OpenLLM-France/wikimedia huggingface dataset:
# Ethers

Ethers can be derived from alcohols. The functional group of ethers is R-O-R (instead of R-O-H in an alcohol). Ethers can be viewed as a water molecule in which both H atoms are replaced with alkyl groups. Ethers may exist in straight chain carbons (acyclic) or as part of a carbon ring (cyclic).

# Preparation of ethers
### Synthesis of acyclic ethers

Most acyclic ethers can be prepared using Williamson's synthesis. This involves reacting an alkoxide with a haloalkane. As stated previously, alkoxides are created by reacting an alcohol with metallic sodium or potassium, or a metal hydride, such as sodium hydride (NaH). To minimize steric hindrance and achieve a good yield, the haloalkane must be a primary haloalkane. This is because the mechanism is S$_N$2, where the oxygen atom does a backside attack on the carbon atom with the halogen atom, causing the halogen atom to leave with its electrons.

### Synthesis of cyclic ethers

You can also use the Williamson synthesis to produce cyclic ethers. You need a molecule that has a hydroxyl group on one carbon and a halogen atom attached to another carbon. This molecule will then undergo an S$_N$2 reaction with itself, creating a cyclic ether and a halogen anion.

# Properties of ethers
## Acyclic ethers
### Naming acyclic ethers

Name the two sides of the ether as substituents, then add the word "ether" at the end. For example, CH$_3$-O-CH$_3$ is dimethyl ether. CH$_3$-O-C(CH$_3$)$_3$ can be called methyl tert-butyl ether (MTBE) or tert-butyl methyl ether (TBME).

### Cleavage of acyclic ethers

Acyclic ethers can be cleaved by a strong acid, typically HI or HBr, but not HCl. The acid breaks the ether apart into an alcohol and an alkyl halide (a haloalkane.) Cleavage of ethers by an acid was first seen by Alexander Butlerov in 1861, when he discovered that hydroiodic acid causes 2-ethoxypropanoic acid to break apart into iodoethane (ethyl iodide) and lactic acid (2-hydroxypropanoic acid.) The mechanism used in acidic cleavage of ethers depends on whether they have primary, secondary, or tertiary groups attached to oxygen. If one of the carbons attached to the central oxygen atom is tertiary, benzylic (contains benzene ring), or allylic (contains carbon-carbon double bond), then the cleavage will occur via an S$_N$1 or an E1 mechanism. The E1 mechanism leads to an alcohol and an alkene instead of an alkyl halide. These reactions often take place around 0 degrees C. On the other hand, if both groups attached to the central oxygen atom are primary or secondary, the reaction takes place via an S$_N$2 mechanism. These reactions are often conducted at 100 degrees C.

## Cyclic ethers

Two common cyclic ethers are epoxide, which has two carbons each bonded to the oxygen atom; and tetrahydrofuran, known by its abbreviation THF, which has four carbons and an oxygen atom.
# Organic Chemistry/Dienes

Organic chemistry > Dienes
<< Alkynes | Kinds of dienes >>
In alkene chemistry, we demonstrated that allylic carbon could maintain a cation charge because the double bond could de-localize to support the charge. What of having two double bonds separated by a single bond? What of having a compound that alternates between double bond and single bond? In addition to other concepts, this chapter will explore what a having a conjugated system means in terms of stability and reaction.
Dienes are simply hydrocarbons which contain two double bonds. Dienes are intermediate between alkenes and polyenes.
Dienes can divided into three classes:
* Unconjugated dienes have the double bonds separated by two or more single bonds. These are also known as isolated dienes.
* Conjugated dienes have conjugated double bonds separated by one single bond
* Cumulated dienes (cumulenes) have the double bonds sharing a common atom as in a group of compounds called allenes.
* Kinds of dienes
* Conjugation
* Diene properties and reactions
<< Alkynes | Dienes | Aromatics >>
# Organic Chemistry/Dienes/Conjugation

Organic chemistry > Dienes > Conjugation
<< Kinds of Dienes | Diene Properties and Reactions >>

### Conjugation of Double Bonds

A diene is said to be conjugated when its double bonds are not directly next to each other, but rather separated by a single bond in between them (CH$_2$=CH-CH=CH$_2$).
Conjugated dienes are particularly stable due to the delocalization of the pi electrons along sp$^2$ hybridized orbitals, and they also tend to undergo reactions atypical of double bond chemistry. For instance, chlorine can add to 1,3-butadiene (CH$_2$=CH-CH=CH$_2$) to yield a mixture of 3,4-dichloro-1-butene (ClCH$_2$-CHCl-CH=CH$_2$) and 1,4-dichloro-2-butene (ClCH$_2$-CH=CH-CH$_2$Cl). These are known as 1,2 addition and 1,4 addition, respectively. 1,2-addition is favored in mild reaction (irreversible) conditions (the kinetically preferred product) and 1,4-addition is favored in harsher reaction (reversible) conditions (which results in the thermodynamically preferred product).
Another interesting conjugated diene reaction is the Diels-Alder reaction, in which a conjugated diene reacts with an alkene (called a "dienophile" in this case) in order to yield a cyclic product. In Diels-Alder type reactions, the substituent on the dienophile will go into either an exo or endo position in the final product. ("Endo" in this case meaning trans to the substituents on the ends of the diene, and "exo" meaning the same thing, only cis.)
<< Kinds of Dienes | Diene Properties and Reactions >>
# Organic Chemistry/Dienes/Diene properties and reactions

Organic chemistry > Dienes >Diene Properties and Reactions
<< Conjugation | Next Chapter: Aromatics

### Common Reactions of Conjugated Dienes

Conjugated dienes have enhanced stability as compared to molecules without conjugated double bonds due to resonance. In general, this makes them slightly less reactive than other types of alkenes in general and dienes specifically. However, many reactions proceed through high-energy cation or radical intermediates; in these cases the resonance stabilization of the intermediate allyl species makes conjugated dienes more reactive than non-conjugated dienes or simple alkenes.

## Hydrobromination:

Adds a Bromine and a Hydrogen to a conjugated Diene.
Example:
Butadiene + HBr--> 3-bromobutene (Low Temperature) + 1-bromobut-2-ene (High Temperature) + 1-bromobutene (Not Observed)
Thermodynamic and Kinetic Control of Reaction:
* At low temperature the reaction is under KINETIC CONTROL: the 3-bromobutene is formed faster because it has a lower transition state free energy, as the intermediate cation is more stable at the secondary carbon.
* At high temperature the reaction is under THERMODYNAMIC CONTROL: the 3-bromobutene still forms more quickly, but the reaction has enough energy to reverse, and the more stable product (1-bromobut-2-ene) is formed.

## Diels-Alder Reaction

One of the most important of all diene reactions is the Diels-Alder Reaction, in which a conjugated diene reacts with an dienophile to form a cyclohexene.
Requirements: The diene must be able to access the s-cis conformation for the reaction to take place.
DIENEOPHILES - A species which likes to attack Dienes
- A Dienophile must contain a double or triple bond. Typically, an electron withdrawing group is conjugated to the dienophile to make it electron-poor (nitriles, ketones, and esters are common electron withdrawing groups). Because the reaction is highly stereospecific, the configuration of the dieneophile will determine the relative stereochemistry of the cyclohexene product.
The Diels-Alder reaction occurs most effectively with an electron-poor dieneophile and an electron-rich diene ('normal demand'). 'Inverse demand' Diels-Alder reactions can also be carried out, in which the dienophile is electron-rich and the diene electron-poor.
<< Conjugation | Next Chapter: Aromatics
# Organic Chemistry/Foundational concepts of organic chemistry

The purpose of this section is to review topics from freshman chemistry and build the foundation for further studies in organic chemistry.
* History of organic chemistry
* Atomic structure
* Electronegativity
* Bonding
* Electron dot structures
* Visualization
* Resonance
* Acids and bases
* Nomenclature
| Alkanes >>
# Organic Horticulture in the Mid-Atlantic/Pokeweed

| Phytolacca americana (pokeweed) is a shrub-like native herbaceous perennial with green or reddish stems, large leaves, and a long, fleshy taproot. The plant's seeds are berries that are spread by birds, and frequently are found around the driplines of trees, shrubs, and along fencerows. Pokeweed can be difficult to pull due to the very heavy and deep taproots, and a full-sized mattock may be required for large specimens. Seed supplies can be reduced by at least cutting down plants in adjacent uncultivated areas before the berries ripen. Seeds may germinate under mulch, and paper barriers are ineffective as the plant can push through. Pokeweed shoots can be composted in cold piles if berries are not present (roots should not be added to cold piles). | Flowers Root |
# Organic Horticulture in the Mid-Atlantic/Rudbeckia triloba

Rudbeckia triloba, the Brown-eyed Susan, is a native wildflower in the Mid-Atlantic, but can also become quite weedy in the garden or field. It is a short-lived perennial, producing flowers in summer and fall. Germination occurs any time during the growing season.
Plants are usually best controlled by pulling. Prevent reseeding by removing spent flowers.
The plant is sometimes cultivated, so consult the garden planner before eradicating. Spent flowers are sometimes left on the plant to attract birds such as the goldfinch or house finch.
Cold-pile composting is safe if flowers or seeds are not present.
# Organic Horticulture in the Mid-Atlantic/Tree rings

In the horticultural sense, a tree ring is an area around the trunk of the tree that is maintained as a barrier between the surrounding lawn and the tree's base to avoid unintentional damage from mowing equipment. This area is generally kept mulched or planted with a ground cover or other ornamental plants. "Tree ring" is also a colloquial term for the annual growth rings found in a tree's wood.
Tree rings provide an important purpose in protecting the tree, since being bumped by mowers or hit by rotary weed trimmers can cause severe damage to the base of the tree by either crushing or removing the cambium layer (thus causing a dead area), or by simply exposing the cambium which makes the tree susceptible to infection or insect damage since the protective bark is removed. Eventually this can cause the parts of the tree above the damaged area to die, or in extreme cases the whole tree can die due to disease or unintentional girdling.
Tree rings should at a minimum be at least 1 foot (30 cm) beyond the flare of the tree's base, though wider is better. If there are surface roots beyond the tree ring that are being hit by mowing equipment, the ring should be expanded to include those roots, since scarfing the roots also created open wounds and thus make the tree susceptible to infection.
While tree rings are often maintained by simply maintaining a layer of mulch, the use of ground covers is a much better option in most cases, since the presence of a ground cover will discourage people from walking on the soil within the ring, and so helping to avoid soil compaction. Dense ground covers such as Pachysandra terminalis, Epimedium, and so on are the best choices, since they require less weeding and so less foot traffic within the ring.
In cases where surface roots continue to appear outside of an existing tree ring, vertical mulching can be used to provide better air, water, and nutrient circulation within the deeper soil, which will encourage the tree to grow deep roots rather than surface roots.
# Organic Horticulture in the Mid-Atlantic/Pinkweeds

| Pinkweeds, otherwise known as smartweeds or lady's thumbs are any of a number of plants in the genus Persicaria (formerly Polygonum), including both native and invasive species. The weedy species are all annual plants with simple, smooth-margined leaves, and often have a dark marking (a "lady's thumbprint") in the center of each leaf. The leaves and branches are alternate, with each node somewhat swollen and covered by a thin sheath (the old genus name "Polygonum" roughly means "many-knees"). Pinkweeds have a fibrous root system and may root at the nodes where the stems touch the ground. Grubbing out is generally easy, and cultivators may be used on young plants. With the exception of the young seedlings, plants should be composted only in hot systems, since the plants can continue to grow and/or set seed in cold piles. Some species of Persicaria are grown as garden plants as well, though these species tend to look quite different from the weedy types. | Along a garden edge P. maculosa, showing rootCloseup of stem node |
# Organic Horticulture in the Mid-Atlantic/Vinca minor

Wikimedia Resources for Vinca minor on Wikimedia projects :
| Wikipedia | Wikipedia |
| Wikiversity | Wikiversity Bloom Clock |
| Commons | Wikimedia Commons (category) |
| Wikibooks | Horticulture (Cookbook) |
Vica minor, usually called Periwinkle or simply Vinca, is a spreading evergreen vine commonly grown as a ground cover. It bears a large set of flowers in mid-spring, and then flowers sporadically the remainder of the year. Various cultivars are available in the trade, with flower colors ranging from white through pink, reddish-purple, lavender, and dark purple. Cultivars with variegated leaves are also available.

## Culture

V. minor grows well in both full sun and fairly deep shade, though a bit thinner in shade. It spreads as a vine, rooting both at the nodes and between the nodes. It does best in a rich soil, but tolerates poor soils. It is drought tolerant once established, but does not do well in wet soils.
As a ground cover, V. minor spreads rapidly, but does not grow dense enough to suppress weeds. It can also be very difficult to keep weeded if spreading perennial weeds gain a foothold (such as Duchesnea indica, Artemisia vulgaris, Cirsium arvense, Vetch, etc.), since the wire-like vines of the plant form a dense tangle that makes it difficult to remove the weeds without also doing damage to the plant itself.
# Organic Horticulture in the Mid-Atlantic/Wild Onions

The weedy species of wild onions in the Mid-Atlantic are generally one of two species: the invasive Allium arvense or the native Allium canadensis. For horticultural purposes, they are both treated in the same way as weeds, though A. arvense tends to form larger clumps and is more likely to become a weed of lawns.
Both plants need to be grubbed using a weeding tool that can get the roots out, since the roots tend to be deep and the stems easily break away allowing the plant to regrow. Both species will grow back from either the main bulb or the bulblets, so the area should be inspected for weed regrowth a week or two after the initial grubbing.
# Organic Horticulture in the Mid-Atlantic/Print version 6.16.08-001

This is a print version for "Organic Horticulture in the Mid-Atlantic", prepared June 16, 2008 by --SB_Johnny |
| Lamb's Quarters (Chenopodium album) is an annual invasive weed most commonly found in dry, nitrogen-rich soils. The alternate, somewhat "kite-shaped" leaves have a dusty appearance. Stems are stout, longitudinally ridged, and also whitish. Roots consist of large taproots with numerous laterals. Pulling and grubbing is relatively easy, since the root and shoot are strongly connected. This plant is safe to compost in cold piles before the flowers appear in summer. Flowers are greenish terminal spikes. While rarely seen in Mid-atlantic gardens, the culinary grain Quinoa (C. quinoa) is almost indistinguishable from the weed species, so maintenance crews should always be advised if that species is being grown in the garden. Epazote, or Wormseed (Dysphania ambrosioides) is somewhat similar when in flower, but the foliage is markedly different from Lamb's Quarters. | young plant flowerbudsflowers |
| The genus Oxalis (Woodbines) contains both native and invasive weedy species that are common throughout the region. Two species are erect annuals, while the third is a creeping perennial. All species have trifoliate leaves with heart-shaped leaflets. On the annual types the leaves are a pale green, while on the perennial creeping species the leaves are purplish. Flowers are small, yellow, and trumpet-shaped with 5 lobes. Horn-like seed pods soon follow, opening explosively when ripe. When pulling oxalis, plants should always be put directly into a container (not piled) to avoid broadcasting the seeds. With the exception of very small seedlings, they should never be composted in a cold pile. The creeping species (O. corniculatus) will regrow from small root fragments, so care must be taken to get the entire root. It can be distinguished from the other species by the purplish cast to the foliage and a lower growing habit rooting at the nodes. | O. stricta Creeping woodsorrel, O. corniculatusflower |
# Organic Chemistry/Alkanes/Propane thru decane

<< Ethane | Stereoisomers >>
Many more linear alkanes can be formed by adding one additional carbon to the end of a chain of carbons. Ethane is the shortest chain with two carbons but DNA is known to have carbon chains containing millions of linked carbons.
Alkanes are named based on the number of carbons in their longest chain:

### Naming carbon chains up to ten

* methane (1 carbon)CH4
* ethane (2 carbons)C2H6
* propane (3 carbons)C3H8
* butane (4 carbons)C4H10
* pentane (5 carbons)C5H12
* hexane (6 carbons)C6H14
* heptane (7 carbons)C7H16
* octane (8 carbons)C8H18
* nonane (9 carbons)C9H20
* decane (10 carbons)C10H22
The general equation for Alkanes is CnH2n+2.(Substute the n with no.of carbons, eg:-Propane 3 C 'C3H2*3+2=C3H8')
The suffixis on the first four are from an obscure system but you should be familiar with the rest.
Propane and butane are gases at standard temperature and pressure and are used commonly in lighters. Pentane on down the list are liquids at STP. Octane is the same as the octane in your gas tank.
You may also want to name hydrocarbon chains of more than ten carbons. Here is a list for your reference:

### Naming longer carbon chains

* triacontane (30 carbons)
* tetracontane (40 carbons)
* pentacontane (50 carbons)
* hexacontane(60 carbons)
etc...
As the carbon chains get longer, molecules get relatively heavier and tend to move from being gases at Standard Temperature and Pressure to liquids to waxy solids.
Foundational concepts >> | << Alkanes | << Ethane | Propane thru decane | Drawing alkanes >> | Introduction to reactions >>
# Organic Chemistry
## Contents
### Front Matter

* Welcome
* Authors
* Licensing
* Foreword

### Chapters

* Foundations of Organic Chemistry
* Alkanes
* Stereochemistry
* Chirality
* Cycloalkanes
* Alkenes
* Alkynes
* Overview of Functional Groups
* Haloalkanes
* Alcohols
* Ethers
* Amines
* Dienes
* Aromatics
* Aromatic reactions
* Ketones and aldehydes
* Carboxylic acids
* Carboxylic acid derivatives
* Analytical techniques
* Questions and Discussions

### Supplemental material

* Appendix A: Introduction to reactions
* Appendix B: Index of reactions
* Appendix C: Introduction to functional groups
* Glossary
* Periodic table
* Short periodic table
* Other online resources

## Administrative

* To-Do List
* Help organize the book structure.
* Page element templates

## See also

* Morrison and Boyd ISBN 0-13-643669-2
* Solomons and Fryhle ISBN 978-0471417996
* Wade ISBN 978-0131699571
* Carey ISBN 978-0072979527
* McMurry] ISBN 978-0534389994
* Daley & Daley Free
# Ethane

<< Methane | Propane thru decane >>
Ethane (/ˈɛθeɪn/ or /ˈiːθeɪn/) is a chemical compound, or hydrocarbon with a chemical formula of C2H6. At standard temperature and pressure, ethane is a colorless, odorless gas. Ethane is isolated on an industrial scale from natural gas, and as a byproduct of petroleum refining. Its chief use is as petrochemical feedstock for ethylene production. It could be described as two methane molecules attached to each other, less two hydrogens.

### Number of hydrogens to carbons

This equation describes the relationship between the number of hydrogen and carbon atoms in alkanes:
    H = 2C + 2
where "C" and "H" are used to represent the number of carbon and hydrogen atoms present in one molecule. If C = 2, then H = 6.
Many textbooks put this in the following format:
    C$_N$H$_{2N+2}$
where "C$_N$" and "H$_{2N+2}$" represent the number of carbon and hydrogen atoms present in one molecule. If C$_N$ = 3, then H$_{2N+2}$ = 2(3) + 2 = 8. (For this formula look to the "N" for the number, the "C" and the "H" letters themselves do not change.)
<< Organic chemistry | << Alkanes | << Methane | Ethane | Propane thru decane >> | Introduction to reactions >>
# Methane

<< Foundational concepts | Ethane >>
Methane, CH$_4$ is the simplest organic molecule. It is a gas at standard temperature and pressure and is a carbon atom with four hydrogen atoms bonded to it in a tetrahedral shape.
* Methane
This is a flattened, two-dimensional representation of methane that you will see commonly. The true three-dimensional form of methane does not have any 90 degree angles between bonded hydrogens. The bonds point to the four corners of a tetrahedron, forming cos$^{−1}$(−1/3) ≈ 109.5 degree bond angles.
<< Foundational concepts | << Alkanes | Methane | Ethane >> | Introduction to reactions >>
# Organic Chemistry/Alkanes/Cycloalkanes/Conformations

Different arrangements of atoms that can be converted in to one another by rotation about single bonds are called conformations. there are infinite arrangement which arise due free rotation around carbon - carbon sigma bond , different conformations corresponding to energy minima are called conformational isomers . the conformational isomerism arises due to free rotation along a bond
# LMIs in Control/LMIs for Controller Synthesis

      * Quadratically Stabilizing Controllers with Parametric Norm-Bounded Uncertainty
      * H-infinity Optimal Quadratically Stabilizing Controllers with Parametric Norm-Bounded Uncertainty
      * Stabilizing State-Feedback Controllers with Structured Norm-Bounded Uncertainty
      * Optimal State-Feedback Controllers with Structured Norm-Bounded Uncertainty
      * LMI for Mixed H2/Hinf Output Feedback Controller
      * LMI for Decentralized Feedback Control