Organic Chemistry

Enantiomer

Another name for optical isomer. Amino acids and sugars.

Green chemistry

Approach that focuses on designing synthetic processes so that they're sustainable and don't have a negative impact on the environment and society through production of toxic substances. 12 priciples of green chemistry: 1. Prevent waste. 2. Use renewable feedstock. 3. Atom economy. 4. Reduce derivatives. 5. Less hazardous waste. 6. Catalysts. 7. Design benign chemicals. 8. Design for degradation. 9. Benign solvents and auxiliaries. 10. Real-time analysis for pollution prevention. 11. Design for energy efficiency. 12. Inherently benign chemistry for accident prevention.

What would the fastest nucleophilic substitution reaction use?

Aprotic solvent like ether or ketone, iodine, and primary halogenoalkane.

Amides

Are weak bases. One amido attached. Functional group: —CONH2. (O is double bonded to C.) General formula: R—CONH2. Naming rules: name longest hydrocarbon chain. Drop "e" and add suffix -amide.

Amines

Are weak bases. One amino attached. Functional group: —NH (w/two extra bonds open), —NH2 (w/one bond open), —N (w/three bonds open). General formula: R—NH—R', R—NH2, R—N—R'—R''. Naming rules: name each alkyl group and add suffix -amine.

Nitriles

Are weak bases. One cyano attached. Functional group: —C///N. (That's a triple bond to the N.) General formula: R—C///N. Naming rules: name longest hydrocarbon chain and add suffix -nitrile.

Structural diagrams

Can be full, which shows every carbon, hydrogen, etc. and every bond. Can be condensed, showing all atoms and some bonds. Can be more condensed, showing only atoms and no bonds. You have to be able to see the double bonds etc. that aren't written in the super condensed version. It's helpful to take the condensed formula and draw it out to something more expanded so you can determine what kinds of reactions will be going on.

Physical properties of a homologous series

Change gradually as length of carbon chain increases. Ex: bpt increases with increasing number of C atoms/increasing molar mass. Shown since butane is gas at room temperature and pentane is a liquid. Results from increasingly strong IMF as C chain gets longer. There are also trends in increasing density and viscosity with increasing C chain length. This is important for the petrochemical industry, as crude oil is a mix of hydrocarbons that vary in the length of the C chain.

Structural isomers

Change locations in compound of atom/group/bond. Must use distillation to separate them. Very common. React very similarly, the difference is the melting and boiling point, which is used for distillation. The melting and boiling point thing is a result of surface area and intermolecular forces.

Most naturally occurring hydrocarbons come from...

Crude oil, which is extracted from beneath Earth's surface, refined, and separated by fractional distillation into useful substances. The mixture of hydrocarbons in crude oil is mainly alkanes, cycloalkanes, and aromatic hydrocarbons.

What kind of arrows show movement of electrons?

Curly arrows

Conformational isomerism in cyclic hydrocarbons

Cycloalkanes also show conformational isomerism; they have structural consequences from the bond angles in C3, C4, and C5 cycloalkanes that have been extensively researched.

Esters description

Derived from carboxylic acids and have a variety of applications ranging from flavoring agents and medications to solvents and explosives. Esterification is a reversible reaction that occurs when a carboxylic acid and an alcohol are heated in the presence of a catalyst, normally concentrated sulfuric acid.

Diastereomers

Different from the enantiomers of optical isomers. They're non-superimposable but don't form mirror images. Have two or more stereo centers and differ in the configuration of at least one center. Diastereoisomers with the same general formula have different physical and chemical properties. More than one hydrocarbon. Can have problems when making things artificially—many options.

Serendipity

Fortunate accidental discoveries within science.

Alkynes

Functional group: C///C. Triple bond between at least two carbons. CnH2n-2.

Alkenes

Functional group: C=C. Double bond between at least two carbons. CnH2n. Presence of double bond makes them more reactive than corresponding saturated alkanes.

Alkanes

Functional group: C—C. Single bond between (at least) 2 carbons. CnH2n+2.

Intermolecular forces for organic compounds

Hydrocarbons have London dispersion only. Anything that has anything other than H and C only at least has dipole-dipole (so things like esters/ethers/halogenoalkanes/nitriles). Some have hydrogen bonding (alcohols, organic acids, amines, amides—the functional groups have either oxygen or nitrogen). Hydrogen bonding is how DNA stays together.

Mass spectrometry

(MS). When a gaseous molecule is ionized, its molecular ion M1+ is formed. The molecular ion peak in a mass spectrum corresponds to the molecular mass of the compound. Because of highly energetic ionization process in the mass spectrometer, molecule can break up into smaller fragments, some of which are ions. Fragmentation pattern in mass spectrum provides further info on certain functional groups are present in a molecule. Spec printout is relative abundance on the y axis and m/z (with z being charge) on the x axis. Single lines print out.

Primary compound

1 other carbon is attached to the carbon with the functional group (or for amines, 1 carbon attached to nitrogen)

Naming for hydrocarbons

1. Find the longest carbon chain with multiple bonds (2x or 3x) and name it. 2. Number the carbons...double or triple bonded gets the lowest number. 3. Number and name the alkyl attachments. If they are rings, uses the prefix "cyclo."

Structural formulae

3 forms: 1. Full structural formulae—2-D representations showing all atoms and their bonds, and their positions relative to one another in a compound. 2. Condensed structural formula—all the atoms and their relative positions are represented, but bonds are omitted. 3. Skeletal formula—most basic representation of structural formula where the C and H atoms aren't shown, but the end of each line and each vertex represents a C atom; atoms present in functional groups are shown.

Tertiary compound

3 other carbons are attached to the carbon with the functional group (or for amines, 3 carbons attached to nitrogen)

esterification reaction

A condensation reaction in which a carboxylic acid and an alcohol combine to produce an ester and water.

Free-radical

A species formed when a molecule undergoes homolytic fission. The two electrons of the covalent bond are split evenly between 2 atoms, resulting in 2 free-radicals, each with a single electron. Radicals are extremely unstable and will attack all of the other compounds around them. They are in an unsustainable state, and they want to pair up.

SN2 Reactions

In a "backside attack" the nucleophile attacks the electrophilic center at 180° to the large halogen atom, creating steric hindrance (hindrance by bulky substituents that prevents "frontal attack" by a nucleophile). As this rxn proceeds, the entering nucleophile causes an inversion of configuration known as the Walden inversion. Therefore, the SN2 reaction is stereospecific (a rxn where starting reagents differing only in their configuration are converted into stereoisomeric products). Forms a transition state that can never be isolated/not viable. The atoms attached to the C can move and make space for something else to come in, since H is tiny.

Ethane (isomer discussion)

In everything, rotation about the carbon carbon bond results in two different confirmations, eclipsed and staggered. The eclipsed confirmation has the substituents on adjacent carbon Adams as close to one another as possible. The staggered confirmation is 1/2 of the molecule rotates about the carbon carbon bond, the relative positions at the substituents change until the three hydrogen atoms on each carbon as far apart as possible.

Electrophilic addition of hydrogen halides to alkenes

In rxn btwn but-1-ene and HI, the major product is 2-iodobutane, as the 2° carbocation is formed preferentially. HI is split heterolytically into H1+ and I1-. Initial attack on pi electrons of carbon carbon double bond comes from cation, followed by rapid rxn btwn unstable carbocation and halogen ion.

Refluxing

A technique that involves the cyclic evaporation and condensation of a volatile reaction mixture, preserving the solvent as it does not evaporate

Optical isomerism

A type of configurational isomerism determined by the presence of chiral carbon atoms. These are carbon atoms that are bonded to four different atoms or groups of atoms, also known as the stereocenter or asymmetric center. Optical isomers can rotate plane-polarized light and exist in pairs called enantiomers or diastereoisomers. These are non-superimposable mirror images of each other. They have no plane of symmetry, and their optical activity is most readily assigned when the molecules are represented as 3-D images.

Ethene and ripening fruit

Accelerates ripening of fruit while preventing build-up of ethene around fruit by introducing CO2 to the container, which slows the rate of ripening

Test for unsaturation

Add bromine water, Br2 (aq). A mix of an alkene and bromine water will undergo a color change from light brown to colorless. Double bond opens up, and one bromine is added to each C that used to have the double bond. If there is no color change, it's a negative result, indicating the absence of a C=C (or a C///C for that matter).

Reactivity of primary vs. secondary vs. tertiary compounds

It's easier for primary to undergo reactions and harder for secondary and tertiary.

What do you absolutely need to know about an organic compound?

Its name and structural formula. The chemical formula can be helpful, but you might not need it.

Carotenoids

Large group of organic pigments that display a wide range of stereo chemical properties. Research into affects of carotenoids and visual and motor integration within human body focuses on individual stereoisomers in isolation from their isomeric partners. Visual motor integration measures a child's ability to make a sense of visual info and then use it appropriately for a motor task.

Naming for aromatic hydrocarbons.

Like benzene. Add prefix for any alkyl groups, for example, propylbenzene, if the benzene is the only structure with multiple bonds. However, if there's a double bond or something in the attachment, name that and add the prefix phenyl with the number of whatever carbon it's on. Also, don't forget that you number where the double or triple bond is!

Isomers with biological compounds

Lipids have the cis-trans set-up. Amino acids have the optical isomer set-up. Carbohydrates and sugars in nucleic acids have optical.

Name the alkyl substituents. How do you order the names of the substituents of there are multiple? How do you separate numbers and letters? How do you separate multiple numbers? How do you indicate multiple of one substituent?

Methyl, ethyl, propyl, butyl, pentyl, hexyl. Alphabetical order if there are multiple in a compound. Numbers and letters are separated by hyphens. Numbers are separated by commas. Indicate multiple of one substituent with prefix: mono, di, tri, tetra, penta.

Research Octane Number (RON)

Most common method of determining the octane number, though the motor octane number (MON) is also used, either alone or in combination with the RON. Method varies country to country.

Nucleophilic

Negative looking for something positive. Electron-rich species capable of donating a pair of electrons to an electrophile to create a covalent bond. Strength depends on ease with which it can make these electrons available. Negatively charged ions are better nucleophiles than neutral molecules, although neutral molecules w/at least one electron pair like water can be nucleophiles.

Net exporters vs. net importers of crude oil

Net exporters produce more barrels of crude oil than they consume, whereas net importers consume more barrels than they produce.

Conversion of nitrobenzene to phenylamine (aniline)

Nitration of benzene by electrophilic addition occurs when benzene is heated at 50°C with a mixture of sulfuric acid and nitric acid. The subsequent conversion of nitrobenzene to phenylamine has two stages. Stage one is the reduction of nitrobenzene. Nitrobenzene is heated in water bath under reflux with a mix of zinc and concentrated hydrochloric acid. It forms the phenylammonium ion and zinc is oxidized to Zn2+. Stage two is the formation of aniline. Aniline (C6H5NH2) is formed by the deprotonation of the ammonium salt through the addition of sodium hydroxide.

Nucleophile options for nucleophilic substitution reactions

OH 1- for an alcohol, NH2 1- for an amine, CN 1- for a nitrile

Oxidation of primary alcohols

Oxidation of a primary alcohol is a two stage process that first produces an aldehyde, followed by a carboxylic acid. Must be heated with K2CrO7 or KMnO4. The aldehyde formed can be further oxidized to a carboxylic acid. The aldehyde can be recovered by the process of distillation, since it has a lower bpt than the carboxylic acid (which has hydrogen bonding), preventing its further oxidation. If the carboxylic acid is the desired product, the aldehyde must remain in the mixture for a longer period of time, so a reflux column is used. Breathalyzers pick up on aldehydes.

Oxidation of secondary alcohols

Oxidation of a secondary alcohol results in formation of a ketone. No further oxidation is possible, as carbon atom of functional group has no H's attached to it.

Fractional distillation

Physical separation process that uses differences in bpts to separate mixture into fractions of similar bpt. Can separate volatile fractions from long-chain, non-volatile compounds.

Aprotic solvents

Polar but don't have hydrogens. Ketones, ethers, aldehydes. Faster because they don't have hydrogens to surround the negative nucleophile, so aprotic increases rate.

PTFE

Polytetrafluoroethylene. Synthetic polymer called Teflon. It's a thermoplastic polymer, meaning that it can be molded when heated, retaining a new shape upon cooling. Has a high chemical resistance, low coefficient of friction, high mpt, electrical and thermal insulation, non-stick surface qualities, very low solubility in all known solvents. Accidentally discovered in 1938, a product of the iron-catalyzed polymerization of tetrafluoroethene gas. Serendipity.

Electrophilic

Positive looking for something negative. Electron-deficient species that will accept a pair of electrons, acting as a Lewis acid. Have either a formal positive charge or a partial positive charge generated by presence of a highly electronegative species, resulting in polarization of the bond.

Catenation

Process by which many identical atoms are joined together by covalent bonds, producing straight-chain, branched, or cyclic structures. Ability of an atom to bond to itself over and over and over again—no limit. Can form chains, branched chains, or rings.

Reflux

Process in which a reaction mixture is heated under controlled conditions for a period of time. Condenser is used to cool the vapors from volatile solvents and condense them back into the reaction mixture. This process ensures that the temperature remains constant over time, and optimal conditions for the reaction are achieved.

What does the position of the hydroxyl group in an alcohol determined?

Products formed when the alcohol undergoes oxdn in presence of acidified potassium dichromate (VI) or potassium manganate (VII).

Synthetic compounds

Products of reactions involving both natural and man-made compounds

E/Z System

Relative priorities are assigned to the substituents of each carbon on the carbon carbon double bond. Cahn-Ingold-Prelog (CIP) system rules for assigning the stereo chemistry of substitued Alkenes can be used to assign R or S configuration to each stereocenter and E or Z to a double bond. Cis is Z and trans is E. Steps to assign E or Z configuration: 1. Get priority of each atom bonded to carbon of carbon carbon double bond by ordering Adams from highest to lowest atomic number. 2. If both higher priority substituents are on the same side of the double bond, it is a Z isomer. If they're on opposite sides, it's an E isomer.

Elimination reaction

Removal of 2 substituents from the molecule.

Substitution reaction

Replacement of individual atoms with other single atoms or with a small group of atoms

empirical formula

Represent the simplest ratio of atoms present in a molecule. Doesn't give info about structure.

Cyclopropane

Ring structure of cyclopropane lacks stability as the molecule experiences ring strain for two reasons. Exhibit torsional strain from repulsion of adjacent bonding electrons in carbon hydrogen bonds due to ring rigidity. Exhibit angle strain. The SP3 orbital angle is 109.5°(tetrahedral) but the internuclear bond angle in cyclopropane is only 60°, resulting in a misalignment of the orbitals when they overlap on end to create the sigma bond. The result is a bent carbon carbon bond, confirmed by electron density mapping

Cycloalkanes

Ring structures that contain single carbon-carbon bonds

Homologous series

Same general compound formula, but each consecutive compound changes by 1 C, 2 H. (A —CH2 group.) ex: methane, ethane, propane, butane, ... Can be grouped together based on similarities in their structure and reactions. The alkanes, alkenes, and alkynes are all homologous series. Homologous series that contain functional groups can also be described by a general formula and still show similar chemical and physical properties within the series.

Propagation

Second stage of free-radical substitution. Propagation 1 involves a reaction between the alkane and the radical—a hydrogen from the organic compound joins with the radical, and now the organic compound has been turned into a radical. This allows the reaction to continue, as a chain reaction is set up. The new radical pulls a halogen/an atom from a diatomic molecule and joins with it, making the other part of the diatomic molecule a new radical. Keeps happening as long as energy source is present and have enough org compd.

Octane number

Standard method of describing the performance of fuels used in cars and aircraft. Not indicative of energy content in fuel. Way to describe its ability to combust in a controlled manner w/o causing excessive engine knocking (result of uncontrolled detonation of the air-fuel mixture in combustion mixture which is more common in fuels with a low octane number)

aliphatic compounds

Straight chain compounds, for example, alkanes.

Melting and boiling points for straight vs. branched chains

Straight have more surface area and thus a higher boiling point, whereas branched have less surface area and a lower boiling points. Due to intermolecular forces—hydrocarbons are nonpolar covalent and only have London dispersion forces. Branching decreases the surface area available to establish London dispersion forces, so branched chains have lower boiling points.

Pharmacodynamics

Studies action of drug on systems of body and how a drug binds to its target site.

Pharmacokinetics

Studies the body's response to form compounds and changes caused by the administered drug. Associated with absorption, distribution, metabolism, and excretion of drug by body.

Spectroscopy

Study of the way matter interacts with radiation. Various regions of the electromagnetic spectrum are the bases of different types of spectroscopy, and various techniques are used to identify substances' structures. Since x-rays have high energy, because electrons to be removed from inner energy levels of atoms. Diffraction patterns can lead to information like bond distances and angles in a structure and form the basis of x-ray crystallography. Visible and ultraviolet light cause electronic transitions and give information about the electronic energy levels in an atom or molecule. They are the basis of UV-vis spectroscopy. Infrared radiation causes certain bonds in a molecule to vibrate (stretch and bend) and therefore provide information on functional groups present. Basis of IR spectroscopy. Microwaves cause molecular rotations and can give info on bond lengths. Radio waves can cause nuclear transitions in strong magnetic field because can be absorbed by certain nuclei, causing their spin states to change. Basis of nuclear magnetic resonance spectroscopy. Can be deduced what the atoms' chemical environments are, leading to information on connectivity of atoms in a molecule. Main types of spectroscopy are infrared, proton nuclear magnetic resonance, and mass spectrometry.

Classes of organic compounds

Synthetic and natural compounds are organized into classes of organic compounds containing specific functional groups.

SN1 Reactions

Tertiary halogenoalkanes. 2 steps. The rate-determining step involves only the halogenoalkane: the bond to the leaving group breaks, forming a carbocation. In the second step, the fast one, the nucleophile bonds to the carbocation. First-order reaction. Rate = k[halogenoalkane]. Molecularity of one because 1 molecular entity is involved in the elementary reaction (unimolecular). The carbocation is the intermediate. The intermediate actually exists for a finite time, and we can't extract it or stop the rxn, but it's there.

Functional groups

The reactive parts of the molecules; commonly contain elements like O and N.

What is R?

The rest of the compound—a bunch of carbons and hydrogens, can be complex or simple.

Physical and chemical properties of optical isomers

Two enantiomers of a particular substance have identical physical properties, like boiling point and melting point, viscosity, density, and solubility. Many chemical properties are also identical except their reactions with other optical isomers, often in biological systems. Enzymes within the body are chiral and can distinguish between the enantiomers of their substrate. Tertogen is one enantiomer of the drug thalidomide, which was the enantiomer that caused birth defects in babies born to some mothers who took the drug.

Addition reaction

Two molecules are added together to produce a single molecule. Cannot be undergone by alkanes. Open up a double or triple bond.

Racemic mixture

When we artificially try to create an iceberg, we can't get 100% of one like we could biologically. We can separate them using polarized light. The instrumentation essentially bases it off the spinning. Optical isomers have similar physical properties but can't have very different chemical properties, and some people can't biologically process certain optical isomers.

condensation polymerization

When you combine things and get water along with the polymer. In addition polymerization, in contrast, you only get the polymer as the product.

natural compounds

found in plants and animals, synthesized by organisms

Hybridization and VSEPR for triple bonds

sp, linear, 2 sigmas and 2 pis

Hybridization and VSEPR for double bonds

sp2, trigonal planar, 3 sigmas and a pi

Hybridization and VSEPR for single bonds

sp3, tetrahedral, 4 sigma bonds

Biofuels

substances whose energy is derived from carbon fixation in plants. Alcohols and other biofuels are increasingly used as alternative fuels to gasoline and diesel. Fossil fuels remain the primary energy source on a global scale, but the complex mixture that makes up crude oil can be used for synthesis of various products. The ever-increasing combustion of valuable non-renewable fossil fuels could result in their depletion and that of raw materials for substances we use in daily lives.

When you halogenate alkanes/alkenes/alkynes, what happens to their IMF?

they start as nonpolar and not water soluble, but halogenation makes them have a tiny polar section, so they can have dipole-dipole IMF. Their physical properties change, as they have higher mpts/bpts and are more soluble in water (can somewhat dissolve). Water solubility increases the more halogens you add.

Factors affecting the rate of nucleophilic substitution

1. Identity of the halogen. Larger halogen is easier to break off, bc bond energy of larger halogen attached to C is lower. Presence of a good leaving group in reactant increases rate of rxn of both SN1 and SN2 mechanisms. In both cases, the RDS involves the heterolytic fission of the carbin-halogen bond, in which the two bonding electrons move to the more electronegative atom. The quicker this is completed, the higher the rate of reaction. A better leaving group will help achieve this. Bond strength and electronegativity are important in choosing a leaving group. Fluoroalkanes are virtually inert due to short length and high strength of C-F bond. As you move down the halogen group, strength decreases as size increases, resulting in longer, weaker bonds. Stability of halogen anion formed during these reactions is directly related to its effectiveness as a leaving group. For ex, the I atom can better dissipate charge than the smaller Cl and F atoms, so it is a better leaving group than them. 2. Class of halogenoalkane (primary/secondary/tertiary). Class of halogenoalkane has direct effect on rate of formation of carbocation (RDS) and therefore the overall rate of a reaction. Tertiary has greater stability than primary. More attachments means more stable, and more stable is slower. In terms of stability: tertiary>secondary>primary, so primary goes fastest. 3. Choice of solvent. You can't have ions unless they have a solvent to be in. SN2 rxns are best performed in aprotic, polar solvents because they have no O-H or N-H groups, so they can't form a H-bond to the nucleophile, and they can't solvate the nucleophile. They thus leave it "naked" and it maintains its effectiveness as a nucleophile in forming the transition state. Ethylethanoate and propanone are aprotic solvents. SN1 reactions are best in protic, polar solvents because they are polar due to presence of polar bonds and have either an O-H or an N-H group, so they can form bonds with the nucleophile. They solvate the nucleophile, thus inhibiting its ability to attack electrophiles like the partially positively charged carbon atom. Methanol, water, ammonia, methanoic acid, and hydrogen fluoride are protic solvents.

What is the benefit of putting organic compounds into homologous series?

1. You know they have the same functional group and similar properties. 2. As we add a carbon and 2 H, you are adding mass and increasing melting and boiling points. These different melting and boiling points are crucial for separation via distillation. (Other type of separation is called extraction.) When you remove C's and H's, you decrease the melting and boiling points.

Secondary compound

2 other carbons are attached to the carbon with the functional group (or for amines, 2 carbons attached to nitrogen)

How many types of nucleophilic substitution are there? How do you determine the type?

2 types. Reaction mechanism depends on whether the halogenoalkane is primary, secondary, or tertiary. Inductive effects in organic compounds have significant effect on which nucleophilic substitution mechanism occurs btwn a nucleophile and a halogenoalkane. Most important factor is differences in electronegativity btwn atoms present in a molecule. In the C-H bond, C is slightly more electronegative than H, creating weak dipole and a shift in the position of the bonding electrons closer to the carbon atom. Other atoms (like more electronegative halogens) have far greater polarizing effects on the sigma bond. Alkyl groups bonded to a carbocation have a positive inductive effect, stabilizing the charged carbocation by donating electron density and decreasing the positive charge on the carbon atom. A primary carbocation has only one alkyl group contributing to the inductive effect, so it receives the least stabilization. Tertiary carbocation is bonded to three alkyl groups, so will be more stable. This is one reason why tertiary halogenoalkanes tend to undergo reactions via the SN1 mechanism.

What kinds of reactions do alkenes undergo?

Addition reactions, like hydrogenation and addition polymerization. Large quantities of ethene are used in the chemical industry, and it is the product of thermal decomposition or catalytic cracking of a long-chain hydrocarbon. It's an important raw material in the production of organic polymers. With finely divided Ni as a catalyst and heat, ethene can undergo an addition reaction with hydrogen gas to form ethane. This type of reaction is imp in food industry. The addition of H to unsaturated fats and oils occurs in the manufacture of margarine. Removing the double bonds increases the melting point, making the substance a solid at room temp. However, saturated fats and oils in diet increase blood concentration of low-density lipoproteins (LDLs) which are involved in transport of cholesterol in blood. Partial hydrogenation also results in conversion of cis-carbon-carbon double bonds to trans-carbon-carbon double bonds. Trans fats are dangerous, and legislation exists to decrease their use. Alkenes can also undergo electrophilic halogenation, which involves the addition of elemental halogens (diatomic), resulting in a dihalogenated alkane. The addition of a hydrogen halide to a symmetrical alkene results in a single mono-halogenated alkane. Can also add steam (high temp water) to them in an acidic environment to produce alcohols. Addition polymerization is another option, which is a reaction of many small monomers that contain a carbon-carbon double bond linking together to form a polymer. Any monomer that contains a C=C can undergo polymerization. The repeating structural unit of the polymer reflects the structure of the monomer that formed it, with the double bond being replaced by a single bond, and the electrons released forming new bonds to the adjacent monomers. The attachments happen one at a time, not all at once.

Halogenoalkanes description/formation

Alkanes undergo free-radical substitution reactions with halogens, and the resulting mono-substituted alkanes are known as halogenoalkanes. Whether primary, secondary, or tertiary are formed depends on conditions and mechanism of the reaction.

What reactions do alkanes undergo?

Alkanes, the simplest hydrocarbons, have low bond polarity and strong covalent C-C and C-H bonds, so they are relatively inert, but they do undergo some important reactions. Compounds want single bonding, because they want their electrons to be exclusively theirs. The main one is the combustion of alkanes that releases large amounts of energy, as alkanes are commonly used as fuels. Volatility decreases as the length of the alkane increases, so fuels tend to be short-chain molecules like butane and octane. Alkanes undergo complete combustion in the presence of excess O—this is a highly exothermic rxn producing CO2 and H2O. When O supply is limited, alkanes undergo incomplete combustion, producing H2O (steam) and CO, which is poisonous. CO irreversibly binds to hemoglobin in blood, thus reducing its oxygen-carrying capacity. Alkanes can also undergo free-radical substitution and elimination to form unsaturated alkenes and alkynes. Substitution reactions involve first removing something and then adding something else on. This adding part takes energy, and usually, the energy change btwn beginning and end for the alkane is minimal, so substitution reactions with alkanes don't happen very easily or often.

What are the functional groups in the alkene and alkyne homologous series?

Alkene is the C=C, alkyne is the C///C.

Electrophilic addition reactions

Alkenes contain electron rich carbon carbon double bonds and undergo addition reactions in which the double bond breaks and two additional atoms bond with the molecule, creating a saturated compound. The electrophile can act as a source of the new additional atoms. The carbon carbon double bond contains both a sigma bond and a pi bond. The sigma is formed by the end to end overlap of atomic orbitals, and electron density is centered between the nuclei of the bonding atoms, along the inter-nuclear axis. The pi bond is formed by sideways overlap of atomic orbitals, and electron density is found above and below the plane of the bonding atoms' nuclei. With SP2 hybridization in carbon atoms and bond angle of approximately 120°, the carbon carbon double bond provides a reduced level of steric hindrance to the attacking electrophile. A double bond is stronger than a single bond in terms of bond dissociation energy, but the high density of electrons in a double bond means that it's more susceptible to electrophilic attack.

What kind of environments do you need for reactions? (Generally)

All reactions require some heat. You also need a specific environment. If you have negative, no hydrogen. If hydrogen is coming off, it needs to be acidic. If it needs hydrogen to proceed, it also needs to be acidic. Sometimes you need a potassium oxidizing agent. Potassium is good because it doesn't tend to interfere.

Saturated compounds

All single bonds between carbons. Alkanes.

Aromatic hydrocarbons

Also called arenes. Ring structures consisting of alternating single and double carbon-carbon bonds.

Carboxylic acids

Also called organic acids. Are weak acids. One or more carboxyl attached. Functional group: —COOH. (One O is double bonded to the carbon.) General formula: R—COOH. Naming rules: name longest hydrocarbon chain (including C in carboxyl group), drop "e" and add suffix -oic acid. (Keep "e" for 2, -dioic acid, 3, -trioic acid.) Number to lowest carbon (only if more than one group).

Electrophilic substitution reactions

Benzene prefers substitution reactions to addition reactions. Electrophilic substitution mechanism can be illustrated by the nitration of benzene. First, the nitronium ion electric file must be generated. Pure nitric acid contains only a small concentration of it, but a nitrating mixture of sulfuric acid and nitric acid at 50°C generates a higher concentration, allowing the reaction to proceed at an acceptable rate. Sulfuric acid protonates nitric acid, which subsequently releases a water molecule to generate an electrophile. The nitronium ion is a strong electrophile, and as it approaches the delocalized pi electrons of the benzene ring, it is attracted to the ring. Two electrons from the ring are donated and form a new carbon nitrogen bond. A pi electron from the nitrogen oxygen double bond of the nitronium ion moves onto the oxygen atom. This is the RDS. The addition of the ion to the carbon carbon double bond eliminates aromaticity of the arene. Water then acts as a base, deprotonating the carbocation intermediate and restoring the aromaticity of the system. The product is nitrobenzene, a yellow oil that can be isolated from the rxn mixture. The slow step is opening the double bond. The cation comes on, the hydrogen is pushed off, amd the hydrogen joins with the leftover anion. Types can include: halogenation, nitration, sulfonation, hydroxylation, alkylation, and acylation.

Homolytic fission

Breaking a bond to produce two particles that both have a single unpaired electron, a radical.

Confirmational isomers

Can be interconverted by rotation about the sigma bond, without breaking any bonds. Substituents and functional groups are joined by saying single sigma bonds which can rotate freely, changing the 3-D arrangement of the atoms relative to one another. In contrast a carbon carbon double bond is composed of a sigma and a pi bond, and the arrangement of electron density above and below the inter-nuclear access means that rotation is not possible without breaking the pi bond. Therefore, conformational isomers differ from one another in the arrangement of atoms around a single bond. Rapid interconversion from one conformer to another means the separation of the individual isomers is virtually impossible. Bond is always moving, so sometimes one atom ends up in front of another. You can't isolate it though, it's not viable.

Markovnikov's Rule

Can be used to Predict major products of the electrophilic addition of hydrogen halides to unsymmetrical Alkenes. The hydrogen atom will preferentially bond to the carbon atom of the alkene that is already bonded to the largest number of hydrogen substituents. Occurs because the carbocation formed when the pi bond is broken has its positive charge centered on the most substituted carbon. A tertiary carbocation has more stability than a primary carbocation due to the reduction in density of the positive charge through the inductive affects of the three alkyl substituents.

Degree of unsaturation or index of hydrogen deficiency (IHD)

Can be used to determine the number of rings or multiple bands in a molecule from the regular form. A double bond has one degree of unsaturation. I triple bond is 2° of unsaturation. A ring is 1° of unsaturation. An aromatic rain is 4° of unsaturation. Can be worked out from the structure or the molecular formula. IHD = (0.5)(2c + 2 - h - x +n). You get the number, and then you have options as to what the molecule may contain.

Single crystal X-ray crystallography

Can be used to identify the bond lengths and bond angles of crystalline compounds.

Separation of ennatiomers

Can often be very expensive process, so drugs with enantiomers are often administered as racemic mixtures rather than as pure active enantiomer, which can have negative affects on body or on drug action.

configurational isomers

Can only be interconverted by the breaking of the sigma or pi bond or through rearrangement of the stereocenters, like for aliphatic alkenes. Subdivided into cis-trans and E/Z isomers on one hand and optical isomers on the other. These are viable.

High-resolution 1H NMR spectrum

Can show further splitting of some absorptions. Splitting patterns result from spin-spin coupling. Spin spin coupling is transmitted through the electrons in the individual bonds. Therefore it depends on the way the hydrogens are related to each other in the bonding arrangements within the molecule. Rules: 1. If a proton, Ha, has n protons as its nearest neighbors, that is n x Hb, then the peak of Ha will split into (n+1) peaks. 2. The ratio of the intensities of the lines of the split peak can be deduced from Pascal's triangle.

Oxidation of a tertiary alcohol

Cannot occur!

Carbon electrons

Carbon has 4 valence electrons, so it can make bonds with four other atoms

Cyclobutane

Carbon ring bond angle increases from 60° in cyclopropane to 90° in cyclobutane. Molecule of cyclobutane still experiences angle strain and torsional strain from eclipsed arrangement of adjacent carbon hydrogen bonds. One way of minimizing string placed on this conformer is to pack her the ring. One of four carbon atoms moves out of the plane of the ring, slightly increasing angle stream but significantly decreasing torsional strain.

Reduction of carboxylic acids

Carboxylic acids are reduced to aldehydes and eventually to primary alcohols. Ketones are reduced to secondary alcohols. These reactions are the reverse of the oxidation of alcohols. Commonly used reducing agents are lithium aluminum hydride (LiAlH4) and sodium borohydride (NaBH4). Lithium aluminum hydride is a nucleophilic reducing agent that will reduce polar carbon oxygen double bonds in carboxylic acids, aldehydes, and ketones. Stronger reducing agent than sodium borohydride. It can reduce carboxylic acids to primary alcohols, while sodium borohydride can reduce only aldehydes and ketones to alcohols.

List carbon's properties that enable organic chemistry

Catenation, single/double/triple bonds are possible, can bond to other nonmetals (all except noble gases, I believe).

Aromatic hydrocarbons

Characterized by the presence of the benzene ring. C6H6, with alternating double and single bonds. X-ray crystallography showed that the bond lengths end up all being the same, so benzene has a bond order of 1.5. Benzene contains 6 sp2 hybridized C atoms bonded to one another, and each C is bonded to a single H atom by sigma bonds. The p orbitals of the 6 sp2 overlap, forming a continuous pi bond that lies above and below the plane of the 6 C atoms. Delocalization of the pi electrons over the 6 C nuclei can be represented by the resonance structures of benzene. Benzene's delocalization of pi electrons makes it more stable, so it readily undergoes electrophilic substitution rxns but not addition reactions like other unsaturated aliphatic and cyclic compounds do. Only one isomer exists for 1,2-disubstituted benzene compounds.

Electrophilic addition of interhalogens to alkenes

Compounds in which two or more halogens are combined in a molecule are called interhalogens. Differences in electronegativity between the halogens will result in an electro feel like region of the molecule, and this determines which halogen will attack the pie bond. Addition reactions of halogens, interhalogens, and hydrogen halides to symmetrical Alkenes all undergo the same mechanism as with and unsymmetrical Alkene. Difference is that Markovnikov's rule does not apply

Atructural isomers

Compounds with same chemical formula but different structural formula. Have unique chemical and physical properties.

What kinds of reactions can alcohols undergo?

Diverse group of compounds with a wide range of applications that play a significant part in synthetic reactions. Alcohols are polar with hydrogen bonding and a higher mpt/bpt. They will dissolve in water, but a huge nonpolar structure can hinder this. Easy for primary alcohols to undergo reactions, and gets harder for secondary, and hard for tertiary. Can undergo complete combustion, releasing CO2 and H2O. Can be oxidized using acidified potassium dichromate (VI) (milder) or potassium permanganate (VII). Products of oxidation depend on the type of alcohols involved. All alcohols can undergo condensation reactions with organic acids to form ester and water in the presence of sulfuric acid and heat (often through steam but not necessarily).

Planck's equation

E=hv=hc/LAMBDA. h is Planck's constant. Energy is directly proportional to the frequency and inversely proportional to the wavelength.

Global efforts to reduce greenhouse gas emissions

EPA estimates that 80 million tons of methane annually can be attributed to ruminant livestock. Landfill in developed countries contains an increasing amount of organic "green" waste and kitchen waste; in anaerobic conditions common in landfill sites, microbes produce methane in vast quantities in a form of anaerobic respiration called methanogenesis. Developing technologies to use the methane ti generate electricity for domestic power grids; some govts and local councils collect green waste to compost instead of sending it to landfill

For secondary halogenoalkanes, which type of nucleophilic substitution?

Either type depending on conditions.

EMS

Electromagnetic spectrum. Radio waves, microwaves, infrared, visible light (ROYGBV), ultraviolet radiation, x-rays, gamma rays. From radio waves to gamma rays: wavelength (LAMBDA) decreases, energy increases, and frequency increases. Frequency and energy are directly proportional, and wavelength is inversely proportional to them both.

Initiation

First stage of free-radical substitution. The homolytic fission of the molecule in the presence of UV light (or really high temp), producing two radicals with short lifespan. This one molecule begins the whole thing, and propagation automatically happens next until all have predominantly changed. THIS DOESN'T JUST HAPPEN—you need either a really high temp or to expose it to UV radiation. Not normal conditions. Also, methane is the main organic compound that they're going to use for this. No other way to get a halogen on methane.

Proton nuclear magnetic resonance (1H NMR) spectroscopy

Gives information on the different chemical environments of hydrogen atoms in a molecule and is possibly the most important structural technique available to organic chemist. Spin states allow hydrogen nuclei to act as tiny magnets. When nuclei are placed in a magnetic field, the spin states may align with or against the magnetic field, resulting in 2 nuclear energy levels. Parallel alignment of nuclear spin with external magnetic field is of lower energy than anti-parallel alignment. This difference in energy between two levels corresponds to the radiowave region of the electromagnetic spectrum. As applied magnetic field is increased, the change in energy will increase. The energy difference depends on the different chemical environments of the hydrogen atoms. In the spectrum, position of the NMR signal relative to a standard (tetramethylsilane, TMS) is the chemical shift expressed in parts per million of the proton. For TMS, the chemical shift=0. Hydrogen nuclei in different chemical environments have different chemical shifts. The number of signals on the spectrum shows the number of different chemical environments in which the hydrogen atoms are found. It contains an integration trace that shows the relative number of hydrogen atoms present. Important application of this type of spectroscopy is associated with the fact that protons in water molecules within human cells can be detected by magnetic resonance imaging (MRI), which gives a 3-D view of organs in the human body. Works with magnets and radio frequencies. Interpreted and compared to known values. Tells about H in the compound, which responds differently to energy when it's attached to different groups.

Protic solvents

Have H...organic acids, ammonia with a little water.

cis-trans isomers

Have at least one double bond between carbons and matching attachments on the doubly bonded C's. It's about where things are located in relation to the double bond. You can also call them E-Z isomers, but cis-trans is more predominantly used. For E-Z, you need to identify the priority mass and say if the two priority masses are on same or opposite sides of the C=C.

Stereoisomers

Have identical molecular formulas and bond multiplicity, but show different spatial arrangement of the atoms. Two major classes, confirmational and configurational. Has to do with the 3-D structuring of the compound.

Trans-isomers

Have substituents on opposite sides of the carbon carbon double bond.

Cis-isomers

Have substituents on the same side of the carbon carbon double bond.

Isomers

Huge role in organic structures—carbs, lipids, and proteins can produce isomers. Two similar structures, but not everything is in same spot. Same atoms and same number of each. Difference is structure (structural diagram) and name.

Explanation of the use of TMS as reference standard in 1H NMR spectroscopy

In this type of spectroscopy it is not possible to associate the position of absorption peaks with a wavelength or frequency, as it depends on the strength of the external magnetic field. Therefore, frequencies can be variable, as no two magnets will be identical, so universal reference standard has been agreed as TMS. TMS was used because: 1. Has 12 protons in same chemical environment, so there will be one single peak, which will be strong. Chemical shift of this signal is assigned 0 ppm, and all other chemical shifts are measured relative to it. 2. TMS is inert, so won't interfere with sample being analyzed. 3. Will absorb upfield, far from most other protons in organic compounds, which typically absorb downfield. 4. Volatile (bpt of 26-27°C), so can be easily removed from sample after measurement.

Infrared spectroscopy

Infrared radiation doesn't have enough energy to cause electronic transitions, but it can cause molecular vibrations, which result from the vibration of certain groups of molecules about their bond. Therefore, infrared spectroscopy is used to identify various functional groups in a molecule. The vibrational transitions correspond to definite energy levels. The basis is the spring model, in which every covalent bond is considered as a spring which can be stretched (symmetrically and asymmetrically), bent, or twisted, giving rise to a distortion. v = (1/2pi) (sqrt. k/m), where v is fundamental frequency of the vibration. Lighter atoms vibrate at greater frequencies, and more multiple bonds means lower frequencies, because there's more energy required to stretch it. Diatomic molecules can only stretch. Different molecules absorb at different frequencies because the energy required will depend on bond enthalpy. Infrared absorptions are typically cited as one over lambda, the wave number with units of centimeters to the -1st. For a polyatomic species, may be several different modes of vibration. For example, water has a symmetrical stretch, and asymmetrical stretch, and a symmetrical bend. For a covalent bond to absorb infrared radiation, there must be a change in the molecular dipole moment associated with the vibration mode. Absorbance, A, of a sample can be related to transmittance, T: A=-log(base10)T. The infrared spectrum is a plot of percent transmittance versus wave number, where percent transmittance ranges from 0% to 100%. Functional groups can be identified from characteristic ranges for infrared absorption of various bonds in different molecule classes and of different functional groups. The fingerprint region of an IR spectrum is 300 to 1400 cm to the -1st, where more complex vibrations can be identified. Infrared spectroscopy is a supporting analytical technique because it provides little structural info, but powerful in making some key decisions at the beginning of structural elucidation of a compound. Give energy, record the response. Shows bond position, what atoms are connected to each other, what atoms are involved. Each dip is an inverted peak, and they're used to determine which atoms there are and what they're doing. Compare the numbers of the inverted peaks with a chart to get this info. The sample in the spec is exposed to light, it bounces around, and then it's brought to a sensor for detection. Charts give absorption frequency regions for specific bonds/functional groups. Gives possibilities—arduous process. Once you've identified them, you can try to figure out their position in structure.

List the stages of free-radical substitution

Initiation, propagation, termination

electrophilic substitution reactions

Instead of addition reactions benzene will undergo electrophilic substitution reactions. An electrophile is an electron poor species capable of excepting an electron pair. They are Lewis acids. While electron poor electrophiles are attracted to the pi electrons in the aromatic benzene ring, the stability of the ring leads to substitution rather than addition

Electrophilic addition of halogens to alkenes

Often used as test for unsaturation in org mlcls. Halogen is a nonpolar molecule with a net dipole of 0. It is polarized as it approaches the electron rich C=C of the alkene. Electrons within the halogen molecule are repelled, resulting in a temporary dipole.

Addition polymerization usually takes place where?

On a metal—metal catalyst (Heterogeneous). Atoms/molecules go there and attach before atoms are transferred to alkane.

Nucleophilic substitution reactions

Once an unreactive alkane has undergone a substitution reaction to form a halogenoalkane, the resulting molecule can take part in other types of reactions. It contains a polar carbon to halogen bond, and the electron deficient carbon is now open to attack by electron Rich species called nucleophiles, which contain a lone pair of electrons and sometimes carry a full negative charge. Nucleophiles are Lewis basis. This type of reaction is called nucleophilic substitution reaction. There a different possible reaction mechanisms that depend on the class of halogenoalkane present.

Aldehydes

One aldehyde attached. Functional group: —COH. (The C is double bonded to the O.) General formula: R—COH. Naming rules: name longest hydrocarbon chain (including the C in the carbonyl group), drop "e" and add suffix -al.

Ketones

One carbonyl attached. Functional group: —CO. (C is double bonded to O. General formula: R—CO—R'. Naming rules: name longest hydrocarbon chain (including C in carbonyl group), drop "e" and add suffix -one. Numner to lowest carbon.

Esters

One ester attached. Functional group: —COO. (One O is double bonded to the C, and the other is single bonded with an open bond as well.) General formula: R—COO—R'. Naming rules: Prefix is from alcohol—change name of carbons to alkyl group name. Ending is from organic acid—drop "oic acid" and change to "oate." Very specific smell.

Ethers

One ether attached. Functional group: —O—. General formula: R—O—R'. Naming rules: prefix = # of carbons for smaller carbon group, oxy (for oxygen), and suffix = alkane name for larger carbon group.

Unsaturated compounds

One or more double or triple bonds (multiple bonds). Alkenes, alkynes, aromatic hydricarbons.

Halogenoalkanes

One or more halogen attached. Functional group: —X. General formula: R—X. Naming rules: name longest hydrocarbon chain and any attached alkyl group prefix for attached halogen (bromo, chloro, fluoro, iodo). Number to lowest carbon.

Alcohols

One or more hydroxyl group attached. Functional group: —OH. General formula: R—OH. Naming rules: name longest hydrocarbon chain. Drop "e" and add suffix -ol. (Keep "e" for 2, -diol, 3, -triol, 4, -tetraol.) Number to lowest carbon.

Background to designing a synthetic route

Organic synthesis takes a starting material and converts it via a series of reactions into the desired product. Each step produces an intermediate in quantities less than the theoretical yield, so efficient synthetic pathway involves the smallest number of steps. For equilibrium reactions, choose conditions to favor the products, thereby increasing final yield. Reactions that convert one functional group to another, like the oxidation of a primary alcohol to a carboxylic acid or the nucleophilic substitution of halogenoalkane, don't change the length of the carbon chain. Synthetic tools include controlled chain-lengthening and change-shortening reactions, while polymerization involves the formation of long molecules made up of repeating monomer units.

Hydrogenation

The addition of hydrogen to unsaturated hydrocarbons in the presence of a catalyst.

Torsional strain/energy

The energy difference between the staggered and eclipsed conformations. Result of repulsion between bonding electrons. In an eclipsed conformation, pairs of bonding electrons in the carbon hydrogen bonds will repel one another.

Organic chemistry

The field of chemistry that studies carbon-based compounds. Wide and varied field. Carbon compounds—so covalent only. CO, CO2, CO3 2-, and CN1- are not organic. Just because something is organic doesn't mean it's not involved with organic compounds, as the carbon oxides are certainly involved. Organic compounds may or may not be part of living things. Biochemistry is focused just on organic compounds in living things- subset of organic compounds. Empirical formulas play a huge role, as compounds with similar empirical formulas are classified together have similar properties.

Bonding for aromatic hydrocarbons

They are unsaturated and very difficult to break, because the alternating single and double bonds make each bond a 1 1/2 bond, so very stable. Harder to break than a compound with one double bond or one triple bond on each end.

Temination

Third stage of free-radical substitution. Reduces the concentration of radicals in the reaction mixture. Termination reactions become more prevalent when the concentration of the hydrocarbon begins to decrease. They "mop up" the radicals, decreasing the rate of reaction and eventually stopping it completely. Radicals join to form stable compounds.

Optical isomers and plane-polarized light

Under same conditions, two optical isomers with the same general formula rotate the plane of polarized light in the same angle but in opposite directions. The one that rotates it in a clockwise direction is the positive enantiomer. The one that rotates it in an anti-clockwise direction is the negative enantiomer. A 50-50 mix of the two enantiomers is called a racemic mixture or a racemate. This doesn't rotate plane-polarized light. A polarimeter can be used to determine optical purity of the products of synthetic reactions. Common technique in industry producing optically active products. The products affect on plane-polarized light can be compared with literature values to determine the purity of the desired enantiomer.

Lewis (electron-dot) structures

Useful to visualize the valence electrons present in similar mlclr compounds and polyatomic ions

Walden inversion

When a chemical species with an sp3 C center and tetrahedral geometry undergoes a backside attack by a nucleophile in an SN2 reaction, a configurational change occurs. This inversion provides room for the entering nucleophile, while the product has the same relative configuration as the reactant.

Heterolytic fission

When both electrons move together to form a new bond. Creates a cation and an anion, as the electrons involved in the bond are unevenly split between the two atoms.

Molecular formula

describes the actual number of atoms of each element present in a molecule. Doesn't give info about structure.