Alkene to alkyne. The Alkyne Triple Bond.

Alkene to alkyne alkene-forming eliminations. The suffix ‘ane’ of the alkane is replaced by ‘ene’. Partial Reduction of Alkynes with Sodium in Liquid Ammonia. Park, M. The product of an addition reaction to an alkyne is an alkene – and, as we just mentioned, alkene reactions undergo addition reactions too. Treatment of a 1,2-dihaloalkane (called a vicinal dihalide) with an excess amount of a strong base such as KOH or NaNH2 results in a twofold elimination of HX and formation of an alkyne. This method is complementary to the Lindlar reduction because it produces trans rather than cis alkenes. As discussed in Section 1-9, the carbon-carbon triple bonds of alkynes are created by the the overlap of orbitals on two sp hybridized carbon atoms. Both hydrogen atoms are added to the same side of the alkyne as shown in the syn-addition mechanism for hydrogenation of alkenes in Preparation of Alkynes from Alkenes. Figure 9. This is a simple process using first halogenation of the alkene bond to form the dihaloalkane, and next, using the double elimination process to protonate the alkane and from the 2 Pi bonds. Alkynes are generally more reactive towards catalytic hydrogenation (e. For what it’s worth, I cannot find the first reaction (oxidation of diphenylacetylene to benzil with osmium tetroxide) on Reaxys. This two step methodology allows the preparation of terminal alkynes by one-carbon homologation of an aldehyde. A molecule with both an alkene and an alkyne will react with HBr at the alkene. Because the carbon-carbon π bond is relatively weak, it is quite reactive and can be easily broken and reagents can be added to carbon. 8. Also, he Each alkene has 2 fewer electrons than the alkane with the same number of carbons. The bromine reagent is in reddish color, and the product vicinal dibromide is colorless. Hydroamination mostly does Markovnikov addition of amines to alkenes and alkynes, and as mentioned in the article cited below, quote “The catalytic anti-Markovnikov addition of H-NR 2 to olefins was listed as one of the so-called “Ten Challenges Several effective strategies of catalyst design were developed to improve alkyne conversion, and alkene selectivity, for example, accelerating the formation of active hydrogen species, enhancing alkyne adsorption and suppressing the side reactions. Markovnikov’s rule restated In the addition of HX or H 2 O to an alkene, the more highly substituted carbocation is formed as the intermediate rather than the less highly substituted one. 5. identify the reagents, the alkyne, or both, needed to prepare a given ketone or a given cis alkene through a vinylic borane intermediate. Addition of hydrogen ( Reduction): When alkyne is heated with hydrogen in presence of Ni, Pt or Pd catalyst, alkane is formed. Alkyne-forming elimination reactions are described in a subsequent section. 5 for ·c-C 6 H 11) alkene reactions and mechanisms for questions 1-24, give the major organic product of the reaction, paying particular attention to regio- and stereochemical outcomes. When an alkene is protonated, the resulting carbocation is sp2 hybridized (33% s character) . Question: Substituted benzenes. Reply. Count in What are Alkynes? In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon-carbon triple bond. Both of the alkyne's pi bonds will undergo hydroboration if BH 3 (borane) is used by itself. Maybe this is better in English. Alkanes, or saturated hydrocarbons, contain only single covalent bonds between carbon atoms. The double bond of an alkene consists of a sigma (σ) bond and a pi (π) bond. As noted before, alkenes are hydrocarbons with carbon-to-carbon double bonds (R 2 C=CR 2) and alkynes are hydrocarbons with carbon-to-carbon triple bonds (R–C≡C–R). After all, shouldn’t the alkyne be more “exposed” than the alkene, less sterically hindered? Well, the 3-membered ring intermediate formed from alkynes and halogens has two properties which make it more unstable than the corresponding 3-membered ring intermediate formed from alkenes. While writing out the name of the molecule, arrange the substituents in alphabetical order. Odor : Odorless: Sweet smell: Odorless and colorless with exception of ethylene which has a slight odor. It bears two relatively acidic C-H bonds (pK a 25) and can therefore be “alkylated” (i. 3. The first step is comparable to a Wittig Reaction, and leads to a dibromoalkene. Even when an internal alkyne is prepared, an excess of sodium amide is often used to make sure the reaction goes to completion. An Na radical donates an electron to one of the P bonds in a carbon-carbon triple bond. The mechanism for this reaction involves successive single electron transfers from the metal (sodium or lithium) and proton transfers from When an electrophile such as HBr adds to an alkene, the reaction takes place in two steps and involves an alkyl carbocation intermediate. Catalysis Science & Technology 2022, 12 Converting copper sulfide to copper with surface sulfur for electrocatalytic alkyne semi-hydrogenation with water. Alkyne Hydrogenation. Question: Drawing alcohol formulas from names. For catalytic hydrogenation, the Pt, Pd, or Ni catalysts are so effective in promoting addition of hydrogen to both double and triple carbon-carbon bonds that the alkene intermediate formed by Because carbocations are involved as intermediates in these electrophilic addition reactions, Markovnikov’s rule can be restated in the following way:. the preparation of alkynes). We have already seen a little earlier that alkynes can be partially reduced to give an alkene using the Lindlar’s catalyst. For example, we can react alkyl halides with strong bulky and non-bulky bases to prepare the Zaitsev or Hofmann alkene: Preparation of Alkynes. 1) o hcl ch3oh 2) hcl ch3 3) hcl 4) hcl 5) hbr 6) hcl 7) ch3 h3o + 8) h3o + 9) h3o + 10) hg(oac)2, h2o nabh4 ch3 11) hg(oac)2, h2o nabh4. Palladised charcoal which is halfway deactivated is called as Lindlar’s Các alkene, alkyne là những hợp chất không có mùi và đều nhẹ hơn nước. Ở nhiệt độ thường, phần lớn các alkene và alkyne từ C2 đến C4 ở trạng thái khí, từ C5 trở lên ở trạng thái lỏng hoặc trạng thái rắn. Oxidation of 2 o alcohols to form ketones. Interestingly, it takes both hydrogens simultaneously! This choreography leads to the formation of a cis-alkene, highlighting the stereospecific nature of this reaction and its adherence to the syn addition pathway. Find out how to predict the regioselectivity and stereoselectivity of electrophilic addition reactions of alkenes. Question: Drawing alkyne formulas from names. identify the reagent and catalyst required to produce a given alkane or cis alkene from a given alkyne. Retro-Synthesis Further Reading. Alkynes. Thanks for adding this. An alkyne is a hydrocarbon with one or more carbon-carbon triple covalent bonds. identify the product formed from the reaction of a given alkyne with hydrogen and a specified catalyst. azide alkyne Huisgen cycloaddition to give triazoles. Alkynes can be reduced to trans-alkenes with the use of sodium dissolved in an ammonia solvent. o Two important groups also have common names; They are the vinyl and allyl groups. Acidity : Less acidic than alkene and alkyne. 1A) A variety of different types of substrates undergo elimination reactions to form alkenes, but many of these reactions have common features. While a plethora of active catalysts for the full hydrogenation of alkynes to alkanes have been developed, selective (3d) semi-hydrogenation catalysts have Here, we developed an alkyne-to-alkene chemical bond conversion way as the driving force to control ultrasensitive and instant reversible deformation of 2D carbon graphdiyne (GDY) film with an asymmetric interface During this mechanism an intermediate alkene is formed. For an alkene, drop –ane from the alkane name and replace with the suffix –ene. the hydration of a terminal alkyne—Section 9. This means that if our end goal is an alkane or alkene, we have the option of 8. As the name suggests, in these dehydration reactions, the leaving group halogen is removed with one hydrogen that is the β hydrogen. 10 E1 Elimination. Less acidic than alkenes. Question: Matching alcohols to their names I; Question: Alcohols: drawing formulas from names. When bromine is added to the sample, if the reddish color disappear, that means the sample does contain an alkene. In practice, it is difficult to isolate the alkene product of this reaction, though a poisoned catalyst—a catalyst with fewer available reactive sites—can be used to do so. Catalytic Hydrogenation of Alkenes. This post got me thinking; how do you pronounce "alkyne" (a hydrocarbon with a carbon-carbon triple bond) differently enough from "alkene" (a hydrocarbon with a carbon-carbon double bond) to differentiate the two in spoken conversation? Diborane reacts readily with alkynes, but the formation of substituted alkene products leaves open the possibility of a second addition reaction. Similarly, the staggered conformation of (2R,3R) or of (2S,3S)-2,3-dibromobutane (Figure 9. The “new” method we introduce in this section involves the reaction of an acid chloride with a diorganocopper reagent. If there are more than one of the same substituent use the prefixes di, tri, and tetra for two, three, and four substituents respectively. kasandbox. 1. As explained, since there is a bigger volume to an alkane than its corresponding alkyne (i. org are unblocked. The four main categories are (1) nucleophilic attack on an alkene alkyne, or allyl ligand and (2) insertion of the alkene into the metal-amide bond. Non-carbon reagents also undergo cyclization, e. org and *. Jon says: April 11, 2018 at 8:14 pm. Collectively, they are called unsaturated hydrocarbons Corey-Fuchs Reaction. Nature Communications 2021, 12 (1) . Figure 10. deprotonated to give its conjugate base, then treated with an alkyl halide) on either end giving either a mono-substituted (also known as a “terminal” alkyne) or di Primary alcohol formation from an anti-Markovnikov alkene hydration reaction (hydroboration-oxidation) is more likely than a substitution reaction. Step 2: Oxidation is the next step that occurs. Treatment with a lithium base (BuLi, LDA) generates a bromoalkyne intermediate via dehydrohalogenation, which undergoes metal-halogen exchange under the Plus, you’ll still have an alkyne functional group that you can then modify to fit your synthetic needs. Hybridizing the carbon so as to increase the s-character of the C-H increases the acidity, with the greatest change occurring for the sp-C-H groups found in terminal alkynes. Alkenes, represented by the formula CₙH₂ₙ, exhibit a planar The simplest alkene is ethene, the compound which has previously been called “ethylene”. Lindar’s catalyst has three components: Starting with an alkyne, partial reduction via Lindlar/H 2 will give you the cis alkene and reduction with Na/NH 3 will give the trans alkene. The most Hydrogenation of an Alkyne to a Cis-Alkene. Therefore, the water work-up is used in any case the protonate the alkynide ion and also quench the possible excess of NaNH 2. Lindlar’s Catalyst transforms an alkyne to a cis-alkene because the hydrogenation reaction is occurring on the surface of the metal. This is a simple process using first halogenation of the alkene bond to form the dihaloalkane, and next, using the double Learn about the structure, naming, stability and reactions of alkenes and alkynes, unsaturated hydrocarbons with double or triple bonds. The most common alkyl borane is the 9-BBN: You can find the mechanism of hydroboration-oxidation as well as acid-catalyzed-hydration and oxymercuration in this article on “ Hydration Reactions of Alkynes ”. Scheme 21: Aminoalkyne 1 undergoes cationic Pd-catalyzed hydroamination to afford enamine 2 Today Hank talks about the deliciousness of alkenes & alkynes, their structures, and how to remember which is which by simply knowing the alphabet. When an alkyne is protonated the resulting carbocation is sp hybridized (50% s character). That reaction gave us a cis-alkene. MasterOrganic. Alkynes can be prepared by the elimination of HX from alkyl halides in a similar manner as alkenes (Section 8. The intermediate alkene is converted to an alkyne by a second E2 elimination of a hydrogen and halogen. Common Features of Elimination Reactions (9. Drawing formulas from names. For example, 5-decyne gives trans-5-decene on treatment with lithium in liquid ammonia. Structures of alkene and alkyne are given. The Alkyne Triple Bond. The hydrogens are added in a trans fashion, not cis : The dehydrohalogenation of alkyl halides gives alkenes. identify the cis alkene produced when a given alkyne is reacted with borane followed by hot acetic o The simplest members of the alkene and alkyne series are frequently referred to by their older common names, ethylene, acetylene, and propylene. Unraveling high alkene selectivity at full conversion in alkyne hydrogenation over Ni under continuous flow conditions. It is transition and lanthanide metal catalyzed coupling of C and N atoms of an alkene/alkyne and amine to prepare a new amine. g. An organic molecule is one in which there is at least one atom of carbon, while a hydrocarbon is a molecule which only contain the atoms hydrogen and carbon. Summary. An alkyne can be reduced (hydrogenated) to an alkane using Pd/C, or reduced only to an alkene using Lindler’s catalyst (cis) or Na and NH 3 (trans). Sodium (Na) in solution with ammonia (NH3) will react with alkynes to form alkenes: This reaction adds a hydrogen to each carbon on the alkyne bond, reducing the bond to an alkene bond. Carey 5th Ed Online. This first process is gone over in much greater detail in the page on halogenation The initial product is an alkene, which undergoes the reaction successively to give alkane as the final product. Subsequent transfer of hydrogen to the adsorbed alkyne proceeds slowly, relative to the corresponding hydrogen transfer to an adsorbed alkene molecule. Alkenes, due to their reactivity and ability to form polymers, are widely used in the production of plastics, synthetic fibers, and elastomers. Carbon is unique in that it can form up to four bonds in a compound, so they The first practice problem is a summary of alkyne reactions followed by comprehensive synthesis practice problems, all the major classes of alkyne and alkene reactions are covered! These include the preparation dialkyl halides Alkyne to alkene conversion is carried out by the reduction of alkynes with hydrogen in the presence of palladised charcoal. Hydrogenation of an Alkyne to a Cis-Alkene. with the same number of carbons) the alkane should have a higher boiling point. Ethene is produced in large quantities because it is one of the most important substances for production of a wide variety of organic compounds and technological materials. kastatic. Alkenes will be more reactive toward HBr than alkynes. Structures of UV-activated alkyne–alkene [2 + 2] cycloaddition has served as an important tool to access cyclobutenes. The position of double bonds or side chains indicated by numbers 1, 2, 3 etc. S. Notice that in the alkene intermediate, the remaining hydrogen and halogen are anti to each other due to the stereoelectronic requirements of the E2 mechanism. If we can form alkenes through elimination reactions of alkyl halides, it’s natural to ask: can we also use elimination reactions to form alkynes? Perhaps through a reaction like this elimination of an alkenyl (aka vinyl) halide? The answer is yes! Although to be fair, these types of molecules [alkenyl halides] are See more The process begins with the electrophilic addition of a halogen to the alkene bond to form the dihaloalkane. The latter substances were discussed in Section 10. This page titled 25. Pd-C, H 2) than alkenes ; While it’s possible to partially hydrogenate an It is possible to completely reduce the alkyne to the corresponding fully-saturated alkane through the addition of two H 2 molecules. See the mechanism, examples and geminal dihalide definition. Pingback: Aerosols: Mechanisms of Mischief – Alkyne Reactions: Alkyne Reduction using Na and NH3. They are more acidic than alkanes and alkenes. Many alkynes have been found in nature. The reactions for the preparation of acetylene from calcium carbide are as shown below: CaCO 3 → CaO + CO 2 Deprotonation of functional groups such as OH and even alkyne C-H should hopefully be straightforward, but the use of bases to make alkenes may require some explanation. For an alkyne, drop –ane from the alkane name and replace with the suffix –yne. The alkyne to alkene reaction mechanism occurs in four steps, and this does not follow a catalytic mechanism: An electron breaks off sodium and attacks the carbon, forming a radical anion. , Lindlar’s Catalyst) at the transitional alkene stage. Internal alkynes can be reduced to trans-alkenes using Na in NH 3 (l); Under these conditions, terminal alkynes are not reduced as they deprotonate to give acetylide ions A more modern alternate set of reagents uses (1) Na / THF then (2) CH 3 OH; This reaction is stereospecific giving only the trans-alkene via It requires alkene or alkyne as substrate and can occur intermolecularly or intramolecularly. Typically uses Jones reagent (CrO 3 in H 2 SO 4) but many other reagents can be used. Internal alkyne can be converted into trans-alkene using sodium (or lithium) in liquid ammonia. These groups are used in common names. Figure \(\PageIndex{1}\): Mechanism of the lithium/ammonia reduction of an alkyne to produce a trans alkene. This reaction results in the formation of alkenes. The longest carbon chain containing the carbon-carbon double bond is selected as the parent alkene. Lindlar’s Catalyst transforms an alkyne to a cis-alkene. This is what is known as an elimination reaction, in that the elements H and Br (in this example) are removed in order to form the alkene. So what about the case where carbon has a double (alkene) or triple (alkyne) bond? You may already see the difficulty, following the VSEPR model, of attempting to bend another orbital around the carbon atom to form a second ? bond-such would bring electrons from different orbitals close to each other, increasing the energy of the system owing to strong repulsive forces. Although broadly adopted, the limitations with UV light as an energy source prompted us Both alkenes and alkynes find numerous applications in various industries. The University of Texas at Dallas Is this something that could be avoided through, say, a later-stage reduction of an alkyne to a cis or trans alkene (alkynes are generally slow to cleave with ozonolysis). M. Park, Synthesis, 2006, 3790-3794. Collectively, they are called unsaturated hydrocarbons because 8. Consequently, reduction of triple bonds occurs selectively at a moderate rate, followed by rapid addition of hydrogen to the alkene product. Question: Matching amines to their names Entrance of the Alkyne: As the main character, our alkyne molecule approaches, ready to pick up the hydrogens. Trans stereochemistry of the alkene product is established during the second reduction step (3) when the less-hindered trans vinylic anion is formed from the vinylic radical. , the ozonolysis of an alkene—Section 8. Alkenes vs. 12) hg(oac)2, ch3oh nabh 4 13) ch3 bh3 thf The main difference between Alkene and Alkyne is that alkenes contain at least one double bond between two carbon atoms, whereas alkynes contain at least one triple bond between two carbon atoms. He shows how alkynes can be synthesized from either geminal dihalides Rule 3. It is difficult to measure such weak acids, but estimates put the pK a of ethane at about 48. Ethene, the simplest alkene, is a key component in the production of polyethylene, one of the most commonly used plastics Contributors; Alkanes are undoubtedly the weakest Brønsted acids commonly encountered in organic chemistry. 10), specifically gives the (Z)-alkene by the anti-periplanar E2 elimination of a β-H and Br shown here. Lindlar's Catalyst: Hydrogenation of an Alkyne to a Trans-Alkene. If you're behind a web filter, please make sure that the domains *. Alkenes and alkynes are hydrocarbons characterised by carbon-carbon double and triple bonds, respectively, which confer distinct structural and reactive properties. Question: Drawing alkene formulas from names. As with the elimination of HX to form an alkene, we’ll defer a full Chad provides a thorough lesson on Alkyne Synthesis (i. Then the double E2 elimination process is used to form the 2 \(\pi\) bonds of an Learn how to convert alkenes to alkynes by halogenation and double elimination with sodium amide. write equations for the catalytic hydrogenation of alkynes to alkanes and cis alkenes. After numbering the longest chain with the lowest number assigned to the alkyne, label each of the substituents at its corresponding carbon. Alkanes vs. Alkynes are less reactive than alkene. The large difference of k alkene /k alkyne ratios observed for electrophilic radicals (36 for ·CF 3) versus nucleophilic radicals (3. Alkene formation in E1 reactions is not stereospecific. Because alkynes have two π bonds, diallyl boranes (R 2 BH) are often used to prevent the second addition of the boron to the boron-substituted alkene. By definition, alkenes are hydrocarbons with one or more carbon–carbon double bonds (R 2 C=CR 2), while alkynes are hydrocarbons with one or more carbon-carbon triple bonds (R–C≡C–R). The molecule acetylene (HCCH) is said to contain three sigma bonds and two pi bonds. Because hydrogenation is an interruptible process involving a series of steps, hydrogenation can be stopped, using modified catalysts (e. What happens when those respective alkenes are then subjected to a reaction known to be stereospecific, such as OsO 4 for the dihydroxylation of alkenes? For large-scale production of an alkyne, calcium carbide (CaC 2) is made to react with water. e. If you're seeing this message, it means we're having trouble loading external resources on our website. Friedel‑Crafts acylation—Section 16. Consider the illustrative example reaction in Scheme 21. If a double bond occurs twice or thrice in the parent chain the alkene is called diene or triene respectively. Furthermore, the advantages and disadvantages of various electrolyzers are systematically discussed. The charcoal used is moderately deactivated with the help of quinoline or sulphur compounds. identify the ketone produced when a given alkyne is reacted with borane followed by basic hydrogen peroxide. High degrees of chemoselectivity between alkyne and alkene are crucial criteria for competent catalysts. Quicklime is obtained by introducing limestone to heat. If HBr were to add by the same mechanism to an alkyne, an analogous vinylic carbocation would be The first practice problem is a summary of alkyne reactions followed by comprehensive synthesis practice problems, all the major classes of alkyne and alkene reactions are covered! Alkanes. The alkynes are unsaturated hydrocarbons that contain one triple bond, the general formula of alkynes C n H 2n-2 and the triple bond is known as the ‘acetylenic bond’. Parent alkyne is ethyne which is market known under the trade name “acetylene”. SE, but I think I'm more likely to get better responses here in the "industry" site. With a certain catalyst used, the hydrogenation of alkyne can be stopped at the alkene stage. If you feel it is difficult to understand such concepts Tutoroot online one-on-one tuition will help you a lot, our expert faculty will teach you the concepts that are really tough in Other specialized cycloadditions include multicomponent reactions such as alkyne trimerisation to give aromatic compounds and the [2+2+1]-cycloaddition of an alkyne, alkene and carbon monoxide in the Pauson–Khand reaction. Applying retro-synthesis, we work backwards from the alcohol to the alkene to the alkyne from an acetylide reaction that initially builds the carbon chain. Dr Mohamed El-Newehy NOMENCLATURE 6 The IUPAC Rules The addition of a hydroxyl group to an alkyne causes tautomerization which subsequently forms a carbonyl. Eg. This difference in bonding leads to variations in their chemical behavior and properties. Lastly, we will briefly look at how to prepare alkynes from alkenes. 3f. However, alkyne reacts with hydrogen in presence of palladium catalyst deposited over These concepts Alkane, Alkene, and Alkyne are the toughest concepts in chemistry, and these are important basics to crack IIT, NEET, or any other competitive examination. For example, in Figure 22. Late transition metal hydroamination catalysts have multiple models based on the regioselective determining step. 1). An unsaturated hydrocarbon is a hydrocarbon that contains less than the maximum number of hydrogen atoms that can possibly bond with the number of carbon atoms present. 8h Hydrogenation. , Lindlar’s Catalyst) at the transitional alkene Partial Reduction of Alkynes to cis Alkenes with the Lindlar Catalyst. [11] The reaction between C=C double bond and bromine (Br 2) can be used as a test for the presence of alkene in an unknown sample. 1 Alkene and Alkyne Overview. . In the presence of a catalyst—typically platinum, palladium, nickel, or rhodium—hydrogen can be added across a triple or a double bond to take an alkyne to an alkene or an alkene to an alkane. 4: Alkenes and Alkynes is shared under a CK-12 license and was authored, remixed, and/or curated by CK-12 Foundation via source content that was edited to the style and standards of An alternative method for the conversion of an alkyne to an alkene uses sodium or lithium metal as the reducing agent in liquid ammonia as solvent. Dissolving Metal Reduction of Alkynes Reaction Type: Addition. 9, which you might now wish to review. It is prepared by heating quicklime in the presence of coke. Kwon, J. Each of the carbon atoms in an alkane has sp 3 hybrid orbitals and is bonded to four other atoms, each of which is either carbon or Organic chemistry is the study of carbon compounds, so the study of organic chemistry is important because all living things are based on carbon compounds. Alkynes : Alkanes, alkenes, and alkynes are all organic hydrocarbons. alkene as the other groups on Cα and Cβ move into the alkene plane. Partial Reduction of Alkynes. Reduction of an ester, acid chloride or nitrile to form aldehydes. In fact, when using catalysts such as Pd (palladium) or Pt (platinum) the reaction cannot be stopped at the It’s very possible to selectively dihydroxylate an alkene in the presence of an alkyne; reactions with alkynes are much slower. This catalyst is robust, and highly active in many organic transformations including alkene and alkyne hydrogenation, carbon-carbon cross-coupling reactions, and aerobic alcohol oxidation. However, there's something else in play here: Alkynes, have a TRIPLE This catalyst is robust, and highly active in many organic transformations including alkene and alkyne hydrogenation, carbon-carbon cross-coupling reactions, and aerobic alcohol oxidation. C. 1 Alkene and Alkyne Overview By definition, alkenes are hydrocarbons with one or more carbon–carbon double bonds (R 2 C=CR 2), while alkynes are hydrocarbons with one or more carbon-carbon triple bonds (R–C≡C–R). Locate and assign a number to the slot position of the carbon-to-carbon double or triple bond. The C-C sigma bond of acetylene is formed by the overlap an sp hybrid orbital from each of the carbon atoms. qqztwb bmlsbx zwg bvc cvue bbdcka elx tbtxag hbtwqpf rmfp qntkgal rebmbce uok hoyh lpxgf