture where typically it represents between 5 and 30% of manufacturing costs.
Finishing is the final step of the manufacturing ...
* Used as a fuel for fire breathing
* Used in Lava Lamps
Occupational safety
People can be exposed to paraffin in the workplace by breathing it in, skin contact, and eye contact. The National Institute for Occupational Safety and Health
The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...
(NIOSH) has set a recommended exposure limit
A recommended exposure limit (REL) is an occupational exposure limit that has been recommended by the United States National Institute for Occupational Safety and Health. The REL is a level that NIOSH believes would be protective of worker safet ...
(REL) for paraffin wax fume exposure of 2 mg/m3 over an 8-hour workday.
See also
* Oligomer
* Ozokerite
References
External links
*
Odd Uses of Paraffin
, Scientific American, 13 July 1878, p. 19
{{Authority control
Waxes
Alkanes
Petroleum products
Food additives
E-number additives