a)
Interpretation:
Assuming that halogens add to
Concept introduction:
Alkynes when treated with one equivalent of a halogen yield a dihaloalkene as the product. They react with two equivalents of the halogens to yield a tetrahaloalkane derivative. In the first step of the addition reaction the nucleophilic attack of the π electrons of the double/triple bond in alkene/alkyne on a halogen results in the formation of a cyclic halonium ion with the simultaneous elimination of a halide ion. In the second step the halide ion attacks the cyclic halonium ion to yield the product.
To propose:
A mechanism and to predict the product(s) expected for the reaction in which two equivalents of Br2 adds to 2-butyne assuming that bromine adds to alkynes in the same manner as they add to alkenes.
b)
Interpretation:
Assuming that halogens add to alkynes in the same manner as they add to alkenes, a mechanism is to be proposed and the product(s) expected for the reaction in which two equivalents of Cl2 adds to 1-phenylpropyne is/are to be predicted.
Concept introduction:
Alkynes when treated with one equivalent of a halogen yield a dihaloalkene as the product. They react with two equivalents of the reagents to yield a tetrahaloalkane as the product. In the first step of the addition reaction, the nucleophilic attack of the π electrons of the double/triple bond in alkene/alkyne on a halogen results in the formation of a cyclic halonium ion with the simultaneous elimination of a halide ion. In the second step the halide ion attacks the cyclic halonium ion to yield the product.
To propose:
A mechanism and to predict the product(s) expected for the reaction in which two equivalents of Cl2 adds to 1-phenylpropyne assuming that chlorine adds to alkynes in the same manner as they add to alkenes.
c)
Interpretation:
Assuming that halogens add to alkynes in the same manner as they add to alkenes, a mechanism is to be proposed and the product(s) expected for the reaction in which two equivalents of Br2 adds to 1-pentyne is/are to be predicted.
Concept introduction:
Alkynes when treated with one equivalent of a halogen yield a dihaloalkene as the product. They react with two equivalents of the reagents to yield a tetrahaloalkane as the product. In the first step of the addition reaction the nucleophilic attack of the π electrons of the double/triple bond in alkene/alkyne on a halogen results in the formation of a cyclic halonium ion with the simultaneous elimination of a halide ion. In the second step the halide ion attacks the cyclic halonium ion to yield the product.
To propose:
A mechanism and to predict the product(s) expected for the reaction in which two equivalents of Br2 adds to 1-pentyne assuming that bromine adds to alkynes in the same manner as they add to alkenes.
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Chapter 9 Solutions
OWLv2 with Student Solutions Manual eBook, 4 terms (24 months) Printed Access Card for McMurry's Organic Chemistry, 9th
- On the next page is an LC separation of the parabens found in baby wash. Parabens are suspected in a link to breast cancer therefore an accurate way to quantitate them is desired. a. In the chromatogram, estimate k' for ethyl paraben. Clearly indicate what values you used for all the terms in your calculation. b. Is this a "good" value for a capacity factor? Explain. c. What is the resolution between n-Propyl paraben and n-Butyl paraben? Again, indicate clearly what values you used in your calculation. MAU | Methyl paraben 40 20 0 -2 Ethyl paraben n-Propyl paraben n-Butyl paraben App ID 22925 6 8 minarrow_forwardd. In Figure 4, each stationary phase shows some negative correlation between plate count and retention factor. In other words, as k' increases, N decreases. Explain this relationship between k' and N. Plate Count (N) 4000 3500 2500 2000 1500 1000 Figure 4. Column efficiency (N) vs retention factor (k') for 22 nonionizable solutes on FMS (red), PGC (black), and COZ (green). 3000 Eluent compositions (acetonitrile/water, A/W) were adjusted to obtain k' less than 15, which was achieved for most solutes as follows: FMS (30/70 A/W), PGC (60/40), COZ (80/20). Slightly different compositions were used for the most highly retained solutes. All columns were 50 mm × 4.6 mm id and packed with 5 um particles, except for COZ, which was packed with 3 um particles. All other chromatographic conditions were constant: column length 5 cm, column j.§. 4.6 mm, flow rate 2 mL/min, column temperature 40 °C, and injection volume 0.5 μL Log(k'x/K'ethylbenzene) FMS 1.5 1.0 0.5 0.0 ཐྭ ཋ ཤྩ བྷྲ ; 500 0 5 10…arrow_forwardf. Predict how the van Deemter curve in Figure 7 would change if the temperature were raised from 40 °C to 55 °C. Figure 7. van Desmter curves in reduced coordinates for four nitroalkane homologues (nitropropane, black; nitrobutane, red; nitropentane, blue; and nitrohexane, green) separated on the FMS phase. Chromatographic conditions: column dimensions 50 mm × 4.6 mm id, eluent 30/70 ACN/water, flow rates 0.2-5.0 mL/min, injection volume 0.5 and column temperature 40 °C. No corrections to the plate heights have been made to account for extracolumn dispersion. Reduced Plate Height (h) ° 20 40 60 Reduced Velocity (v) 8. (2) A water sample is analyzed for traces of benzene using headspace analysis. The sample and standard are spiked with a fixed amount of toluene as an internal standard. The following data are obtained: Ppb benzene Peak area benzene Peak area toluene 10.0 252 376 Sample 533 368 What is the concentration of benzene in the sample?arrow_forward
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- Normalized Intensity (a. u.) 0.5 1.0 A 3D-printed GC column (shown below) was created for use with "micro" gas chromatography applications. To prove its utility, it was used to separate a mixture of alkanes (C9-C18, C22, C24). For the separation shown below, the column temperature was ramped from 40 °C to 250 °C at a rate of 30 °C per minute. (a) 9 10 = 1 mm 12 13 15 22 0.0 0 100 200 300 400 Time (sec) a) What detector would you use for this analysis? Justify your selection. b) Explain how the chromatogram would change if the separation was run isothermally. c) Explain how the chromatogram would change if the temperature ramp were increased to 50 °C per minute.arrow_forwardDevise a synthesis of each compound from the indicated starting material. You may also use any organic compounds with one or two carbons and any needed inorganic reagents. a. Brarrow_forwardPlease help me with #2b & #3 using the data.arrow_forward
- Heparin is used as an anti-coagulant. A risk of heparin use is thrombocytopenia, or low platelet count. This risk is minimized with the use of low molecular weight heparins (LMWH), therefore it is desirable to separate LMWH from higher molecular weight heparins. The method of choice to do this is molecular exclusion chromatography. Below is a chromatogram from a molecular exclusion chromatographic run. Peaks ranging from A to J are clearly distinguishable. The heparin mixture that was analyzed had anywhere from 6 to 30 repeat units of monomer (where the heparin with 30 repeat units would be roughly five times the size of the heparin with six repeat units). a. Which letter most likely represents the peak with 6 repeat units given these heparin polymers were separated with molecular exclusion chromatography? b. Explain your reasoning describing the mechanism of retention in molecular exclusion chromatography. 100 80 60 60 Relative Abundance 40 40 E GH 20 20 B A 36 38 40 42 44 46 48 50 50…arrow_forwardHELP NOW PLEASE ! URGENT!arrow_forwardHELP NOW PLEASE ! URGENT!arrow_forward
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