how to separate butyric acid and hexane
If an emulsion is formed because the two layers have similar densities, try to alter the density of each layer to make them more different. Add about 10 mL of dichloromethane 2. After filtration, the broth was added into PEG at different concentrations to form the aqueous two-phase solution. After allowing the layers to separate in the funnel, drain the bottom organic layer into a clean Erlenmeyer flask (and label the flask, e.g. The Butyric acid will react with NaOH to produce sodium butyrate which will move to the aqueous phases where it will be more soluble. The mixture is cooled and subsequent portions of 1 ml of hexane and 2 ml of water added, vortex-mixed for 15 seconds, placed in a centrifuge, allowed to reach a speed of 3000 rpm, and then stopped immediately. The boiling points of hexane and toluene are only separated by 43 C, and simple distillation is best for mixtures of components with more than a 50 C separation in boiling points. To demonstrate, benzoic acid was refluxed in ethanol along with concentrated sulfuric acid in order to form ethyl benzoate (Figure 4.56a+b). What is the pH of butyric acid? We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. 0000030626 00000 n <>stream These cookies track visitors across websites and collect information to provide customized ads. To isolate, wash with brine (\(\times 1\)) if using diethyl ether or ethyl acetate, dry with a drying agent, and remove the solvent via rotary evaporator to leave the pure neutral component. 0000002169 00000 n Lower concentrations of \(\ce{HCl} \left( aq \right)\) are less hazardous, but increasing the volume of the aqueous layer by a large amount would affect the efficiency of subsequent extractions and filtering steps. A similar reaction occurs with phenols \(\left( \ce{PhOH} \right)\), and they too can be extracted into an aqueous \(\ce{NaOH}\) layer (Figure 4.58a). Is then recovered in the organic phase 21.7 gl of n-butyric acid which corresponds, taking into account the dilution brought by the solvent: aqueous phase ratio, to an extraction yield of 87.5% and 0 , 52 g.1 acetic acid, a yield of 28%. Withdraw the majority of the bottom layer by Pasteur pipette, and dispense into the container (Figure 4.37a). Instead use the first mixing method described. A TLC plate of the reaction mixture at 1 hour of reflux showed residual unreacted carboxylic acid (Figure 4.56c), which is not uncommon due to the energetics of the reaction. Acid-Base Extraction: Acid-base extraction is a technique that is widely used to separate organic compounds. A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material. An acid-base extraction can be used to extract carboxylic acids from the organic layer into the aqueous layer. These acids are also produced by the action of skin bacteria on human sebum (skin oils), which accounts for the odor of poorly ventilated locker rooms. Repeat for pH levels of 5.00 and 7.00. The solubility properties of carboxylic acids are substantially different than their corresponding carboxylate salts. A shorter puge off time can shorten the solvent tail - but if too short, with the cost of discrimination in the inlet. Alternatively, manually mix the layers using a pipette. Separation of a mixture of benzoic acid and cyclohexane is however possible using a wash with a base such as \(\ce{NaOH}\). The aqueous two-phase system was used to separate . 0000057458 00000 n Benzoic acid is only soluable in hot water so cool the mixture and the benzoic acid comes out of solution and can be filtered out with filterpaper. If large quantities of acid are present such that acidification would require too great a volume of \(2 \: \text{M} \: \ce{HCl} \left( aq \right)\), concentrated \(\ce{HCl} \left( aq \right)\) may be instead added dropwise. The best method for the separation of naphthalene and benzoic acid from their mixture is sublimation because it is applicable for those organic compounds which pass directly from solid to vapour state on heating and vice versa on cooling. In this flask, there should be roughly \(50 \: \text{mL}\) of dichloromethane from the two extractions. Be sure to first cool the aqueous solution in an ice bath before extraction if the acidification created noticeable heat. What does it mean to nominate candidates? View Seperation Of Butyric Acid And Hexane.pdf from SCIENCE 2381 at Glebe Collegiate Institute. The hydroxide, these electrons here, would deprotonate the phenol, giving you again the phenolate anion, along with the hexane in your organic layer. Close the stopcock on the separatory funnel and position an Erlenmeyer flask beneath the setup, in case it drips. The technique that I use is derived from the procedure published by Bannon et al in 1985, as part of their series on FA analysis. To separate the mixture place in a separating funnel, add NaOH the same volume make sure to shake well. This section descries common problems and solutions in extractions. Polymeric materials tend to rest between layers as solvent interactions are minimized at the interface. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. See Answer. Technique. A similar reaction occurs: \[\begin{array}{ccccccccccc} \ce{PhCO_2H} \left( aq \right) & + & \ce{NaHCO_3} \left( aq \right) & \rightarrow & \ce{PhCO_2Na} \left( aq \right) & + & \ce{H_2CO_3} \left( aq \right) & \rightleftharpoons & \ce{H_2O} \left( l \right) & + & \ce{CO_2} \left( g \right) \\ \text{Benzoic acid} & & & & \text{Sodium benzoate} & & & & & & \end{array}\]. If fine crystals form (which are quite common), they will clog the filter paper and interfere with adequate drainage. As an example, the instructions are written to extract an aqueous solution three times using \(25 \: \text{mL} \: \ce{CH_2Cl_2}\) each time (\(3 \times 25 \: \text{mL} \: \ce{CH_2Cl_2}\), Figure 4.30). Using a funnel, pour the liquid to be extracted into the separatory funnel (Figures 4.24b + 4.25). Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. Ashleyyy5403 Ashleyyy5403 02/09/2022 Chemistry High School answered expert verified If you had a mixture of butyric acid and hexane, how would you separate the two compounds?. Use slit tubing to cushion the separatory funnel in the ring clamp. Put about 20 cm3 of ether into it and gently swirl it so as to dissolve any p-toluidine droplets sticking on the walls. Label the flask (e.g. To separate the components, a water wash may be attempted to remove benzoic acid, but benzoic acid is not particularly water-soluble due to its nonpolar aromatic ring, and only small amounts would be extracted into the aqueous layer (Figure 4.54a). Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. "top organic layer" and "bottom aqueous layer"). The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". Remove the stopper (it won't drain otherwise). Conical vials and centrifuge tubes tend to be less airtight than separatory funnels, so there should be no need to vent the system during shaking unless \(\ce{NaHCO_3}\) or \(\ce{Na_2CO_3}\) solutions are used. To clean a separatory funnel, first rinse it with acetone into a waste container. 0000053591 00000 n 3 How do you separate benzoic acid and salt? If you had a mixture of butyric acid and hexane, how would you separate the two compounds? It's also the favored source of fuel for the cells lining the interior of the large intestine or colon. As an example, the instructions are written to extract an aqueous solution three times using \(25 \: \text{mL}\) diethyl ether each time (\(3 \times 25 \: \text{mL}\) diethyl ether). An occasional reason that only one layer forms in a separatory funnel is if there are large quantities of compounds present that dissolve in both solvents, for example if large amounts of ethanol are present, which dissolve well in both aqueous and organic solvents. Therefore, a solution of bicarbonate can be used to separate mixtures of phenols and carboxylic acids (Figure 4.58b). These cookies ensure basic functionalities and security features of the website, anonymously. Follow up with a brine wash (\(\times 1\)) if using diethyl ether or ethyl acetate, dry with a drying agent, and remove the solvent via rotary evaporator to leave the pure acidic component. What likely happened is that the wrong layer was added to the separatory funnel - for example the organic layer was unknowingly added instead of the aqueous layer. Drain the bottom organic layer into the flask used previously, where there should be roughly \(75 \: \text{mL}\) of dichloromethane from the three extractions. Who are the experts? There may be soap-like compounds or other emulsifying agents present that dissolve some of the components in one another. 0000003450 00000 n I am thinking maybe as you said splitless could help me. If only a small amount of solid is seen compared to the theoretical quantity, it is likely the compound is quite water-soluble, and filtration would lead to low recovery. How many members are in a public company? The invention relates to non-woven protein fibers and to methods for forming and producing the same. 0000008639 00000 n Then wash the funnel with soap and water at your benchtop. If no solid forms upon acidification (or if fine crystals or low quantity of solid forms), extract the acidic component back into an organic solvent (\(\times 3\)). - 1 stationary, 1 moving. Check out a sample Q&A here. To demonstrate, benzoic acid was refluxed in ethanol along with concentrated sulfuric acid in order to form ethyl benzoate (Figure 4.56a+b). The pictures in this section show a single extraction of methyl red (colored compound, Figure 4.21) from an aqueous solution (bottom layer) into \(25 \: \text{mL}\) of ethyl acetate (top layer). The pictures in this section show the extraction of \(2 \: \text{mL}\) of a mildly acidic aqueous solution containing a single drop of methyl red solution into \(2 \: \text{mL}\) of ethyl acetate. There should be a very thin layer of grease used to seal the stopcock and prevent freezing. As previously discussed, carboxylic acids can be extracted from an organic layer into an aqueous layer by shaking them with basic solutions, which converts them into their more water-soluble salts. Thus, before draining liquid from a separatory funnel, remove the stopper (Figure 4.27a). dichloromethane with highly basic or dense solutions) gently in the separatory funnel. 0000067199 00000 n Have you tried n-butanol esterification (catalyzed with either sulfuric acid or BF3) ? how to separate butyric acid and hexane. First (better) : use on-column injection and pentane as solvent. You can also attach an instructions file; (The linear velocity is important because you need to be in a reasonable range. The PEG was precipitated with an iodine solution and filtered. It is a colorless and oily liquid that is soluble in ethanol, water, and ether. H bonding most significant; of low molecular mass. Butyric acid makes up about half of these SCFAs. If this happens, there are several methods that might help you see the interface. This page titled 4.6: Step-by-Step Procedures For Extractions is shared under a CC BY-NC-ND license and was authored, remixed, and/or curated by Lisa Nichols via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. The cookie is used to store the user consent for the cookies in the category "Other. Pour the contents to be extracted into a conical vial, or a glass tube with a tapered end (e.g. If you had a mixture of butyric acid and hexane, how would you separate the two compounds?. The most common reason for having only one layer in a separatory funnel when there should be two (as in when the procedure tells you to "separate the layers"), is to have made a mistake. The mistake can be remedied as long as the layers have not yet been thrown away! Paste your instructions in the instructions box. 0000011928 00000 n 0 Your task: to separate these three compounds by taking advantage of differences in their acidity. Use a similar process as the isolation of the acidic component, except basify the solution using \(2 \: \text{M} \: \ce{NaOH} \left( aq \right)\) until it gives a pH of 9-10 as determined by pH paper. It is assumed that readers conducting this type of experiment are familiar with performing single and multiple extractions. If both glass and Teflon stopcocks are available, Teflon is a better choice as there is always a possibility that solvent can dissolve the grease used with glass stopcocks and contaminate the sample. We also use third-party cookies that help us analyze and understand how you use this website. Experts are tested by Chegg as specialists in their subject area. Place the separatory funnel upright in the ring clamp to allow the layers to fully separate. If a solid forms upon acidification of the ionic salt, it can be collected through suction filtration. Gently mix the two solutions using one of the following methods: Secure a cap firmly on the vial (Figure 4.36c+d) then invert and shake the tube for 10-20 seconds (Figure 4.35). The interface between the layers should settle rather quickly, often within 10 seconds or so. How would you separate a mixture of p toluic acid and p toluidine dissolved in ether? If you had a mixture of butyric acid and hexane, how would you separate the two compounds? how to separate butyric acid and hexane. Invert the funnel and shake gently for 10-20 seconds. 0000004382 00000 n A: The butyric acid can be extracted using a NaHCO3 aqueous solution using principal of extractions. Q: MCQ 47: Ethanoic acid (CH;COOH) is present in A. lemon B. orange C. vinegar D. grapes We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. %%EOF Emulsions are when tiny droplets of one layer are suspended in the other layer, resulting in no distinct interface between the two layers (Figure 4.33). 0000003005 00000 n You would dissolve the mixture in an organic solvent and then perform as many extractions as are necessary with an NaHCO3 aqueous solution in order to extract the butyric acid. The residual carboxylic acid can be removed from the desired ester product using an acid-base extraction in a separatory funnel. However, phenols are considerably less acidic than carboxylic acids, and are not acidic enough to react completely with \(\ce{NaHCO_3}\), a weaker base. Calculate the extraction efficiency if we extract a 50.00 mL sample of a 0.025 M aqueous solution of HA, buffered to a pH of 3.00, with 50.00 mL of hexane. Additionally, the sodium bicarbonate neutralizes the catalytic acid in this reaction. This strategy can be extended to other examples. A separatory funnel should never be used with a hot or warm liquid. Gently invert the funnel (Figure 4.26b), and swirl the mixture a little. In this situation, the best approach is to remove the troublesome compound (i.e. Extraction is the recovery of a substance from a mixture by bringing it . A minor film is not something to worry about because if a small amount does make it into the organic layer, a subsequent drying and filtration step will often remove it. How will you separate cinnamic acid and naphthalene? Examples include tert-butyl methyl ether, hexane, and dichloromethane. If using a glass stopcock (Figure 4.23c), it likely needs no further preparation. You'll get a detailed solution from a subject matter expert that helps you learn core concepts. Place the separatory funnel in a ring clamp attached to a ring stand or latticework. Legal. Hold the separatory funnel so that your fingers firmly cover the stopper. by phase separation assisted with 'salting out', what may be achieved by adding CaCl 2 or KCl up to saturation. The aqueous solution originally has a pink color, as the methyl red appears red in acidic solution (the aqueous solution was made from \(50 \: \text{mL}\) water, 5 drops of \(0.1 \: \text{M} \: \ce{HCl}\) and 5 drops of \(1\%\) methyl red indicator solution). The neutral component will be the "leftover" compound in the organic layer. How would you separate a mixture of p toluic acid and p toluidine? One is to hold the separatory funnel up to the light, or to shine a flashlight onto the glass (Figure 4.32b). Nonetheless, if an emulsion does form, there are some ways to attempt to clarify them: Microscale work involves the manipulation of less than \(300 \: \text{mg}\) of compound, and usually involves solvent volumes of \(5 \: \text{mL}\) or less. Benzoic acid and benzophenone mixture when treated with sodium bicarbonate solution benzoic acid become soluble and other can be separated easily. This method should only be used if large quantities of large-sized crystals are seen. You can change your solvent from hexane to petroleum ether. centrifuge tube). Allow the solution to sit for a period of time (even until the next lab period) if possible. "bottom aqueous layer"). Research suggests it may benefit your digestive health. If another extraction is to be done, return the bottom layer to the conical vial, add fresh solvent and repeat the extraction and separation. The chemical formula for butanoic acid is CH3CH2CH2COOH. Perform a single extraction using approximately \(25 \: \text{mL}\) of dichloromethane (\(\ce{CH_2Cl_2}\), an exact amount is not necessary), as described previously, with the following differences: As \(\ce{CH_2Cl_2}\) is prone to emulsions, invert the funnel and shake. The bad news is that the butylated sultion with sulfuric acid canno't readly separate from added Hexane to the tubes . longer chained butanoic acid; cheesy odour boiling point. As previously discussed, carboxylic acids can be extracted from an organic layer into an aqueous layer by shaking them with basic solutions, which converts them into their more water-soluble salts. Extracting Bases. The purpose of this experiment was to perform a two-base extraction, thereby separating an "unknown" mixture of benzoic acid, 2-naphthol, and naphthalene into its separate components and determining the percent composition of the mixture. Sodium salicylate is roughly 350 times more soluble in water than salicylic acid due to its ionic character (Figure 4.55), and it is rather insoluble in organic solvents such as diethyl ether. butyric acid (CH3CH2CH2CO2H), also called butanoic acid, a fatty acid occurring in the form of esters in animal fats and plant oils. As previously discussed, carboxylic acids can be extracted from an organic layer into an aqueous layer by shaking them with basic solutions, which converts them into their more water-soluble salts. And now we've learned how to do extractions. Return the separatory funnel to the ring clamp, and allow the layers to separate. To separate the components, a water wash may be attempted to remove benzoic acid, but benzoic acid is not particularly water-soluble due to its nonpolar aromatic ring, and only small amounts would be extracted into the aqueous layer (Figure 4.54a). A similar reaction occurs: \[\begin{array}{ccccccccccc} \ce{PhCO_2H} \left( aq \right) & + & \ce{NaHCO_3} \left( aq \right) & \rightarrow & \ce{PhCO_2Na} \left( aq \right) & + & \ce{H_2CO_3} \left( aq \right) & \rightleftharpoons & \ce{H_2O} \left( l \right) & + & \ce{CO_2} \left( g \right) \\ \text{Benzoic acid} & & & & \text{Sodium benzoate} & & & & & & \end{array}\]. Second : use split mode injection with at least 1:20 of split ratio, with 20 time loss of sensitivity. Due to low boiling point of methyl ester of butyric acid no focusing is possible into the top of GC column and peak is then very broad and mixed with solvent front. In the case of 1-(14)C-labelled butyrate, the appearance of radioactivity in the blood of injected mice is rapid and some of it is maintained for relatively long periods in different organs, mainly the liver.However, no precision can be given about the structure of . This of course may not be practical. So, what is your liner volume, what is your current purge off time, what kind of liner are you using, what is the oven temperature at injection - and ramps, and what is the carrier flow rate in ml/in? ways to separate mixtures of compounds. In a base acid becomes soluble and other become insoluble. If the funnel is shaken with more vigor it will likely settle into two layers (Figure 4.31b). It's also found in lower amounts in some foods. To do so, withdraw the entirety of the bottom layer and a small amount of the top layer into the pipette. Ethanol and butyric acid react to form ethyl butyrate with the elimination of water: EtOH + HBut ---> EtBut + H20 but as the reaction in the laboratory would be carried out in the presence of hot sulfuric acid (sucks up the water thus pushing the reaction to the right) I have some doubts as to how fast it would take place in cold beer, if at all, unless some enzyme catalyzes it. You can change your solvent from hexane to petroleum ether. The funnels are easy to break, so cushion the funnel in the metal clamp using pieces of slit rubber or plastic tubing (Figure 4.23d). The compound phenol is considered as a weak acid. Question: Spts) -Draw a flowchart to show how you separate a mixture of butyric acid and hexane. Perform a single extraction using approximately \(25 \: \text{mL}\) of diethyl ether (an exact amount is not necessary), as described previously, making sure to appropriately label each layer (e.g. leo1352 Posts: 38 . \[\begin{array}{ccccccc} \ce{PhNH_2} \left( aq \right) & + & \ce{HCl} \left( aq \right) & \rightarrow & \ce{PhNH_3Cl} \left( aq \right) & & \left( \text{or } \ce{PhNH_3^+} \ce{Cl^-} \right) \\ \text{Basic amine} & & & & \text{Ammonium salt} & & \end{array}\]. 1. Answer (1 of 2): All three compounds dissolve in organic solvents (like dichloromethane or diethyl ether) better than in water. In this flask, there should be roughly \(50 \: \text{mL}\) of diethyl ether from the two extractions. Further drain the bottom layer, stopping when the interface just enters the stopcock chamber (Figure 4.27d). The design of conical vials and centrifuge tubes allows for efficient separation of the layers through withdrawal of the. Consuming butyric acid in foods like ghee . 6 How do you separate a base from an acid? Cyclohexane would remain in the organic layer as it has no affinity for the aqueous phase, nor can react with \(\ce{NaOH}\) in any way. 0000005898 00000 n Isolation of a substance from animal or plant matter is another application of extraction, either to obtaining the compound for some end use (e.g . The precipitate is collected by filtration then recrystallized freom hot water. Want to see the full answer? In almost all preparative procedures, washing of the crude product is a necessary part of the isolation procedure. This cookie is set by GDPR Cookie Consent plugin. Legal. Isobutyric acid (2-methylpropanoic acid) is an isomer. In this experiment an acid-base extraction will be used to separate a mixture containing about equal parts of an unknown carboxylic acid and an unknown neutral compound. 0000007472 00000 n 4 How would you separate butyric acid and hexane? Butyric acid (/ b j u t r k /; from Ancient Greek: , meaning "butter"), also known under the systematic name butanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula CH 3 CH 2 CH 2 CO 2 H.It is an oily, colorless liquid with an unpleasant odor. The color (methyl red), is extracted from the aqueous layer (bottom) into the ethyl acetate layer (top). A procedural summary of the first two extractions is in Figure 4.29. If large quantities of acid are present such that acidification would require too great a volume of \(2 \: \text{M} \: \ce{HCl} \left( aq \right)\), concentrated \(\ce{HCl} \left( aq \right)\) may be instead added dropwise. If a solid forms upon acidification of the ionic salt, it can be collected through suction filtration. Salts and esters of butyric acid are known . One difference in using the base \(\ce{NaHCO_3}\) instead of \(\ce{NaOH}\) is that the byproduct carbonic acid \(\left( \ce{H_2CO_3} \right)\) can decompose to water and carbon dioxide gas. Once separated, the salt from Aspirin would have to be acidified using HCL and then precipitated . The organic solvent must also be volatile (easily-evaporated) so it can be easily removed by . One difference in using the base \(\ce{NaHCO_3}\) instead of \(\ce{NaOH}\) is that the byproduct carbonic acid \(\left( \ce{H_2CO_3} \right)\) can decompose to water and carbon dioxide gas. A small amount of insoluble film between two layers is not uncommon during an extraction. Transfer this ether also to the separatory funnel. As has been discussed previously, the acid-base properties of compounds can be utilized to selectively extract certain compounds from mixtures. You will use a chemically active extraction to convert the water insoluble benzoic acid into its water soluble salt by treating the carboxylic acid with base. However, if the mixture contains a desired compound that can react with \(\ce{NaOH}\), a milder base such as sodium bicarbonate should be used. but I have to separate butyric acid from my solvent and it's been a reall problem for me. 0000006601 00000 n startxref The boiling point of cyclohexane is _______C and the boiling point of toluene is _________C. This strategy can be extended to other examples. Basic compounds such as amines can be extracted from organic solutions by shaking them with acidic solutions to convert them into more water-soluble salts. If using a conical vial, the volume markings on the glass may be helpful. As these containers are prone to tip, use a beaker (Figure 4.36a) or inverted cork ring (Figure 4.36b) for support. I am using DB-WAX 30m for the time being. Extraction of the product from the reaction mixture is also sometimes necessary as a means of separating it from the other components. What does it mean that the Bible was divinely inspired? This page titled 4.8: Acid-Base Extraction is shared under a CC BY-NC-ND license and was authored, remixed, and/or curated by Lisa Nichols via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. Find the formal concentration of butanoic acid in each phase when 100.0 mL of 0.10 M aqueous butanoic acid is extracted with 25.0 mL of benzene at a pH of 4.00. And carrier flow rate is an important consideration in selecting purge off time.). if using \(100 \: \text{mL}\) aqueous solution, extract with \(33 \: \text{mL}\) organic solvent each time). If only a small amount of solid is seen compared to the theoretical quantity, it is likely the compound is quite water-soluble, and filtration would lead to low recovery. The Salt can then be recovered by boiling the water until there is none left. The aqueous layer may be later acidified with \(\ce{HCl} \left( aq \right)\) if desired to convert the benzoic acid back to its neutral form. leo1352 Posts: 38 Joined: Sat May 29, 2010 4:42 am. Also obtain a stopper (Teflon or ground glass) that fits well in the top joint of the funnel (Figure 4.23a). Emulsions can happen for several reasons: Emulsions can be very difficult to rectify, and it's best if they are avoided in the first place by shaking solutions that are prone to emulsions (e.g. This problem has been solved! Question. Subscribe to our eNewsletter with daily, weekly or monthly updates: Food, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry. \[\begin{array}{ccccccccc} \ce{PhCO_2H} \left( aq \right) & + & \ce{NaOH} \left( aq \right) & \rightarrow & \ce{H_2O} \left( l \right) & + & \ce{PhCO_2Na} \left( aq \right) & & \left( \text{or } \ce{PhCO_2^-} \ce{Na^+} \right) \\ \text{Carboxylic acid} & & & & & & \text{Carboxylate salt} & & \end{array}\].