Alkenes Information (Double Bond, Pi Bond) @ Petr0.com

In organic chemistry Organic chemistry is a discipline within chemistry that involves the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives. These compounds may contain any number of other elements, including hydrogen, nitrogen, oxygen, the halogens as well as, an alkene, olefin, or olefine is an unsaturated chemical compound A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together in a defined spatial arrangement by chemical bonds containing at least one carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of-to-carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of double bond A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, and other covalent bonds. In short, the attraction-to-repulsion stability that forms between atoms when they share electrons is known as covalent bonding.^[1] The simplest acyclic alkenes, with only one double bond and no other functional groups In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of. However, its relative reactivity can be, form an homologous series In chemistry, a homologous series is a series of organic compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a result of increase in molecular size and mass . For example, ethane has a higher boiling point than methane of hydrocarbons In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls. Aromatic hydrocarbons , alkanes, alkenes, cycloalkanes and alkyne-based compounds are different types of hydrocarbons with the general formula C_nH_2n.^[2]

The simplest alkene is ethylene Ethylene is a gaseous organic compound with the formula C2H4. It is the simplest alkene (older name: olefin from its oil-forming property). Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and also has a role in biology as a hormone. Ethylene is the most (C₂H₄), which has the International Union of Pure and Applied Chemistry The International Union of Pure and Applied Chemistry , pronounced /ˈaɪjuːpæk/, is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science (ICSU). The international headquarters of IUPAC is located in Zürich, Switzerland. The (IUPAC) name ethene. Alkenes are also called olefins (an archaic synonym, widely used in the petrochemical Petrochemicals are chemical products derived from petroleum. Some chemical compounds made from petroleum are also obtained from other fossil fuels such as coal or natural gas, or renewable sources such as corn or sugar cane industry). Aromatic In organic chemistry, the structures of some rings of atoms are unexpectedly stable. Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. It can also be considered a manifestation of cyclic compounds are often drawn as cyclic alkenes, but their structure and properties are different and they are not considered to be alkenes.^[2]

Structure

Bonding

Ethylene (ethene), showing the pi bond in green.

Like single covalent bonds A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, and other covalent bonds. In short, the attraction-to-repulsion stability that forms between atoms when they share electrons is known as covalent bonding, double bonds can be described in terms of overlapping atomic orbitals, except that, unlike a single bond (which consists of a single sigma bond In chemistry, sigma bonds are the strongest type of covalent chemical bond. Sigma bonding is most clearly defined for diatomic molecules using the language and tools of symmetry groups. In this formal approach, a σ-bond is symmetrical with respect to rotation about the bond axis. By this definition, common forms of sigma bonds are s+s, pz+pz, and), a carbon-carbon double bond consists of one sigma bond In chemistry, sigma bonds are the strongest type of covalent chemical bond. Sigma bonding is most clearly defined for diatomic molecules using the language and tools of symmetry groups. In this formal approach, a σ-bond is symmetrical with respect to rotation about the bond axis. By this definition, common forms of sigma bonds are s+s, pz+pz, and and one pi bond In chemistry, pi bonds are covalent chemical bonds where two lobes of one involved electron orbital overlap two lobes of the other involved electron orbital. Only one of the orbital's nodal planes passes through both of the involved nuclei. This double bond is stronger than a single covalent bond A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, and other covalent bonds. In short, the attraction-to-repulsion stability that forms between atoms when they share electrons is known as covalent bonding (611 kJ The joule , named after James Prescott Joule, is the derived unit of energy in the International System of Units. It is the energy exerted by the force of one newton acting to move an object through a distance of one metre. In terms of dimensions:/mol The mole is the SI base unit of amount of substance; one of a few units used to measure this physical quantity. The name "mole" is an 1897 translation of the German Mol, coined by Wilhelm Ostwald in 1893, although the related concept of equivalent mass had been in use at least a century earlier. The name is assumed to be derived from the for C=C vs. 347 kJ/mol for C—C) ^[1] and also shorter with an average bond length In molecular geometry, bond length or bond distance is the average distance between nuclei of two bonded atoms in a molecule of 1.33 Angstroms The ångström or angstrom (pronounced /ˈæŋstrəm/; Swedish: [ˈɔŋstrøm]) is an internationally recognized unit of length equal to 0.1 nanometre or 1 × 10−10 metres. It is named after Anders Jonas Ångström. Although accepted for use, it is not formally defined within the International System of Units (SI) (133 pm A picometre is a unit of length in the metric system, equal to one trillionth, i.e. (1/1,000,000,000,000) of a metre, which is the current SI base unit of length. It can be written in scientific notation as 1×10−12 m, or as 1 E−12 m in engineering notation — both meaning 1 m / 1,000,000,000,000).

Each carbon of the double bond uses its three sp² hybrid orbitals In chemistry, hybridisation is the concept of mixing atomic orbitals within an atom to form new hybrid orbitals. It is an integral part of the valence bond theory to form sigma bonds to three atoms. The unhybridized 2p atomic orbitals, which lie perpendicular to the plane created by the axes of the three sp² hybrid orbitals, combine to form the pi bond. This bond lies outside the main C—C axis, with half of the bond on one side and half on the other.

Rotation about the carbon-carbon double bond is restricted because it involves breaking the pi bond, which requires a large amount of energy (264 kJ/mol in ethylene). As a consequence, substituted alkenes may exist as one of two isomers In chemistry, isomers are compounds with the same molecular formula but different structural formulas. The word is derived from the Greek ισομερης, isomerès; isos = "equal", méros = "part". There are many different classes of isomers, like stereoisomers, enantiomers, geometrical isomers, et cetera . Isomers do not, called cis or trans isomers. More complex alkenes may be named using the E-Z notation E-Z notation, or the E-Z convention is the IUPAC preferred method of describing the stereochemistry of double bonds in organic chemistry. It is an extension of cis/trans notation that can be used to describe double bonds having three or four substituents, used to describe molecules having three or four different substituents In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. The terms substituent, side chain, group, branch, or pendant group are used almost interchangeably to describe branches from a parent structure, though certain distinctions are made in the (side groups). For example, of the isomers of butene Butene, also known as butylene, is an alkene with the formula C4H8. It is a colourless gas that is present in crude oil as a minor constituent in quantities that are too small for viable extraction. It is therefore obtained by catalytic cracking of long chain hydrocarbons left during refining of crude oil. Cracking produces a mixture of products, the two methyl groups of (Z)-but-2-ene (aka cis-2-butene) face the same side of the double bond, and in (E)-but2-ene (aka trans-2-butene) the methyl groups face the opposite side. These two isomers of butene are slightly different in their chemical and physical properties.

It is certainly not impossible to twist a double bond. In fact, a 90° twist requires an energy approximately equal to half the strength of a pi bond In chemistry, pi bonds are covalent chemical bonds where two lobes of one involved electron orbital overlap two lobes of the other involved electron orbital. Only one of the orbital's nodal planes passes through both of the involved nuclei. The misalignment of the p orbitals An atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons, in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus. These functions may serve as three-dimensional graph of an electron� is less than expected because pyramidalization In chemistry, trigonal planar is a molecular geometry with one atom at the center and three atoms at the corners of a triangle all in one plane. In an ideal trigonal planar species, all three ligands are identical and all bond angles are 120°. Such species belong to the point group D3h. Molecules where the three ligands are not identical, such as takes place (See: pyramidal alkene). trans-Cyclooctene Cyclooctene is a cycloalkene with an eight-membered ring. It can exist as either the cis- or trans-isomer with the cis-isomer normally being the predominant configuration. Cyclooctene is a smaller cycloalkene in which the cis-isomer is stable at room temperature. Its most stable conformer is shaped like a crown ether with alternating equatorial is a stable strained alkene and the orbital misalignment is only 19° with a dihedral angle In geometry, the angle between two planes is called their dihedral or torsion angle of 137° (normal 120°) and a degree of pyramidalization of 18°. This explains the dipole Dipoles can be characterized by their dipole moment, a vector quantity. For the simple electric dipole given above, the electric dipole moment points from the negative charge towards the positive charge, and has a magnitude equal to the strength of each charge times the separation between the charges. For the current loop, the magnetic dipole moment of 0.8 D The debye is a CGS unit (a non-SI metric unit) of electric dipole moment[note 1] named in honor of the physicist Peter J. W. Debye. It is defined as 1 × 10−18 statcoulomb-centimeter.[note 2] Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10-10 statcoulomb[note 3] ( for this compound (cis-isomer In organic chemistry, cis-trans isomerism or geometric isomerism or configuration isomerism or E-Z isomerism is a form of stereoisomerism describing the orientation of functional groups within a molecule. In general, such isomers contain double bonds, which cannot rotate, but they can also arise from ring structures, wherein the rotation of bonds 0.4 D) where a value of zero is expected.^[3] The trans isomer of cycloheptene Cycloheptene is a 7-membered cycloalkene with a flash point of -6 C°. It is a raw material in organic chemistry and a monomer in polymer synthesis. Cycloheptene can exist as either the cis- or the trans-isomer is only stable at low temperatures.

Alkenes serve as a feedstock for the petrochemical industry because they can participate in a wide variety of reactions.

Addition reactions

Alkenes react in many addition reactions, which occur by opening up the double-bond. Most addition reactions to alkenes follow the mechanism of electrophilic addition

Hydrogenation

Hydrogenation of alkenes produces the corresponding alkanes. The reaction is carried out under pressure in the presence of a metallic catalyst. Common industrial catalysts are based on platinum, nickel or palladium. For laboratory syntheses, Raney nickel (an alloy of nickel and aluminium) is often employed. The simplest example of this reaction is the catalytic hydrogenation of ethylene to yield ethane:

CH₂=CH₂ + H₂ → CH₃-CH₃

Halogenation

In electrophilic halogenation the addition of elemental bromine or chlorine to alkenes yields vicinal dibromo- and dichloroalkanes, respectively. The decoloration of a solution of bromine in water is an analytical test for the presence of alkenes:

CH₂=CH₂ + Br₂ → BrCH₂-CH₂Br

It is also used as a quantitive test of unsaturation, expressed as the bromine number of a single compound or mixture. The reaction works because the high electron density at the double bond causes a temporary shift of electrons in the Br-Br bond causing a temporary induced dipole. This makes the Br closest to the double bond slightly positive and therefore an electrophile.

Hydrohalogenation is the addition of hydrohalic acids such as HCl or HBr to alkenes to yield the corresponding haloalkanes.

CH₃-CH=CH₂ + HBr → CH₃-CHBr-CH₂-H

If the two carbon atoms at the double bond are linked to a different number of hydrogen atoms, the halogen is found preferentially at the carbon with fewer hydrogen substituents (Markovnikov's rule).

Oxidation

Alkenes are oxidized with a large number of oxidizing agents. In the presence of oxygen, alkenes burn with a bright flame to produce carbon dioxide and water. Catalytic oxidation with oxygen or the reaction with percarboxylic acids yields epoxides. Reaction with ozone in ozonolysis leads to the breaking of the double bond, yielding two aldehydes or ketones. Reaction with Concentrated, Hot KMnO₄ (or other oxidizing salts) in an acidic solution will yield ketones or carboxylic acids.

R₁-CH=CH-R₂ + O₃ → R₁-CHO + R₂-CHO + H₂O

This reaction can be used to determine the position of a double bond in an unknown alkene.

Polymerization

Polymerization of alkenes is a reaction that yields polymers of high industrial value at great economy, such as the plastics polyethylene and polypropylene. Polymers from alkene monomers are referred to in a general way as polyolefins or in rare instances as polyalkenes. To be more specific, a polymer from alpha-olefins is called a polyalphaolefin (PAO). Polymerization can proceed via either a free-radical or an ionic mechanism, converting the double to a single bond and forming single bonds to join the other monomers. Polymerization of conjugated dienes such as buta-1,3-diene or isoprene (2-methylbuta-1,3-diene) results in largely 1,4-addition with possibly some 1,2-addition of the diene monomer to a growing polymer chain. For details, see "Polybutadiene".

Reaction overview

Reaction name	Product	Comment
Hydrogenation	alkanes	addition of hydrogen
Halogen addition reaction	1,2-dihalide	electrophilic addition of halogens
Hydrohalogenation	haloalkanes	addition of hydrohalic acids
Hydroamination	amines	addition of N-H bond across C-C double bond
Hydroformylation	aldehydes	industrial process, addition of CO and H₂
Sharpless bishydroxylation	diols	oxidation, reagent: osmium tetroxide , chiral ligand
Woodward cis-hydroxylation	diols	oxidation, reagents: iodine, silver acetate
ozonolysis	aldehydes or ketones	reagent: ozone
Olefin metathesis	alkenes	two alkenes rearrange to form two new alkenes
Diels-Alder reaction	cyclohexenes	cycloaddition with a diene
Pauson-Khand reaction	cyclopentenones	cycloaddition with an alkyne and CO
Hydroboration–oxidation	alcohols	reagents: borane , then a peroxide
oxymercuration-reduction	alcohols	electrophilic addition of mercuric acetate, then reduction
Prins reaction	1,3-diols	electrophilic addition with aldehyde or ketone
Paterno–Büchi reaction	oxetanes	photochemical reaction with aldehyde or ketone
Epoxidation	epoxide	electrophilic addition of an peroxide
Cyclopropanation	cyclopropanes	addition of carbenes or carbenoids
Hydroacylation	ketones	oxidative addition / reductive elimination by metal catalyst

Synthesis

Industrial methods

The most common industrial synthesis of alkenes is based on cracking of petroleum. Large alkanes are broken apart at high temperatures, often in the presence of a zeolite catalyst, to give alkenes and smaller alkanes, and the mixture of products is then separated by fractional distillation. This is mainly used for the manufacture of small alkenes (up to six carbons).^[1]

Related to this is catalytic dehydrogenation, where an alkane loses hydrogen at high temperatures to produce a corresponding alkene. ^[1] This is the reverse of the catalytic hydrogenation of alkenes.

Both of these processes are endothermic, but they are driven towards the alkene at high temperatures by entropy (the TΔS portion of the equation ΔG = ΔH – TΔS dominates for high T).

Catalytic synthesis of higher α-alkenes (of the type RCH=CH₂) can also be achieved by a reaction of ethylene with the organometallic compound triethylaluminium in the presence of nickel, cobalt, or platinum.

Elimination reactions

One of the principal methods for alkene synthesis in the laboratory is the elimination of alkyl halides, alcohols, and similar compounds. Most common is the β-elimination via the E2 or E1 mechanism,^[4] but α-eliminations are also known.

The E2 mechanism provides a more reliable β-elimination method than E1 for most alkene syntheses. Most E2 eliminations start with an alkyl halide or alkyl sulfonate ester (such as a tosylate or triflate). When an alkyl halide is used, the reaction is called a dehydrohalogenation. For unsymmetrical products, the more substituted alkenes (those with fewer hydrogens attached to the C=C) tend to predominate (see Saytzeff's rule). Two common methods of elimination reactions are dehydrohalogenation of alkyl halides and dehydration of alcohols. A typical example is shown below; note that the H that leaves must be anti to the leaving group, even though this leads to the less stable Z-isomer.^[5]

Alkenes can be synthesized from alcohols via dehydration, in which case water is lost via the E1 mechanism. For example, the dehydration of ethanol produces ethene:

CH₃CH₂OH + H₂SO₄ → H₂C=CH₂ + H₃O⁺ + HSO₄⁻

An alcohol may also be converted to a better leaving group (e.g., xanthate), so as to allow a milder syn-elimination such as the Chugaev elimination and the Grieco elimination. Related reactions include eliminations by β-haloethers (the Boord olefin synthesis) and esters (ester pyrolysis).

Alkenes can be prepared indirectly from alkyl amines. The amine or ammonia is not a suitable leaving group, so the amine is first either alkylated (as in the Hofmann elimination) or oxidized to an amine oxide (the Cope reaction) to render a smooth elimination possible. Hofmann elimination is unusual in that the less substituted (non-Saytseff) alkene is usually the major product. The Cope reaction is a syn-elimination that occurs at or below 150 °C, for example:^[6]

Alkenes are generated from α-halo sulfones in the Ramberg-Bäcklund reaction, via a three-membered ring sulfone intermediate.

Synthesis from carbonyl compounds

Another important method for alkene synthesis involves construction of a new carbon-carbon double bond by coupling of a carbonyl compound (such as an aldehyde or ketone) to a carbanion equivalent. Such reactions are sometimes called olefinations. The most well-known of these methods is the Wittig reaction, but other related methods are known.

The Wittig reaction involves reaction of an aldehyde or ketone with a Wittig reagent (or phosphorane) of the type Ph₃P=CHR to produce an alkene and Ph₃P=O. The Wittig reagent is itself prepared easily from triphenylphosphine and an alkyl halide. The reaction is quite general and many functional groups are tolerated, even esters, as in this example:^[7]

Related to the Wittig reaction is the Peterson olefination. This uses a less accessible silicon-based reagent in place of the phosphorane, but it allows for the selection of E or Z products. If an E-product is desired, another alternative is the Julia olefination, which uses the carbanion generated from a phenyl sulfone. The Takai olefination based on an organochromium intermediate also delivers E-products. A titanium compound, Tebbe's reagent, is useful for the synthesis of methylene compounds; in this case, even esters and amides react.

A pair of carbonyl compounds can also be reductively coupled together (with reduction) to generate an alkene. Symmetrical alkenes can be prepared from a single aldehyde or ketone coupling with itself, using Ti metal reduction (the McMurry reaction). If two different ketones are to be coupled, a more complex, indirect method such as the Barton-Kellogg reaction may be used.

A single ketone can also be converted to the corresponding alkene via its tosylhydrazone, using sodium methoxide (the Bamford-Stevens reaction) or an alkyllithium (the Shapiro reaction).

Olefin metathesis

Main article: Olefin metathesis

Alkenes can be prepared by exchange with other alkenes, in a reaction known as olefin metathesis. Frequently, loss of ethene gas is used to drive the reaction towards a desired product. In many cases, a mixture of geometric isomers is obtained, but the reaction tolerates many functional groups. The method is particularly effective for the preparation of cyclic alkenes, as in this synthesis of muscone:

Coupling reactions

Coupling reactions, most notably those catalyzed by palladium compounds, have become popular for the synthesis of alkenes.^[8] The Heck reaction provides a method for coupling an aryl halide to an alkene, for example in the synthesis of the pharmaceutical naproxen:

Other couplings, such as the Stille, Suzuki and Negishi involve the reaction of an alkenyl, allyl or aryl halide (or triflate) with an alkenyl, alkyl (not for Stille) or aryl derivative of a metal or metalloid. For example, Suzuki coupling has been used on a citronellal derivative for the synthesis of caparratriene, a natural product that is highly active against leukemia:^[9]

From alkynes

Reduction of alkynes is a useful method for the stereoselective synthesis of disubstituted alkenes. If the cis-alkene is desired, hydrogenation in the presence of Lindlar's catalyst is commonly used, though hydroboration followed by hydrolysis provides an alternative approach. Reduction of the alkyne by sodium metal in liquid ammonia gives the trans-alkene.^[10]

For the preparation multisubstituted alkenes, carbometalation of alkynes can give rise to a large variety of alkene derivatives.

Rearrangements and related reactions

Alkenes can be synthesized from other alkenes via rearrangement reactions. Besides olefin metathesis (described above), a large number of pericyclic reactions can be used such as the ene reaction and the Cope rearrangement.

In the Diels-Alder reaction, a cyclohexene derivative is prepared from a diene and a reactive or electron-deficient alkene.

Nomenclature

IUPAC Names

To form the root of the IUPAC names for alkenes, simply change the -an- infix of the parent to -en-. For example, CH₃-CH₃ is the alkane ethANe. The name of CH₂=CH₂ is therefore ethENe.

In higher alkenes, where isomers exist that differ in location of the double bond, the following numbering system is used:

Number the longest carbon chain that contains the double bond in the direction that gives the carbon atoms of the double bond the lowest possible numbers.
Indicate the location of the double bond by the location of its first carbon.
Name branched or substituted alkenes in a manner similar to alkanes.
Number the carbon atoms, locate and name substituent groups, locate the double bond, and name the main chain.

Naming substituted hex-1-enes

Cis-Trans notation

Main article: Cis-trans isomerism

In the specific case of disubstituted alkenes where the two carbons have one substituent each, Cis-trans notation may be used. If both substituents are on the same side of the bond, it is defined as (cis-). If the substituents are on either side of the bond, it is defined as (trans-).

The difference between cis- and trans- isomers

E,Z notation

Main article: E-Z notation

When an alkene has more than one substituent (especially necessary with 3 or 4 substituents), the double bond geometry is described using the labels E and Z. These labels come from the German words "entgegen," meaning "opposite," and "zusammen," meaning "together." Alkenes with the higher priority groups (as determined by CIP rules) on the same side of the double bond have these groups together and are designated Z. Alkenes with the higher priority groups on opposite sides are designated E. A mnemonic to remember this: Z notation has the higher priority groups on "ze zame zide."

The difference between E and Z isomers

Groups containing C=C double bonds

IUPAC recognizes two names for hydrocarbon groups containing carbon-carbon double bonds, the vinyl group and the allyl group. .^[2]

References

^ ^a ^b ^c ^d Wade, L.G. (Sixth Ed., 2006). Organic Chemistry. Pearson Prentice Hall. pp. 279.
^ ^a ^b ^c Moss, G. P.; Smith, P. A. S.; Tavernier, D. (1995). "Glossary of Class Names of Organic Compounds and Reactive Intermediates Based on Structure (IUPAC Recommendations 1995)". Pure and Applied Chemistry 67: 1307–1375. doi:10.1351/pac199567081307.
^ Barrows, Susan E. (2005). "Understanding Rotation about a C=C Double Bond". J. Chem. Educ. 82: 1329. doi:10.1021/ed082p1329. http://jchemed.chem.wisc.edu/Journal/Issues/2005/Sep/abs1329.html.
^ Saunders, W. H. (1964). Patai, Saul. ed. The Chemistry of Alkenes. Wiley Interscience. pp. 149–150.
^ Cram, D.J.; Greene, Frederick D.; Depuy, C. H. (1956). "Studies in Stereochemistry. XXV. Eclipsing Effects in the E2 Reaction1". Journal of the American Chemical Society 78 (4): 790–796. doi:10.1021/ja01585a024.
^ Bach, R.D.; Andrzejewski, Denis; Dusold, Laurence R. (1973). "Mechanism of the Cope elimination". J. Org. Chem. 38: 1742–3. doi:10.1021/jo00949a029.
^ Snider, Barry B.; Matsuo, Y; Snider, BB (2006). "Synthesis of ent-Thallusin". Org. Lett. 8 (10): 2123–6. doi:10.1021/ol0605777. PMID 16671797.
^ Zweifel, George S.; Nantz, Michael H. (2007). Modern Organic Synthesis: An Introduction. New York: W. H. Freeman & Co.. pp. 322–339.
^ Vyvyan, J.R. (1999). "An expedient total synthesis of (+/-)-caparratriene". Tetrahedron Letters 40 (27): 4947–4949. doi:10.1016/S0040-4039(99)00865-5. http://linkinghub.elsevier.com/retrieve/pii/S0040403999008655. Retrieved 2008-01-02.
^ Zweifel, George S.; Nantz, Michael H. (2007). Modern Organic Synthesis: An Introduction. New York: W. H. Freeman & Co.. pp. 366.

Alkenes

Ethene ( C₂H₄ ) • Propene ( C₃H₆ ) • Butene ( C₄H₈ ) • Pentene ( C₅H₁₀ ) • Hexene ( C₆H₁₂ )

Functional groups

Alcohol · Aldehyde · Alkane · Alkene · Alkyne · Amide · Amine · Azo compound · Benzene derivative · Carboxylic acid · Cyanate · Disulfide · Ester · Ether · Haloalkane · Hydrazone · Imine · Isocyanide · Isocyanate · Ketone · Organophosphorus · Oxime · Nitrile · Nitro compound · Nitroso compound · Peroxide · Phosphonous and Phosphonic acid · Pyridine derivative · Sulfone · Sulfonic acid · Sulfoxide · Thioester · Thioether · Thiol

See also Chemical classification

Chemistry

Analytical chemistry · Biochemistry · Bioinorganic chemistry · Bioorganic chemistry · Biophysical chemistry · Chemical biology · Chemical physics · Chemistry education · Click chemistry · Cluster chemistry · Computational chemistry · Electrochemistry · Environmental chemistry · Green chemistry · Inorganic chemistry · Materials science · Medicinal chemistry · Nuclear chemistry · Organic chemistry · Organometallic chemistry · Pharmacy · Physical chemistry · Photochemistry · Polymer chemistry · Solid-state chemistry · Supramolecular chemistry · Theoretical chemistry · Thermochemistry · Wet chemistry

List of biomolecules · List of inorganic compounds · List of organic compounds · Periodic table

Categories: Alkenes | Functional groups | Organic compounds

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The Journal of Organic Chemistry, Volume 75, Issue 5, Page 1771-1774, March 2010.

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Wed Mar 17 17:31:48 2010

'Alkenes' Answers

In terms of intermolecular forces why do alcohols have higher boiling points than alkenes?
Q. Is this to do with the branching in alkenes?
Asked by laurrrrrr! - Mon Apr 19 12:54:15 2010 - - 1 Answers - 0 Comments

A. alcohols has a Hydrogen bonds, alkenes has no hydrogen bond. This cause the intermolecular forces of alcohols is stronger than alkenes. Alcohols have higher boiling points than alkenes. sorry for my bad english
Answered by Mukti - Mon Apr 19 13:02:58 2010

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Sun Jul 18 10:16:43 2010

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