Wax


Wax
Cetyl palmitate, a typical wax ester.
Commercial honeycomb foundation, made by pressing beeswax between patterned metal rollers.

Wax refers to a class of chemical compounds that are plastic (malleable) near ambient temperatures. Characteristically, they melt above 45 °C (113 °F) to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents. All waxes are organic compounds, both synthetic and naturally occurring.

Contents

Types

Waxes are organic compounds that characteristically consist of long alkyl chains. Natural waxes are typically esters of fatty acids and long chain alcohols. Synthetic waxes are long-chain hydrocarbons lacking functional groups.

Plant and animal waxes

Waxes are biosynthesized by many plants and animals. They typically consist of several components, including wax esters, wax acids, wax alcohols, and hydrocarbons. Wax esters are typically derived from a variety of carboxylic acids and a variety of fatty alcohols. The composition depends not only on species, but also on geographic location of the organism. Because they are mixtures, naturally produced waxes are softer and melt at lower temperatures than the pure components.

Animal waxes

The most commonly known animal wax is beeswax, but other insects secrete waxes. A major component of beeswax is the ester myricyl palmitate substance which is used in constructing their honeycombs. Its melting point is 62-65 °C. Spermaceti occurs in large amounts in the head oil of the sperm whale. One of its main constituents is cetyl palmitate, another ester of a fatty acid and a fatty alcohol. Lanolin is a wax obtained from wool, consisting of esters of sterols.[1]

Plant waxes

Especially in warm climates, plants secrete waxes as a way to control evaporation and hydration.[2] From the commercial perspective, the most important wax is Carnauba wax, a hard wax obtained from the Brazilian palm. Containing the ester myricyl cerotate, it has many applications. Other more specialized vegetable waxes include candelilla wax, ouricury wax, sugarcane wax, retamo wax, jojoba oil. The epicuticular waxes of plants are mixtures of substituted long-chain aliphatic hydrocarbons, containing alkanes, fatty acids, primary and secondary alcohols, diols, ketones, aldehydes.[3]

Petroleum derived waxes

Although most natural waxes are esters, paraffin waxes are hydrocarbons, mixtures of alkanes usually in a homologous series of chain lengths. These materials represent a significant fraction of petroleum. They are refined by vacuum distillation. Paraffin waxes are mixtures of saturated n- and isoalkanes, naphthenes, and alkyl- and naphthene-substituted aromatic compounds. The degree of branching has an important influence on the properties. Millions of tons of paraffin waxes are produced annually. They are used in adhesives, in foods (such as chewing gum and cheese wrapping), in cosmetics, and as coatings.

Montan wax

Montan wax is a fossilized wax extracted from coal and lignite. It is very hard, reflecting the high concentration of saturated fatty acids and alcohols, not esters that characterize softer waxes. Although dark brown and smelly, they can be purified and bleached to give commercially useful products.

Polyethylene and related derivatives

Some waxes are obtained by cracking polyethylene at 400 °C. The products have the formula (CH2)nH2, where n ranges between about 50 and 100. As of 1995, about 200 million kilograms/y were consumed.[2]

Uses

Waxes are mainly consumed industrially as components of complex formulations, often for coatings.[2] The main use of polyethylene and polypropylene waxes is in the formulation of colourants for plastics. Waxes confer matting effects and wear resistance to paints. Polyethyelene waxes are incorporated into inks in the form of dispersions to decrease friction. They are employed as release agents. They are also used as slip agents, e.g. in furniture, and corrosion resistance.

Candles

Waxes and hard fats such as tallow have been used to make candles, used for lighting and decoration in a number of religious traditions, including Christianity and Hinduism, as well as various neo-pagan religions such as Wicca. The Emperor Constantine is reported to have called for the use of candles during an Easter service in the 4th century AD. Candles continue to be used today by Christians[4] in worship as symbols of the light of Christ. In the Roman Catholic Church, beeswax candles are used, since a colony of bees is a celibate sisterhood with a single mother.[5] Candles of wax or tallow took the place of lamps used in various Jewish rituals such as the Sabbath lights; in the Havdalah ceremony; and the Hanukkah lights. A synagogue had to be well lit, and pious folk used to donate candles for the purpose. On the basis of the verse: 'The soul of man is a candle of the Lord', a special candle which burns twenty-four hours is kindled on the anniversary of the death of a near relative (Yahrzeit) and often two lighted candles are placed at the head of the corpse awaiting burial.[6] In fact, according to the Shulchan Aruch, wax candles are the only kind of light which can be used for Bedikat Chametz, and not tallow or oil.[7] Candles have also played a role in pagan religions and in modern humanist festivals. Virtually all rituals in Wicca include the lighting of altar candles, where two main candles are often used to represent the God and the Goddess; and the lighting of candles is a central theme at the Wiccan holiday of Brigid or Imbolc, which is also known as Candlemas or the Feast of the Waxing Light. Wax candles were also used in secular life for lighting, signals in warfare, safety in travel and for time keeping, and are still in popular use today to provide soft lighting for meals and other social activities.

Other uses

Sealing wax was used to close important documents in the Middle Ages. Waxes are used to make wax paper, impregnating and coating paper and card to waterproof it or make it resistant to staining, or to modify its surface properties. Waxes are also used in shoe polishes, wood polishes, and automotive polishes, as mold release agents in mold making, as a coating for many cheeses, and to waterproof leather and fabric. Wax has been used since antiquity as a temporary, removable model in lost-wax casting of gold, silver and other materials.

Wax with colorful pigments added has been used as a medium in encaustic painting, and is used today in the manufacture of crayons and colored pencils. Carbon paper, used for making duplicate typewritten documents was coated with carbon black suspended in wax, typically montan wax, but has largely been superseded by photocopiers and computer printers. In another context, lipstick and mascara are blends of various fats and waxes colored with pigments, and both beeswax and lanolin are used in other cosmetics. Ski wax is used in skiing and snowboarding. Also, the sports of surfing and skateboarding often use wax to enhance the performance. Beeswax or coloured synthetic wax is used to decorate Easter eggs in Ukraine and the Czech Republic. Paraffin wax is used in making chocolate covered bon-bons. Wax is also used in wax bullets, which are used as simulation aids.

Wax candle.  
Wax-decorated Easter eggs as made in Ukraine and the Czech Republic.  
A lava lamp is a novelty item that contains wax melted from below by a bulb. The wax rises and falls in decorative, molten blobs.  

Wax types

Animal waxes

Vegetable waxes

Mineral waxes

Petroleum waxes

Synthetic waxes

  • Polyethylene waxes - based on polyethylene
  • Fischer-Tropsch waxes
  • Chemically modified waxes - usually esterified or saponified
  • substituted amide waxes
  • polymerized α-olefins

See also

References

  1. ^ Wilhelm Riemenschneider1 and Hermann M. Bolt "Esters, Organic" Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a09_565.pub2
  2. ^ a b c Uwe Wolfmeier, Hans Schmidt, Franz-Leo Heinrichs, Georg Michalczyk, Wolfgang Payer, Wolfram Dietsche, Klaus Boehlke, Gerd Hohner, Josef Wildgruber "Waxes" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. doi:10.1002/14356007.a28_103.
  3. ^ EA Baker (1982) Chemistry and morphology of plant epicuticular waxes. In The Plant Cuticle. Ed. DF Cutler, KL Alvin, CE Price. Academic Press. ISBN 0-12-199920-3
  4. ^ The Hive and the Honey Bee, ed. Dadant & sons, revised 1975, p. 540
  5. ^ Butler, C.G. (1954) The world of the honeybee. Collins, New Naturalist series, No. 29
  6. ^ Jacobs, Louis (1995) "The Jewish Religion - a Companion" Oxford University Press
  7. ^ Shulchan Aruch: Orach Chayim: 433:2

External links


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Synonyms:

Look at other dictionaries:

  • Wax — Wax, n. [AS. weax; akin to OFries. wax, D. was, G. wachs, OHG. wahs, Icel. & Sw. vax, Dan. vox, Lith. vaszkas, Russ. vosk .] [1913 Webster] 1. A fatty, solid substance, produced by bees, and employed by them in the construction of their comb;… …   The Collaborative International Dictionary of English

  • wax — ● wax nom masculin (anglais wax, cire) En Afrique noire, tissu de coton imprimé de qualité supérieure. wax n. m. Tissu de coton imprimé d un dessin évoquant des craquelures, obtenu par un procédé à la cire. (En appos.) Un tissu wax. Un pagne wax …   Encyclopédie Universelle

  • Wax — Wax, v. t. [imp. & p. p. {Waxed}; p. pr. & vb. n. {Waxing}.] To smear or rub with wax; to treat with wax; as, to wax a thread or a table. [1913 Webster] {Waxed cloth}, cloth covered with a coating of wax, used as a cover, of tables and for other… …   The Collaborative International Dictionary of English

  • Wax — (w[a^]ks), v. i. [imp. {Waxed}; p. p. {Waxed}, and Obs. or Poetic {Waxen}; p. pr. & vb. n. {Waxing}.] [AS. weaxan; akin to OFries. waxa, D. wassen, OS. & OHG. wahsan, G. wachsen, Icel. vaxa, Sw. v[ a]xa, Dan. voxe, Goth. wahsjan, Gr. ? to… …   The Collaborative International Dictionary of English

  • Wax — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. {{{image}}}   Sigles d une seule lettre   Sigles de deux lettres > Sigles de trois lettres …   Wikipédia en Français

  • wax — wax1 [waks] n. [ME < OE weax, akin to Ger wachs < IE * wokso < * weg , to weave, prob. < base * (a)we , to WEAVE] 1. a plastic, dull yellow substance secreted by bees for building cells; beeswax: it is hard when cold and easily molded …   English World dictionary

  • wax|y — «WAK see», adjective, wax|i|er, wax|i|est. 1. like wax. 2. made of wax; containing wax; waxen. 3. abounding in or covered w …   Useful english dictionary

  • wax — ‘soft oily substance’ [OE] and the now archaic wax ‘grow, become’ [OE] are distinct words. The former comes (together with German wachs, Dutch was, Swedish vax, and Danish vox) from a prehistoric Germanic *wakhsam. This in turn was descended from …   The Hutchinson dictionary of word origins

  • wax — ‘soft oily substance’ [OE] and the now archaic wax ‘grow, become’ [OE] are distinct words. The former comes (together with German wachs, Dutch was, Swedish vax, and Danish vox) from a prehistoric Germanic *wakhsam. This in turn was descended from …   Word origins

  • wax|en — «WAK suhn», adjective. 1. of wax; made of wax: »For now my love is thaw d; Which, like a waxen image gainst a fire Bears no impression of the thing it was (Shakespeare). 2. Figurative. like wax; smooth, soft, and pale: »Her skin is waxen. 3.… …   Useful english dictionary

  • wax — verb. In the meaning ‘to assume a specified tone or state’, wax is followed by an adjective, not an adverb: to wax lyrical, to wax enthusiastic, etc.: • When the Roman soldiers were asked to take part in the Claudian invasion of 43, they waxed… …   Modern English usage


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