about the hydroxyl functional group the Hydroxyl radical Hydroxyl radical multiple issues expert Chemistry date December 2011 cleanup December 2011 refimprove December 2011 File Hydroxyl3D.png thumb right 200px Representation of an organic compound organic hydroxyl group, where R represents a hydrocarbon or other organic moiety, the red and grey spheres represent oxygen and hydrogen atoms, respectively, and the rod like connections between these, covalent chemical bond s. A hydroxyl is a chemistry chemical functional group containing an oxygen atom connected by a covalent bond to a hydrogen atom , a pairing that can be simply understood as a substructure of the water molecule . When it appears, it imparts to chemical structures some of the reactive and interactive properties of the OH of water ionizability , hydrogen bonding , etc. . The neutral form of the hydroxyl group is a hydroxyl radical . The anion form, OH sup sup is called the hydroxide anion it bears a single negative charge largely residing on the more electronegative oxygen. Hydroxyl group The hydroxyl group is prevalent in organic chemistry , where it is the defining functional group in alcohol s ethanol , methanol , etc ... water solubility and internal structural stability to macromolecules , etc. Hydroxyl radical main Hydroxyl radical Hydroxyl radicals are highly reactive and undergo Radical chemistry chemistry that makes ... spacecraft and the Deep Impact probe have each detected the presence of water by evidence of hydroxyl ... an ultraviolet emission spectrum consistent with hydroxyl presence. ref name nasa cite web url ... of hydroxyl in the atmosphere. See also Wiktionary Commons category Hydroxyl group Hydroxide ... Category Alcohols ar bg bs Hidroksil grupa ca Grup hidroxil cs Hydroxyl da ... la Hydroxydatum mk nl Hydroxylgroep ja no Hydroksyl nds Hydroxyl Grupp pl Grupa hydroksylowa pt Hidroxila ro Grup hidroxil ru sk Hydroxyl sr Hidroksil ... more details
In chemistry , the hydroxyl value is a measure of the content of free hydroxyl groups in a compound, typically a fat, oil, or natural or synthetic ester . This value is a useful measure of the degree of Esterification Esterification of carboxylic acids esterification in ester synthesis. The method involves acetylation of the free hydroxyl groups of the compound with acetic anhydride in pyridine solvent http www.astm.org Standards D1957.htm . After completion of the reaction, water is added, the remaining acetic anhydride is converted to acetic acid , and measured by titration with potassium hydroxide. Other functional groups, such as primary or secondary Amine amines , will be reported as hydroxyl. It is expressed as the mass of potassium hydroxide KOH in milligrams equivalent to the hydroxyl content of one gram of the chemical substance , corrected for carboxyl hydroxyl groups by titration of an unacetylated sample of the same material. math HV V B W acet V av W av V acet W acet N56.1 math Where V sub B sub is the amount of titration titrant ml consumed by the blank, at the equivalent point, W sub acet sub is the weight of sample in grams used for acetylation, V sub av sub is the amount of titrant used for determining the acid value, W sub av sub is the weight of sample used for determining the acid value, V sub acet sub is the amount of titrant used for the acetylated sample, N is the normality of the titrant, and 56.1 is the molecular weight of Potassium hydroxide KOH . The standard method for determining the hydroxyl value is ASTM D 1957 See also Saponification value Iodine value Acid value DEFAULTSORT Hydroxyl value Category Analytical chemistry Category Lipids ... more details
121 ImageName Stick model of the hydroxyl radical with molecular orbitals IUPACName Hydroxyl radical SystematicName Oxidanyl ref name Hydroxyl CHEBI 29191 Cite web title Hydroxyl CHEBI 29191 url http ... name Hydroxyl CHEBI 29191 additive OtherNames Hydroxy br Hydroxyl br sup 1 sup Oxidanyl Section1 Chembox ... 2D skeletal.png thumb Skeletal formula e of 1 hydroxy 2 1H pyridinethione and its tautomer The hydroxyl radical , sup sup OH , is the neutral form of the hydroxide ion OH sup sup . Hydroxyl radicals ... radical chemistry . Most notably hydroxyl radicals are produced from the decomposition of organic ... cracking SCC in coolant systems subjected to radioactive environments. Hydroxyl radicals are also ... mediated oxidations of organic compounds. In organic synthesis hydroxyl radicals are most commonly generated by photolysis of 1 Hydroxy 2 1H pyridinethione . The hydroxyl radical is often referred ... assessment report ref The rate of reaction with the hydroxyl radical often determines how long many ... methane, which reacts relatively slowly with hydroxyl radical, has an average lifetime of 5 years ... Lecture notes on Atmospheric chemistry Biological significance The hydroxyl radical can damage virtually ... and amino acids e.g. conversion of Phe to m Tyrosine and o Tyrosine . PMID 7776173. The hydroxyl radical ... , the hydroxyl radical cannot be eliminated by an enzyme enzymatic reaction. Mechanisms for scavenging ... The hydroxyl sup sup OH radicals is one of the main chemical species controlling the oxidizing ......52.3428H issn 1520 0469 ref Global average hydroxyl radical concentrations have been measured indirectly ... hydroxyl journal Science pmid 21212353 volume 331 issue 6013 pages 67 69 doi 10.1126 science.1197640 ... of 18 cm absorption lines of the hydroxyl sup sup OH radical in the radio absorption spectrum ... Hydroxyl ion absorption Hydrogen darkening Notes reflist 2 References refbegin cite journal author ... volume 20 issue page 521 refend External links http www.physorg.com news130065276.html Hydroxyl found ... more details
Hydroxyl ion absorption is the Absorption optics absorption in optical fiber s of electromagnetic wave s, including the near infrared , due to the presence of trapped hydroxyl ions remaining from water as a contaminant. The hydroxyl OH sup sup ion can penetrate glass during or after product fabrication, resulting in significant attenuation of discrete optical wavelengths, e.g. , centred at 1.383 m, used for telecommunication communications via optical fibres. See also Water absorption References FS1037C Category Fiber optics Category Glass engineering and science analytical chemistry stub optics stub ... more details
enzyme Name ATP dependent polydeoxyribonucleotide 5 hydroxyl kinase EC number 2.7.1.78 CAS number 37211 65 7 IUBMB EC number 2 7 1 78 GO code 0046404 image width caption In enzymology , a polynucleotide 5 hydroxyl kinase EC number 2.7.1.78 is an enzyme that catalysis catalyzes the chemical reaction ATP 5 dephospho DNA math rightleftharpoons math ADP 5 phospho DNA Thus, the two substrate biochemistry substrates of this enzyme are adenosine triphosphate ATP and 5 dephospho DNA , whereas its two product chemistry products are adenosine diphosphate ADP and 5 phospho DNA . This enzyme belongs to the family of transferase s, specifically those transferring phosphorus containing groups phosphotransferase s with an alcohol group as acceptor. The systematic name of this enzyme class is ATP 5 dephosphopolynucleotide 5 phosphotransferase . Other names in common use include ATP 5 dephosphopolynucleotide 5 phosphatase , PNK , polynucleotide 5 hydroxyl kinase phosphorylating , 5 hydroxyl polynucleotide kinase , 5 hydroxyl polyribonucleotide kinase , 5 hydroxyl RNA kinase , DNA 5 hydroxyl kinase , DNA kinase , polynucleotide kinase , and polynucleotide 5 hydroxy kinase . Structural studies As of late 2007, 10 tertiary structure structures have been solved for this class of enzymes, with Protein Data Bank PDB accession codes PDB link 1LTQ , PDB link 1LY1 , PDB link 1RC8 , PDB link 1RPZ , PDB link 1RRC , PDB link 1UJX , PDB link 1YJ5 , PDB link 1YJM , PDB link 2BRF , and PDB link 2IA5 . References reflist 1 cite journal author Novogrodsky A, Hurwitz J date 1966 title The enzymatic phosphorylation of ribonucleic acid and deoxyribonucleic acid. I. Phosphorylation at 5 hydroxyl termini journal J. Biol. Chem. volume 241 pages 2923&ndash 32 pmid 4287929 issue 12 cite journal author Novogrodsky A, Tal M, Traub A, Hurwitz J date 1966 title The enzymatic phosphorylation of ribonucleic acid and deoxyribonucleic acid. II. Further properties of the 5 hydroxyl polynucleotide kinase journal J. Biol ... more details
A chloride hydroxyl exchanger is a purported membrane transport protein , responsible for the exchange of chloride and hydroxyl in the renal proximal tubule , functioning in renal chloride reabsorption . However, little is known about the protein responsible for this action. ref http www.nature.com ki journal v50 n6 abs ki1996513a.html Functional identity of a purified proximal tubule anion exchanger protein Mediation of chloride formate and chloride bicarbonate exchange ref . References reflist membrane transport proteins Carrier proteins Ion channels Ion pumps Neurotransmitter transporters Category Transport proteins Category Transmembrane transporters membrane protein stub ... more details
Unreferenced date December 2009 Hydroxyl tagging velocimetry HTV is a velocimetry method used in humid air flows. The method is often used in high speed combusting flows because the high velocity and temperature accentuate its advantages over similar methods. HTV uses a laser often an argon fluoride excimer laser operating at 193 nm to dissociate the water in the flow into H OH. Before entering the flow optics are used to create a grid of laser beams. The water in the flow is dissociated only where beams of sufficient energy pass through the flow, thus creating a grid in the flow where the concentrations of hydroxyl OH are higher than in the surrounding flow. Another laser beam at either 248 nm or 308 nm in the form of a sheet is also passed through the flow in the same plane as the grid. This laser beam is tuned to a wavelength that causes the hydroxyl molecules to fluoresce in the UV spectrum . The fluorescence is then captured by a charge coupled device CCD camera. Using electronic timing methods the picture of the grid can be captured at nearly the same instant that the grid is created. By delaying the pulse of the fluorescence laser and the camera shot an image of the grid that has now displaced downstream can be captured. Computer programs are then used to compare the two images and determine the displacement of the grid. By dividing the displacement by the known ... instead of hydroxyl. In the case of ozone the method is known as Ozone tagging velocimetry or OTV ... Pitz title Hydroxyl tagging velocimetry method optimization signal intensity and spectroscopy ..., J.A. Wehrmeyer, S. Hu, and R.W. Pitz title Multiline hydroxyl tagging velocimetry measurements ... title Hydroxyl tagging velocimetry HTV in experimental air flows journal Applied Physics B year ... tagging in cold and not flows using ozone and hydroxyl tagging velocimetry journal Measurement Science ... AIAAJ 1999 PVJAIMP799.pdf DEFAULTSORT Hydroxyl Tagging Velocimetry Category Measuring instruments ... more details
Chembox verifiedrevid 428822964 ImageFile Hydroxyl aluminium bis 2 ethylhexanoate .png ImageSize 200px IUPACName OtherNames Hydroxyl aluminum bis 2 ethylhexanoate Aluminium 2 ethylhexanoate Aluminium 2 ethylcaproate Section1 Chembox Identifiers CASNo Ref cascite correct ?? CASNo 30745 55 2 PubChem SMILES Section2 Chembox Properties C 16 H 31 Al 1 O 5 Appearance Density MeltingPt BoilingPt Solubility Section3 Chembox Hazards MainHazards FlashPt Autoignition Hydroxyl aluminium bis 2 ethylhexanoate is a chemical substance derived from 2 Ethylhexanoic acid 2 ethylhexanoic acid and aluminium III . ref cite journal author Hershey, Harry C. McCauley, Victoria S. Kuo, Jeffrey T. McMillan, Michael L. title Solution properties of association colloids of twelve aluminum monohydroxy disoaps in nonaqueous solutions journal Journal of Colloid and Interface Science year 1984 volume 101 issue 2 pages 424 35 ref Nominally it is the coordination complex with the formula Al OH O sub 2 sub CCHEt CH sub 2 sub sub 3 sub CH sub 3 sub sub 2 sub where Et ethyl group ethyl . The composition is not a homogeneous compound. It is used as a thickening agent in various products, including in napalm . It is slightly hygroscopic. References reflist Category Aluminium compounds organic compound stub ja 2 ... more details
Hydroxyl terminated polybutadiene HTPB is a polymer of butadiene terminated at each end with a hydroxyl functional group . It reacts with isocyanate diisocyanate to form polyurethane , a stable and easily stored synthetic material. HTPB is a translucent liquid with a very similar color to wax paper, it is highly viscous. The properties cannot be precisely stated, because HTPB is manufactured in various grades to meet specific requirements. HTPB is thus a generic name for a class of compounds. It consists of many butadiene molecules linked together into a polymer forming polybutadiene. Both ends of the chain are terminated with a hydroxide ion OH , thus giving it the name Hydroxyl Terminated Polybutadiene. It is used in model rocketry as a high power fuel known commonly as RBS. It has also found its way into the pyrotechnics industry with a use as mortar tubes for aerial shell fireworks. It is insoluble in water making it a good sealant. Although it is used in rocket fuel it does not ignite easily it requires temperatures in excess of 773K to combust. The curing agent for it is usually a polyisocyanate compound. File 1,3 Butadiene Polymerization.PNG center Uses HTPB is used in many solid rocket motors to bind the fuel and oxidizing agent into a solid mass. It is also used as a hybrid rocket fuel. Together with N sub 2 sub O nitrous oxide , or laughing gas as the oxidizer, it is used to power the SpaceShipOne hybrid rocket motor developed by SpaceDev . ref cite web url http www.spacedev.com hybrid detail.php?id 1 title SpaceDev Hybrid Propulsion publisher SpaceDev ref It also powers all 3 4 stages of the Japanese M 5 rocket satellite launchers. JAXA describe the fuel as HTPB AP Al 12 68 20 which means, proportioned by mass, HTPB 12 binder and fuel , Ammonium perchlorate 68 oxidizer , and Aluminium powder, 20 fuel . References reflist External links http www.sartomer.com ... US Patent 5159123 synthesis of hydroxyl terminated polybutadienes using glycol ether Page ... more details
A triol is a chemical compound containing three hydroxyl groups OH functional groups , ref http www2.bakersfieldcollege.edu bmadani Lecturenote14 15.pdf Alcohols, Ethers, Thiols and Chirality ref such as glycerol . An example of triol on benzene is benzenetriol . See also Alcohols , chemical compounds with one hydroxyl group Diols , chemical compounds with two hydroxyl groups Polyols , chemical compounds with multiple hydroxyl groups Phenol , chemical compound with a hydroxyl group bonded to a benzene ring References Reflist chemistry stub Category Functional groups Category Polyols ... more details
A benzenetetrol is a type of chemical compounds formed with a benzene and four hydroxyl groups. It may refer to 1,2,3,4 Benzenetetrol 1,2,3,5 Benzenetetrol 1,2,4,5 Benzenetetrol Chemistry disambiguation Category Natural phenols ... more details
Unreferenced date December 2009 Orphan date December 2009 In organic chemistry a methylthiomethyl MTM ether is a protective group for Hydroxide hydroxyl groups . Hydroxyl groups are present in many chemical compounds and they must be protected during oxidation , acylation , halogenation , Dehydration reaction dehydration and other reactions to which they are susceptible. Many kinds of protective group s for hydroxyl groups have been developed and used in organic chemistry, but the number of protective groups for tertiary hydroxyl groups, which are susceptible to acid catalyzed dehydration , is still small because of their poor reactiveness. They can be easily protected with MTM ether s and recovered in good yield. To introduce an MTM ether to a hydroxyl group, two methods are mainly used. One is a typical Williamson ether synthesis using an MTM halide as an MTM resource and sodium hydride NaH as a base. The other is a special method, in which dimethyl sulfoxide DMSO and acetic anhydride Ac sub 2 sub O are used. In this case, the reaction proceeds with Pummerer rearrangement MTM ether s have another advantage. They are removed by neutral but toxic mercuric chloride , to which most other ethers are stable. As a result, the selective deprotection of polyfunctional molecules becomes possible using MTM ether s as the protective group s for their hydroxyl groups. DEFAULTSORT Methylthiomethyl Ether Category Thioethers Category Protecting groups ... more details
Image Hydroxyketone.svg right Hydroxy ketones A hydroxy ketone in organic chemistry is a functional group consisting of a ketone flanked by a alcohol hydroxyl group. In the two main classes the hydroxyl group can be placed in the alpha position an alpha hydroxy ketone RCR OH CO R or in the beta position a beta hydroxy ketone, RCR OH CR sub 2 sub CO R . An alpha hydroxy ketone is called an acyloin Prominent beta hydroxy ketones are aldol adduct s. Disamb sr Hidroksi keton ... more details
Refimprove date December 2009 Image beta D Glucopyranosyl.png 300px right thumb The &beta D glucopyranosyl group which is obtained by the removal of the hemiacetal hydroxyl group from &beta D glucopyranose A glycosyl group is a univalent free radical or substituent structure obtained by removing the hemiacetal hydroxyl group from the cyclic form of a monosaccharide and, by extension, of a lower oligosaccharide . Glycosyl also reacts with inorganic acid s, such as phosphoric acid , forming an ester such as glucose 1 phosphate . Examples In cellulose, glycosyl groups link together 1,4 beta D glucosyl units to form chains of 1,4 beta D glucosyl sub n sub . Another example is ribityl in 6,7 Dimethyl 8 ribityllumazine . Substituent groups other than glycosyl groups Image beta D Glucopyranos 3 O yl.png 300px right thumb The &beta D glucopyranos 3 O yl group which is obtained by the removal of a hydrogen from the C3 hydroxyl of &beta D glucopyranose Instead of the hemiacetal hydroxyl group, a hydrogen atom can be removed to form a substituent, for example the hydrogen off the hydroxyl on C3 of a glucose molecule. Then the substituent is called D glucopyranos 3 O yl ref http www.chem.qmul.ac.uk iupac 2carb 31.html ref as it appears in the name of the drug Mifamurtide . See also Acyl group References Reflist Category Substituents Category Biomolecules Category Monosaccharides Category Oligosaccharides Biochem stub ca Glucosil es Glicosil ja tr Glikosil zh ... more details
Multiple issues wikify January 2012 refimprove June 2011 An OH IR star is an Stellar evolution evolved late type star showing hydroxyl radical OH astrophysical maser maser emission which is bright at near infrared wavelengths. In Mira variable stars the outer atmosphere of the stars blows away as a strong wind and can be thrown off at the peaks of the pulsations. The gas in the circumstellar envelope condenses rapidly as it blows away from the star, forming molecules such as water and silicon monoxide . The SiO molecules combine to create Circumstellar dust grains of dust . The water molecules can be split by ultraviolet light from other stars to form hydroxyl radical hydroxyl molecules. The heat from the warm dust excites the hydroxyl. The excited hydroxyl molecules give rise to Astrophysical maser maser action in the lines at 1667 and 1612 MHz. Miras with short pulsation periods about one year and low mass loss rates produce weak masers in the 1667 MHz line. However, in Miras with a high mass loss rate and long pulsation periods up to six years , the 1612 MHz hydroxyl masers becomes much stronger than the 1667 masers. They produce a characteristic U shaped emission line shape from the shell of gas expanding away from the star. These stars are known as OH IR stars for their strong hydroxyl OH masers and strong infrared IR emission from the shell of warm gas. The intensity of the maser follows the changing brightness of the star as it pulsates. The difference in the velocities of the two peaks is equal to twice the velocity with which the shell of gas and dust given off by the star is expanding. A typical expansion velocity is about 20 km s 1. The left peak rises before the right peak and also falls before the right peak. This is a result of the extra time it take the radio waves to cross from the far side of the shell of masers to the near side. ref http www.peripatus.gen.nz Astronomy OHIRSta.html http www.peripatus.gen.nz Astronomy OHIRSta.html ... more details
Hydroxy can refer to In chemical nomenclature, the prefix hydroxy shows the presence of a hydroxyl functional group OH An abbreviation for the medication hydroxyzine , which is commonly sold under the brand names Atarax, Ucerax, Serecid, and Vistaril Hydroxy gas A nickname for oxyhydrogen , a combination of hydrogen and oxygen gas produced from the electrolysis of water disambiguation nl Hydroxy ... more details
Dideoxynucleotides , or ddNTPs, are nucleotide s lacking a 3 hydroxyl OH group on their deoxyribose sugar. Since deoxyribose already lacks a 2 OH, dideoxyribose lacks hydroxyl groups at both its 2 and 3 carbons. The lack of this hydroxyl group means that, after being added by a DNA polymerase to a growing nucleotide chain, no further nucleotides can be added as no phosphodiester bond can be created based on the fact that deoxyribonucleoside triphosphates which are the building blocks of DNA allow DNA chain synthesis to occur through a condensation reaction between the 5 phosphate following the cleavage of pyrophospate of the current nucleotide with the 3 hydroxyl group of the previous nucleotide. The dideoxyribonucleotides do not have a 3 hydroxyl group, hence no further chain elongation can occur once this dideoxynucleotide is on the chain. This can lead to the termination of the DNA sequence. Thus, these molecules form the basis of the Chain termination method dideoxy chain termination method of DNA sequencing , which was developed by Frederick Sanger in 1977. ref Sanger, F., Nicklen, S., and Coulson, A. R. DNA sequencing with chain terminating inhibitors. Proc Natl Acad Sci , 74 12 5463 7, 1977. ref Dideoxynucleotides are useful in the sequencing of DNA in combination with electrophoresis . A DNA sample that undergoes PCR polymerase chain reaction in a mixture containing all four deoxynucleotides and one dideoxynucleotide will produce strands of length equal to the position of each base of the type that complements the type having a dideoxynucleotide present. That is, each nucleotide base of that particular type has a probability of being bonded to not a deoxynucleotide but rather a dideoxynucleotide, which ends chain elongation. Thus, if the sample then undergoes electrophoresis, there will be a band present for each length at which the Complementary DNA complement of the dideoxynucleotide is present. It is now common to use fluorescent dideoxynucleotides such that each ... more details
the Milky Way. Most known extragalactic masers are megamasers, and the majority of megamasers are hydroxyl OH megamasers, meaning the spectral line being amplified is one due to a transition in the hydroxyl ... H sub 2 sub CO , and methine CH . Hydroxyl megamasers were the first type of megamaser discovered. The first hydroxyl megamaser was found in 1982 in Arp 220 , which is the nearest ultra luminous ... in hydroxyl megamasers are distinct from that of hydroxyl masers within the Milky Way , including the amplification of background radiation and the ratio of hydroxyl lines at different frequencies. The population inversion in hydroxyl molecules is produced by far infrared radiation that results ... . Zeeman splitting of hydroxyl megamaser lines may be used to measure magnetic field s in the masing .... 628 629. ref History In 1965, twelve years after the first maser was built in a laboratory , a hydroxyl ... for extragalactic masing was detection of the hydroxyl molecule in NGC 253 in 1973, and was roughly ... and NGC 1068 that was of comparable strength to the hydroxyl maser in Arp 220, and are as such considered ... were found in galaxies in which hydroxyl had been detected. Methine is seen in galaxies with hydroxyl absorption, while formaldehyde is found in galaxies with hydroxyl absorption as well as those with hydroxyl megamaser emission. ref name Baan1993 Baan1993 Baan 1993 ref As of 2007, 109 hydroxyl megamaser ... galaxy that hosts both of the two most common megamaser species, hydroxyl and water. ref name .... Hydroxyl megamasers Arp 220 hosts the first megamaser discovered, is the nearest ultraluminous ... of hydroxyl megamaser host galaxies, and is often used as a guide for interpreting other hydroxyl megamasers and their hosts. ref Elitzur1992Book Elitzur 1992 , pp. 308 310. ref Hosts and environment Image Galaxy arp 220.jpg left thumb 300px Image of Arp 220, the prototypical hydroxyl megamaser host galaxy, taken with the Hubble Space Telescope . Hydroxyl megamasers are found in the nuclear ... more details
wiktionary hydration Hydration may refer to Hydration reaction , a chemical addition reaction where a hydroxyl group and proton are added to a compound Mineral hydration , an inorganic chemical reaction where water is added to the crystal structure of a mineral Solvation , the clustering of solvent water molecules around a solute particle Tissue hydration , the supply and retention of adequate water in biological tissues See also Dehydration disambig es Hidrataci n ko it Idratazione sk Hydrat cia ... more details
Image Trimethyl steroid nomenclature.png thumb right Steroid skeleton. Carbons 18 and above can be absent. Hydroxycorticosteroids are corticosteroids that have an additional Hydroxyl hydroxy OH group. There are two main positions where the hydroxy are added at the 11, and at the 17. At the 11 position Image Corticosterone 2D skeletal.svg thumb Corticosterone a 11 hydroxycorticosteroid . 11 hydroxycorticosteroids include aldosterone corticosterone hydrocortisone At the 17 position Image Cortison.svg thumb Cortisone a 17 hydroxycorticosteroid . 17 hydroxycorticosteroids include cortisone hydrocortisone External links MedlinePlus 003459 Category Corticosteroids organic chem stub ... more details
Orphan date December 2008 An acylglyceride linkage is the covalent bond between the organic acid groups such as fatty acid and one of the three hydroxyl groups of glycerol . ref Moore, Randy, et al. 1998 Botany. 2nd Ed. New York WCB McGraw Hill. ISBN 978 0 697 28623 9 ref References references DEFAULTSORT Acylglyceride Linkage Category Chemical bonding biochem stub ... more details
DISPLAYTITLE tert Butyldiphenylsilyl tert Butyldiphenylsilyl , also known as TPS, is a protecting group for alcohol s. Its formula is C sub 16 sub H sub 19 sub Si . ref http www.organic chemistry.org protectivegroups hydroxyl tbdps ethers.htm ref gallery Image Tert Butyldiphenylsilyl.gif tert Butyldiphenylsilyl gallery References references DEFAULTSORT Butyldiphenylsilyl, tert Category Protecting groups org chem stub fr Tert butyldiph nylsilyle ... more details
Image Glycerine chemical structure.png thumb Glycerol Image Rasyslami.jpg thumb Fatty acid Image Triacetin.svg thumb Triacetin , the simplest possible fat Glycerides , more correctly known as acylglycerols , are ester s formed from glycerol and fatty acid s. Glycerol has three hydroxyl functional group s, which can be esterified with one, two, or three fatty acids to form monoglyceride s, diglyceride s, and triglyceride s. Vegetable oil s and animal fat s contain mostly triglycerides, but are broken down by natural enzyme s lipase s into mono and diglycerides and free fatty acids. Soap s are formed from the reaction of glycerides with sodium hydroxide . The product of the reaction is glycerol and salts of fatty acids. Fatty acids in the soap emulsion emulsify the oils in dirt, enabling the removal of oily dirt with water. Partial glycerides are esters of glycerol with fatty acids, where not all the hydroxyl groups are esterified. Since some of its hydroxyl groups are free the molecule is Chemical polarity Large molecules with both a polar and a non polar end polar . Short chain partial glycerides are more highly polarized, and have excellent solvent properties for many hard to solubilize drugs. ref http www.sasolos.com products pdf Excipients Pharmaceuticals.pdf Sasol Olefins & Surfactants Excipients for Pharmaceuticals. Partial glycerides page 10 ref References references Category Lipids Glycerides da Glycerid de Acylglycerine es Acilglic rido eo Glicerido fa fr Acylglyc rol gl Acilglic rido ko id Gliserida it Gliceridi he nl Glyceride pl Acyloglicerole ro Gliceride sr Glicerid fi Glyseridi sv Propantriol ... more details
Unreferenced date December 2009 Orphan date February 2009 A Thiacalixarene is a macrocycle or Cyclic compound cyclic oligomer based on a condensation product of a phenol derivative and sulfur. The word thiacalixarene is derived from thia as sulfur and calixarene . Thiacalixarenes have hydrophobic cavities that can hold smaller molecules or ions and belong to the class of cavitand s known in Host guest chemistry . Thiacalixarene IUPAC nomenclature nomenclature is straightforward and involves counting the number of repeating unit s in the ring and include it in the name. A calix 4 arene has 4 units in the ring and a calix 6 arene has 6. Synthesis Thiacalixarenes are synthetized using phenol derivatives and sulfur. The chemical reaction ranks under electrophilic aromatic substitution s followed by an elimination of water and then a second aromatic substitution. The reaction is base chemistry base catalysed . Calixarenes are difficult to separate because it is all too easy to end up with complex mixtures of linear and cyclic oligomers with different numbers of repeating units. With finely tuned starting materials and reaction conditions synthesis can also be surprisingly easy. image Thiacalixarene.png center generic thiacalix n arene structure Structure Thiacalixarenes, like calixarene are characterised by a three dimensional basket vase or chalice shape . In thiacalix 4 arene derivatives, the internal volume is around 10 cubic nanometer s. Thiacalix 4 arenes are characterised by a wide upper rim and a narrow lower rim . With phenol as a starting material, the 4 hydroxyl groups are intrannular on the lower rim. The basket form cone conformation is stabilized by hydrogen bond ing between the four hydroxyl group. In case of substituted hydroxyl group, other conformers can be observed, like 1,2 or 1,3 alternate. image PtertbutylthiacalixareneStructure.png center p tert butylthiacalix 4 arene crystal structure a methanol molecule is hosted in the cavity . Category Macrocycl ... more details
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