real world of indwtrial chemi~try
edited by
K. E. KOLB Bradley University Peoria, IL 61625
HAROLD
WITTCOFF
Chem Systems. internationai. Ltd. 28 St. James Square London SWlY 4JH. England
The Second 50 Industrial Chemicals, Part 2 Philip J. Chenier' and Danette S. Artibee University of Wisconsin-Eau Claire, Eau Claire, WI 54702
In a previous paper,2 we have described the second 50 chemicals list in analogy to the top 50 chemicals made in the United States arranged by amount produced and published yearly in Chemical and Engineering News.3 Part 1summarized some general characteristics of the second 50 chemicals, including production, price, growth, raw materials, and chemical relationshins. The first naner . . also discussed the individual manufacture and uses of rhemirals 51-75 of that list.'l'he present work will coml~lett.this study by presenting the inlpurtant manufucture and uses ofrhernirals 76 100. A c o ~ n ~ l elist r e of referenres that were ronsulted for this study is gi;en in the first paper. Manulaclure and Uses 76, Perchloroethylene (perc)
C,H,Cl,
+ C,HCI,
-
C,HCI,
+ 2HCl+ C,CI,
(perc)
There are three processes used in the making of perchloroethylene. Approximately 85% of the manufacture is from ethylene dichloride, as shown above. Perchloroethylene and trichloroethylene are produced in a single-stage oxychlorination process from ethylene dichloride and chlorine. The other 15% comes either from the chlorination of hydrocarbons (propane, for example) or from acetylene and chlorine via trichloroethylene.
The main use of perchloroethylene is in dry cleaning and textile processing (53%); other uses are as a chemical intermediate (28%) and in industrial metal cleaning (10%).
CH3-CHCI,
+ CI,
-
CH,-CC1,
+ HCI
l,l,l-Trichloroethane is made primarily from vinyl chloride by the hydrochlorination~hlorination(60%) process shown above; however, it may also he made from vinylidene chloride hv hvdrochlorination (30%)or from ethane by chlorination (i0%). Uses of l,l,l-trichloroethane are in cold cleaning (41901, vapor degreasing (22701, adhesives (17%), and electronics (6%). 78, Linear Alkylbenzenes (LAB)
' Author to whom correspondence should be addressed.
For Part 1 see Chenier, P. J.; Artibee, D. S. J. Chem. Edoc. 1988,
64. 244.
Reisch. M. S. Chem. Eng. News 1987, (April 13).20-23.
Volume 65
Number 5
May 1988
433
Linear alkylbenzenes are made from n-paraffins (C10-C14) by either partial dehydrogenation to olefins and addition to benzene with H F as catalyst (60%) or chlorination of the paraffins and Friedel-Crafts reaction with benzene and an aluminum chloride catalyst. The major uses of linear alkylhenzenes are in the manufacture of linear alkyl sulfonates, LAS (89%), which are divided into household detergents (74%)and industrial cleaners (15%). 79. Methyl Ethyl Ketone
Methyl ethyl ketone (MEK) is made by the dehydrogenation of sec-butyl alcohol in a process that is analogous to the production of acetone from isopropyl alcohol. About 81% of MEK is used in solvents. Coatings make up 7% of its use.
83. Dlethylene glycol
Diethylene glycol is produced as a byproduct in the manufacture of ethylene nlscol lrom hvdrolvsis of ethylene oxide. It is separated fromthe ethylend glycbl by vacuum distillation. Breakdown of diethylene glycol use is as follows: polyurethane and unsaturated polyester resins, 34%; triethylene glycol, 13%; antifreeze blending, 17%; morpholine, 8%; extraction solvent, 5%; natural gas dehydration, 4%; and textile agents, 3%. 84, Phosgene
Phosgene is manufactured by reacting chlorine gas and carbon monoxide in the presence of activated carbon. Uses of phosgene are restricted to polyurethanes (85%), herbicides (9%),and polycarbonates (6%). 85. Propylene Glycol n
2-Ethylhexanol is produced by aldol condensation of hutyraldehyde followed by reduction. Plasticizers account for 80% of the use of 2-ethylhexanol. About 10%goes toward the making of 2-ethylhexyl acrylate for adhesives and coatings. 81, Ethanolamines 0
/ \
CH2CHz + NH8 --r MEA + DEA + T E A where MEA represents monoethanolamine, HO-CHzCH2-NH2, DEA, diethanolamine, (HO-CHI-CHdzNH, and TEA, triethanolamine, (HO-CHz-CHhN. Ethanolamines are made bv reacting ethylene oxide and excess ammonia, followed by sipararion of &reacted ammonisand the three ethanolnmines. Ratioof the three products depends on reaction conditions. The breakdown of use of ethanolamines is as follows: detergents, 23%; natural gas conditioning and petroleum use, 20%; metal working, 8% textiles, 8%; agricultural intermediates and cement grinding aids, 7%; exports, 34%.
Propylene glycol is produced by hydration of propylene oxide in a process similar to that for the production of ethylene glycol by hydration of ethylene oxide. Polyester resins account for the majority of the commercial use of propylene glycol (45%). Other uses include pet food (12%), tobacco humectant (7%), cellophane (7'701, and food and pharmaceuticals (11%). 86, Methylene Chloride
CH,
+ C1,
+
CH3C1 CI,
-
+
CH3CI HCL CH2CI, + HCI
Methylene chloride is produced by the chlorination of methyl chloride, which in turn is made by the chlorination of methane. The main uses of methylene chloride are in paint remover (23%),aerosol sprays (20%),metal degreasing (a%),electronics (7%), and urethane foam blowing agents (5%). 87, Potassium Hydroxide
82, Sodium Chlorate
Sodium chlorate is readily produced in solution by the electrolysis of sodium chloride brine in a cell that is very similar to a diaphragm chlor-alkali cell, except that it has no diaphragm. By allowing the chlorine and sodium hydroxide to react to form hypochlorite and by providing an additional vessel where the cell liquor can he kept hot, the hypochlorite disnro~ortionatesto chloride and chlorate. ri~mbstall the sodium chloratc rnanufuctured iWDI)goes tu the n u l and ~ Dawr industry for blenchina. Other uses are in the'manufac&~;e of other chlorates, p&hlorates, and chlorites (8%) and of herbicides (2%). 434
Journal of Chemical Education
Potassium hydroxide is produced by the electrolysis of potassium chloride solutions. The breakdown of the use of potassium hydroxide is as follows: potassium carbonate, 25%; soaps, 7%; tetrapotassium pyrophosphate, 10%; other potassium compounds, 30%;and liquid fertilizers, 8%.
Commercial hexanes are produced by a two-tower distillation of straight-run gasolines that have been distilled from crude oil or natural gas liquids. Motor oil is themajor use of this chemical. I t isalso used as a solvent for oil-seed extraction and as a medium for various polymerization reactions.
89,Methyl Chloride
Di-
-
+ HCI CH3CI + H,O CH, + CI, CH,CI + HCI
CH,OH
(1) (2)
dimethylformamideand acetamide lauryl dimethylamine rubber chemicals mi~cellaneou~
50% 15% 15% 20%
Trc
The major method (65%) for the production of methyl chloride is by the reaction of methanol and hydrogen chloride, with the aid of a catalyst and either in the vapor or liquid phases (eq 1). Approximately 35% is made by the chlorination of methane (eq 2). The uses of methyl chloride are as follows: silicones, 38%; tetramethyllead, 38%; butyl rubber, 4%; methyl cellulose, 4%; herbicides, 4%; and quaternary amines, 3%.
The most significant of the alkylamines economically are the methylamines (146 million pounds). The ethylamines are made a t the 35-million-pound level, ethylenediamine a t 63 million pounds, isopropylamine a t 53 million pounds, and hutylamines a t 28 million pounds.
90, Methylene Diphenyl Diisocyanate (MDI)
93, Glycerin
choline chlwide (animal feed) miscellaneo~s
CI-CH-CH-CHz
'd'
+ NaOH + Hz0
I
OCOR HO-CH2-CH-CHS-0HJ
Aniline is condensed with formaldehvde: reaction with phosgene gives MDI. Rigid foams account for 75% of MDI use as polyurethanes. The nonpolymeric MDI is used in specialty urethanes for end uses in coatings, cast or injection-molded elastomers, and polyamides. 9 I, Butyl Acrylate
CH,=CH-CH,
CH,=CH-COOR + ROH + CO- Ni(CO)t HCI 0
CH,=CH-GOOH-
(3)
ROH + H+
ROH + NH3
-
RNH,
Mnnn-
insecticides surfactants misCellaneO~S
+ RCOO-Na+
(6)
Approximately 40% of glycerin comes from a synthetic process, the hydrolysis of epichlorohydrin (eq 5). The remaining 60% is made from fats as a byproduct of soap manufacture (eq 6). Major uses are drugs and toothpaste (20'701,tobacco (19%), cosmetics (15%),foods (13% alkyd resins (12%), polyether polyols for urethanes (8701, cellophane (4%), and explosives (1%).
Naphthalene is made by two commonly used methods. It is obtained by the distillation of coal tar recovered in the hyproduct coking of coal (60%). Alternatively, it may be produced from petroleum fractions high in methyl naphthalenes by hydrodealkylation a t high temperature and pressure in the presence of hydrogen, either with or without a catalyst (40%). Several uses of naphthalene include phthalic anhydride and 1-naphthyl n-methylcarhamate manufacture, insecticides, tanning agents, surfactants, and moth-proofing agents.
+ R,NH + R3N + H,O Oi.
Trl.
Methylamines are made by reacting methanol and ammonin in a cmtinuous-flow system, with n dehydration catalyst present. Separation of ""reacted raw materials and mono-, di-, and trisubstituted methylamines follows. Higher amines may be made using processes similar to that described for methylamines. Uses may be broken down for the methylamines as follows: Mono-
I
94, Naphthalene
Acrylates are still produced by a modified Reppe process that involves the reaction of acetylene, the appropriate alcohol (in the case of butyl acrylate, butyl alcohol is used), and carbon monoxide in the presence of an acid (eq 3). The process is continuous and a small amount of acrylates are made this way. The most economical method of acrylate production is that of the direct oxidation of propylene to acrylic acid, followed by esterification (eq 4). Acrylates find major use in coatings (45%),textiles (25%), and fibers, polishes, paper, and leather (15% collectively). 92.Alkylamines
4
+ NaOH + H20--r
RC00-CH2-VH-CH20COR MDI
CH=CH
95% 5%
1,4-Butanediol, also known as tetramethylene glycol, is produced by the hydrogenation of butynediol (eq 7 ) . Union Carbide has just announced a new process for making butanediol, along with tetrahydrofuran and y-butyrolactone, from maleic anhydride (eq 8). The major use of this chemical is in the manufacture of polyesters. Volume 65
Number 5
May 1988
435
96, Nonene
Originally made by the trimerization of propylene to give a branched nonene, this product now has limited use for detergents because of nonbiodegradability. Cracking and dehydrogenation of n-paraffins is now the preferred method, giving very linear chains. With good linear wax, an olefin product containing as much as 90% linear alpha olefins can be prepared. Nonene is used in the manufacture of nonvlohenol(30%) and ethoxylated nonylphenol nonionic surfa&nts. It is also used in the 0x0 process to make isodecyl alcohol (34%) for esters as plasticizers. 97, Dodecene
Like nonene, dodecene was originally made highly branchedvia oligimerization of propylene. Now it is made by cracking and dehydrogenation of n-paraffins (see nonene). Dodecene is used to produce dodecylbenzene (57%) and its sulfonate anionic detergent and, via the 0x0 process, is converted into tridecyl alcohol (16%) and ethoxylated nonionic surfactants. Dodecylphenol (12%) is also made into detergents.
98, Maleic anhydride
Maleic anhydride may either be made by the catalytic vapor-phase oxidation of benzene or the Cq hydrocarbon
stream. Both are responsible for 50% of maleic anhydride production in the United States, but the butane route is rapidly increasing because of new OSHA standards for benzene plants. Maleic anhydride use is as follows: unsaturated polyester resins, 51%; lube oil additives, 11%;fumaric acid, 10%; agricultural chemicals, 8%; copolymers, 5%; and malic acid, 4%.
99, Epichlorohydrin
Epicblorohydrin is produced by chlorohydrination of allyl chloride. Allyl chloride is obtained by chlorination of propylene. Uses of epichlorohydrin are for glycerin manufacture (30%) and epoxy resin manufacture (57%).
The steam-cracking of naphtha and catalytic cracking in the refinery produce the Ca stream, which includes butane, l-butene (butylene), cis- and tram-2-butene, isobutylene and butadiene. I-Butene can be separated by extracting the isobutylene with sulfuric acid and distilling the l-butene away from butane and butadiene. l-Butene is used in the alkylation of gasoline. It is also converted into butadiene, sec-butyl alcohol and methyl ethyl ketone, Cg derivatives by the 0x0 process, butylene oxide, polybutylene, and linear low-density polyethylene (requiring a small percentage of 1-butene). We thank Harold Wittcoff for comments and suggestions on the content of this paper.
Improved Multiple-Choice Examinations In high enrollment courses, such as General Chemistry,multiple-choice examinations are common became they save instructor time, are mschine-gradeable, and are considered to be objective. They are suitable for item analysis and for unequivocal grade assignment. However, design of a thougbt-provokingexamination requires carefully worked out choices to exclude guessing by simple answer recognition. All choices shown should look reasonable at first glance! In a wellprepared multiple-choice test the student should be compelled to solve the problem completely before being able to make a correct choice. However, the student should not be misled by closely related, yet wrong answers. Over the course of the last few years we have found and tried an improved technique. For numerical examination questions, all the correct choices (10-20 or more for i typical 50-min test) are collected in a common answer basket. Any given test may also contain matching or other descriptive exercises randomly interspersed with numerical problems. The only explanationa student needs isthat the correct choice for all numericalproblems is to be picked from the answer basket appearingat theendof theexamination.All valuesshown in theanswer basket are sorted from smallest to largesttogether with an appropriate number (-25%) of plausible decoys plus a last choice worded "None of these is correct within *I% relative error". The choices should be assembled in multiples of five and belabeled ABCDErepetitivelyif machine-grading is desired. From our experience, the results have been rewarding. Students actually solve the numerical problems before answering, are confident when the answer basket contains their solution, yet are unable to pick an answer by simple inspection and recognition. Best of all, significantlyless instructor time is required to write the improved multiple choice examination. Bernhard Binder Southern Oregon State College Ashland. OR 97520
436
Journal of Chemical Education
