EOPS&T_-_Organic_Chemistry.pdf

Table of Contents

(Subject Area: Organic Chemistry)

Article

Authors

Pages in the

Encyclopedia

Acetylene

Robert J. Tedeschi

Pages 55-89

Alkaloids

Armin Guggisberg and

Manfred Hesse

Pages 477-493

Bioconjugate

Chemistry

Claude F. Meares

Pages 93-98

Carbohydrates

Hassan S. El Khadem

Pages 369-416

Catalysis,

Homogeneous

Piet W. N. M. van Leeuwen Pages 457-490

Fuel Chemistry

Sarma V. Pisupadti

Pages 253-274

Heterocyclic

Chemistry

Charles M. Marson

Pages 321-343

Organic Chemical

Systems, Theory

Josef Michl

Pages 435-457

Organic Chemistry,

Synthesis

John Welch

Pages 497-515

Organic Macrocycles

J. Ty Redd, Reed M. Izatt

and Jerald S. Bradshaw

Pages 517-528

Organometallic

Chemistry

Robert H. Crabtree

Pages 529-538

Pharmaceuticals,

Controlled Release of

Giancarlo Santus and

Richard W. Baker

Pages 791-803

Physical Organic

Chemistry

Charles L. Perrin

Pages 211-243

Stereochemistry

Ernest L. Eliel

Pages 79-93

Acetylene

Robert J. Tedeschi

Tedeschi and Associates, Inc.

I. Introduction

II. Acetylene and Commodity Chemicals

III. Production of Acetylene and Commodity

Chemicals

IV. Acetylene-Based Processes for Large-Volume

Chemicals

V. Important Chemical Uses for Acetylene

VI. Reppe Products

VII. Specialty Acetylenics and Derivatives

VIII. Processes for Acetylene Production

IX. Chemistry of Specialty Products

X. Vinyl Ethers

XI. Flavor and Fragrance Compounds and Vitamins

A and E

XII. Acetylenic Pesticides

XIII. Acetylenic Reactions with Research and

Commercial Potential

XIV. Acetylene Research in Russia

GLOSSARY

Carbonylation Reaction of acetylene with carbon

monoxide and alcohols to form acrylate esters; Reppe

process.

Commodity chemicals Large-volume, multitonnage

chemicals, some of which are derived from acetylene.

Ethynylation Reaction of acetylene with aldehydes and

ketones to form acetylenic alcohols and diols.

Grignard Organomagnesium halide used in acetylenic

and other syntheses.

Oil-well acidizing Use of acetylenic alcohols (alkynols)

as corrosion inhibitors to protect steel pipe during

acidizing operations undertaken to free oil from lime-

stone formations.

Pesticides Agricultural chemicals including herbicides,

insecticides, miticides, fungicides, and bacterial con-

trol agents.

Reppe products and technology Pioneered by Dr.

Walter Reppe of the I. G. Farben; various prod-

ucts derived from the reaction of acetylene with

Acetylenic Pertaining to organic compounds containing

a triple bond ( C C ) or acetylene group in the

molecule.

Adjuvant Acetylenic diol used with pesticides to en-

hance activity, lower the rate of application, and in-

crease safety.

Alkynol Primary, secondary, or tertiary acetylenic alco-

hol with the hydroxyl group generally adjacent or

the triple bond.

Ammoxidation Acrylonitrile manufactured by oxidation

of propylene in the presence of ammonia.

Aprotic Pertaining to highly polar solvents such as

dimethyl sulfoxide (DMSO), hexamethylphospho-

ramide (HMPA), N -methyl-pyrrolidone (NMP), and

acetonitrile that can hydrogen bond or complex with

acetylene and acetylenic compounds; used to dissolve

and activate acetylene.

Acetylene

formaldehyde to yield butyne-1,4-diol and propargyl

alcohol.

Surfynols Acetylenic hydroxyl compounds used as high-

speed, low-foam wetting–dispersing agents and as

agricultural adjuvants and formulation aids.

Troﬁmov reaction Formation of substituted pyrroles

and N -vinylpyrroles by reaction of acetylene with

ketoximes.

Vinylation Reaction of acetylene with alcohols or pyrol-

lidone to form vinyl ethers and vinylpyrrolidone.

lene burned in the presence of oxygen provided a very hot

ﬂame, useful in the joining of metals. The welding indus-

try today still uses signiﬁcant amounts of acetylene in spite

of the availability of less expensive fuels such as propane.

Initially, acetylene was handled in industry as the undi-

luted liqueﬁed gas below its critical temperature of 36 ◦ C

at a pressure greater than 600 psig. This appeared to be

a safe procedure until a series of industrial explosions

in the early 1900s eliminated the practice. Today acety-

lene is shipped in cylinders under pressure that contain a

mixture of diatomaceous earth or asbestos, acetone, and

stabilizers. Another safe method of transport is via granu-

lar calcium carbide in sealed containers, free of water. The

large-volume use of acetylene for the manufacture of com-

modity chemicals has led to the building of plants, either

petrochemical or calcium carbide, “across the fence” from

acetylene producers. Today the factors leading to acety-

lene hazards are well understood and have been well doc-

umented. Acetylene now poses a minimum risk in well-

operated processes and plants.

ACETYLENE CHEMISTRY is the chemistry of the

carbon–carbon triple bond ( C C ). This functionality

deﬁnes the unique chemistry of this reactive group, in ad-

dition to its diverse and important applications. The high

electron density of the triple bond with its circular, sym-

metrical

-carotene, pesticides, surfactants, cor-

rosion inhibitors, and specially intermediates. This article

describes the technology and applications of acetylene,

acetylenic compounds, and the chemicals derived from

them.

In the mid-1960s more than 1 billion pounds of

acetylene were used annually for the production of

large-volume (commodity) chemicals. Since then, acety-

lene has been gradually supplanted by less expensive

oleﬁn feedstocks. However, acetylene is still used in

multimillion-pound levels to produce Reppe chemicals

(butynediol, propargyl alcohol, butanediol, butyrolactone,

N -methylpyrrolidone, polyvinylpyrrolidone, and vinyl

ether copolymers) and specialty acetylenic chemicals and

their derivatives. Large volumes of butanediol are used in

the manufacture of engineering plastics such as polybuty-

lene terephthalate. Other signiﬁcant uses for acetylene in

specialty areas include acetylene black, vitamins A and E,

ﬂavor–fragrance (F & F) compounds, corrosion inhibitors,

acetylenic surfactants, and pesticides. Acetylenic chemi-

cals, polymers, and derivatives of potential value in re-

search and commerce are also discussed. Some special

aspects of acetylene chemistry research in Russia are also

summarized.

II. ACETYLENE AND COMMODITY

CHEMICALS

10% of this to-

tal. After 1970, the use of acetylene for the manufac-

ture of commodity chemicals began to decline markedly,

and by 1979–1983 only 269 million pounds were em-

ployed. Less expensive petrochemical raw materials such

as ethylene, propylene, butadiene, amylenes, and methane

were replacing acetylene . Table I summarizes chemicals

manufactured mainly from actylene before 1965, types of

processes, and replacement raw materials. The principal

use of the monomers listed in the table was in diverse

polymer applications spanning plastics, latex emulsions,

rubbers, and resins. Chlorinated solvents were important

in vapor degreasing, but their use in more recent years

has been gradually limited as a result of toxicity and air

pollution.

The applications of the polymer products derived from

the above monomers are not within the scope of this article.

∼

I. INTRODUCTION

III. PRODUCTION OF ACETYLENE AND

COMMODITY CHEMICALS

Acetylene has always been an important raw material for

making chemical products. In the early years of its history

(circa 1890–1900) it was used extensively as an illuminant

for trains and city streets. It was soon realized that acety-

The following tabulation shows the gradual decline in U.S.

acetylene production from its high point of 1.23 billion

pounds in 1965 to

ﬁeld makes acetylene and its derivatives reac-

tive and useful intermediates for synthesizing a wide va-

riety of organic compounds. These organic products ﬁnd

wide use in the synthesis of ﬂavors and fragrances, vita-

mins A, E, and K,

From 1965 to 1970 more than 1 billion pounds of acetylene

were used annually to manufacture a variety of chemi-

cals. Welding applications constituted

269 million pounds in 1979. In 1965

bulk acetylene was valued at 7–12 / /lb, while ethylene was

∼

Acetylene

TABLE I Early Acetylene-Based Chemicals

Product

C 2 H 2 process

Replacement raw material

Replacement process

Acrylates and acrylic acid

Reppe carbonylation (CO

C 2 H 2 )

Propylene (C 3 H 6 )

Two-stage oxidation

Acrylonitrile

C 2 H 2 +

HCN

C 3 H 6

Ammoxidation (C 3 H 6 –O 2 –NH 3 )

Chloroprene

C 2 H 2 -Vinylacetylene-HCl

Butadiene

Chlorination and dehydrochlorination

Chlorinated hydrocarbons

C 2 H 2 +

Cl 2

C 1 –C 3 feedstocks; C 2 H 4

Chlorination–dehydrochlorination

Vinyl acetate

C 2 H 2 +

acetic acid

Ethylene (C 2 H 4 )

Oxyacetylation

Vinyl chloride

C 2 H 2 + HCl

Ethylene

Oxychlorination

C 2 H 2 + HCl

C 2 H 2 + C 2 H 4

Balanced ethylene–acetylene

3–4 / /lb. By 1983–1984 the cost ratio was approximately

the same, with acetylene valued at about 55–75 / /lb and

ethylene at 23–29 / /lb.

tion is a mix from calcium carbide, by-product acetylene

from cracking, and partial oxidation processes.

The nine U.S. acetylene producers, with their capacity

in millions of pounds, were AIRCO-BOC, Calvert City,

KY, and Louisville, KY (75); Dow, Freeport, TX (16);

Hoffmann–La Roche, Nutley, NJ (5); Monochem,

Geismar, LA (180); Rohm and Haas, Deer Park, TX (55);

Union Carbide, Ponce, P. R. (12); Union Carbide; Seadrift,

TX (12); Taft, LA (10); Texas City, TX (16).

The 1984 demand for acetylene was 286 million

pounds, and it was estimated to be 292 million pounds in

1988. Growth from 1974 to 1983 was negative at

Year

C 2 H 2 used (10 6

lb)

1965

1230

1967

1065

1969

1195

1971

852

1973

571

1976

490

6.9%

per year, while through 1988 it was slightly positive at

0.5% per year. Hoffmann–La Roche generates acetylene

from calcium carbide for use in the manufacture of vita-

mins A and E and

−

1979

269

1984

286

From 1967 to 1974, 23 plants making such acetylene-

based products as acrylonitrile, chlorinated hydrocarbons,

chloroprene (neoprene), vinyl acetate, and vinyl chloride

were shut down. Sixteen of these plants manufactured

vinyl acetate and vinyl chloride. Table II p resents acety-

lene usage for various products in 1970, 1979, and 1984.

In 1984 total U.S. capacity for the production of acety-

lene was estimated to be 384 million pounds. This produc-

-carotene.

Of all the commodity chemicals listed in Table II ,

vinyl chloride showed the least decline from 1970 to

1984. In 1984 acetylene converted to vinyl chloride rep-

resented 51% of total acetylene consumption. However,

this production was from only one site, Monochem at

Geismar, LA, and may be vulnerable in the future if

Monochem decides to convert completely to ethylene as

raw material. The most promising growth areas for acety-

lene in the near term are Reppe chemicals, particularly

butane-1,4-diol, used extensively in engineering plastics

and polyurethanes. Acetylene black and vinyl ﬂuoride are

also specialty growth areas, as are acetylenic surfactants

and corrosion inhibitors. These acetylene-drived products

are discussed in greater detail in Section V.

TABLE II U.S Acetylene Usage: Large-Volume

Chemicals

Product

1970

1979

1984

Acrylic acid and acrylates

16–45 a

Acrylonitrile

Chloroprene (neoprene)

242

Chlorinated solvents

A. Acetylene Production on a World Basis

Vinyl chloride

268

100–110 a

146

Vinyl acetate

158

37–52 a

Table III shows that, although U.S. acetylene production

is modest, acetylene usage worldwide is still signiﬁcant,

amounting to

Reppe chemicals b

73–80 a

114

Other acetylenics and

1.9 billion pounds.

In the longer term, it is believed that worldwide acety-

lene capacity and usage will gradually increase as oil

prices escalate. Acetylene usage for such products as vinyl

acetate, vinyl chloride, Reppe chemicals, and specialty

∼

derivatives c

a Mainly butane-1,4-diol plus other Reppe products.

b Acetylene black, vinyl ﬂuoride, specialty acetylenics.

c Estimated value.

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