Alkynes Flashcards

1
Q

ALKYNES

  • contains??
  • general formula
A

C≡C

Cn H2n-2

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2
Q

REAL LIFE EXAMPLE OF ALKYNES

used as fuel in oxyacetylene torches

A

acetylene

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3
Q

REAL LIFE EXAMPLE OF ALKYNES

a naturally occurring anti-viral, anti-fungal, and antibiotic compound

A

Thiarubine A

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4
Q

REAL LIFE EXAMPLE OF ALKYNES

contraceptive

A

norethynodrel

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5
Q

REAL LIFE EXAMPLE OF ALKYNES

antibiotic

A

mycomycin

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6
Q

REAL LIFE EXAMPLE OF ALKYNES

antifungal

A

terbinafine

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7
Q

REAL LIFE EXAMPLE OF ALKYNES

antiretroviral

A

efavirenz

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8
Q

REAL LIFE EXAMPLE OF ALKYNES

anticancer, and nematicide

A

phenylhepta-1,3,5-triyne

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9
Q

2 types of ALKYNES + their other name

+ meaning of their alt names
+ difference

A
  1. Terminal alkynes (monosubstituted) *C≡C is nasa pinakadulo so the C≡C as a whole only has 1 substituent attached
  2. Internal alkynes (disubstituted) *C≡C ay nasa gitna so the C≡C as a whole has 2 substituents, 1 per C, attached
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10
Q

PALATANDAAN in naming ALKYNES
in terms of:

  • suffix
  • parent chain (straight-chain) [2]
A
  • -yne
  • longest chain that passes thru BOTH C ATOMS in the triple bond (with the triple bond carbons having the lowest number)
  • indicate position of triple bond before the parent name
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11
Q

ARANGE the ff in terms of stability and energy:

  • alkenes
  • 3 types of dienes
  • 2 types of alkynes
A

MOST STABLE (lowest energy)

  1. conjugated dienes
  2. alkenes
  3. isolated dienes
  4. internal alkyne
  5. terminal alkyne
  6. cumulated dienes

LEAST STABLE (highest energy)

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12
Q

PHYSICAL PROPERTIES of ALKYNES

in general, are similar to ____ and ____

A

alkanes and alkenes

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13
Q

ALKYNES have slightly ______ BP & MP than alkenes

A

higher

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14
Q

WHICH will exhibit a higher BP and MP?

  • linear
  • branching
A

linear

*more branching = bp lowers

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15
Q

2 WAYS of preparing alkynes

A
  1. Industrial Preparation
  2. Laboratory Preparation
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16
Q

PREPARATION of ALKYNES - INDUSTRIAL

  • 2 ways?
  • what is formed?
A

ALKYNES formed from

  1. Carbides
  2. Methane
17
Q

PREPARATION of ALKYNES - LABORATORY

  • what is formed?
  • ^^ how (2)?
A

alkynes from vicinal or geminal dihalides

18
Q

PALATANDAAN in reactions in alkynes

A

mechanism is similar to alkenes, may exceptions or added info lang which is yung mga stated here

19
Q

ALKYNES have a _____ C≡C due to?

A
  • nucleophilic
  • loosely held π electrons that can be donated to an electrophile
20
Q

how MANY MOLES of reagent is necessary to convert an ALKYNE into a saturated product?

A

2 moles

saturated product = alkane

so 1 mole of reagent will break 1 π bond. since alkyne has 2 π bonds (triple bond), it would need 2 moles.

21
Q

4 REACTIONS of ALKYNES

A
  1. Hydrogenation
  2. Electrophilic Addition
  3. Acetylide ion Formation
  4. Oxidative Cleavage
22
Q

HYDROGENATION

  • possible reagents (3)?
A

H2 or Na or Li

23
Q

WHAT IF 1 mole of reagent lang ang rineact sa alkyne?

A

magiging alkene yung product, rather than alkane + 1 substituent lang ang ma s-substitute PER C ATOM in the C≡C

IF, 2 moles kasi ang gamit, 2 substituents ang ma s-substitute PER C ATOM sa C≡C

24
Q

ELECTROPHILIC ADDITION - ADDITION OF HX

  • what do you call the main product?
A
  • geminal dihalide (2 halogen atoms are attached to the same Carbon)
25
Q

ELECTROPHILIC ADDITION - ADDITION OF X2

  • stereochemistry?
A
  • anti-addition pa rin kahit na 2 mols ang gamitin
26
Q

DRAW the ff structures as requested by maam:

  1. Alkanes
  2. Alkenes
  3. Alkynes
27
Q

ELECTROPHILIC ADDITION - HYDRATION

  • reagents?
  • what atoms attach to the C≡C?
  • mechanism? + definition
A
  • H2SO4, H2O
  • H, O, and H
  • KETO-ENOL TAUTOMERISM - rapid interconversion of enol & keto isomers
28
Q

ELECTROPHILIC ADDITION - HYDRATION

  • TERMINAL vs INTERNAL alkynes (what will their product be?)

+ which of the 2 follows markovnikov?

A

TERMINAL - 1 keto only (follows markovnikov)

INTERNAL - 1 keto (double bond O is in first C in C≡C) + 1 keto (double bond O is in second C in C≡C)

29
Q

____ ALKYNES are more ___ than alkenes or alkanes due to a _____ ____ ____ character and a hybridization of ___

THIS MEANS THAT:

_____ %s = electrons are ___ to nucleus = more stable _____ charge = more ____ ____

A
  • TERMINAL
  • acidic
  • higher % s
  • sp
  • higher
  • closer
  • negative
  • acidic
30
Q

the _____ (or removal of substituent H+) of a TERMINAL alkyne leads to its _____ _____, an ____ ____, which is an excellent _____

A
  • deprotonation
  • conjugate base
  • ACETYLIDE ANION
  • nucleophile
31
Q

the reaction, Acetylide Ion Formation, is only applicable to what type of ALKYNES?

A

terminal alkynes

32
Q

ACETYLIDE ANION

  • strength of basicity/acidity?

+ reason

A

STRONG BASE

bc it is a conjugate base of ACETYLENE (H-C≡C-H), which is a very weak acid

33
Q

ACETYLIDE ION FORMATION

  • study sample rxn
34
Q

OXIDATIVE CLEAVAGE

  • reagents?
  • possible products (2)?
A
  • O3 with Zn, H3O+

1.) 2 carboxylic acids (internal)
2.) 1 carboxylic acid + 1 CO2 (terminal)

35
Q

TEST for analyzing ALKYNES

+ what type of alkynes is analyzed?
+ reagents
+ positive result

A

TOLLEN’S TEST for TERMINAL ALKYNES

  • terminal
  • ammoniacal or alcoholic AgNO3
  • formation of gray ppt of silver acetylide