31:
203:
839:
When keeping the pH at a constant level but changing the buffer concentration a change in rate signals a general acid catalysis. A constant rate is evidence for a specific acid catalyst. When reactions are conducted in nonpolar media, this kind of catalysis is important because the acid is often not
834:
266:
are prepared by amination of alcohols, catalyzed by solid acids. In this role, the acid converts, OH, a poor leaving group, into a good one. Thus acids are used to convert alcohols into other classes of compounds, such as thiols and amines.
210:
In industrial scale chemistry, many processes are catalysed by "solid acids". Solid acids do not dissolve in the reaction medium. Well known examples include these oxides, which function as Lewis acids: silico-aluminates
497:
350:
547:
963:
Michael Röper, Eugen Gehrer, Thomas
Narbeshuber, Wolfgang Siegel "Acylation and Alkylation" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2000.
1024:
995:
95:
537:
acceleration. The strongest acids are most effective. Reactions in which proton transfer is rate-determining exhibit general acid catalysis, for example
122:
than the neutral carbonyl group itself. Depending on the chemical species that act as the acid or base, catalytic mechanisms can be classified as either
899:
Gómez Millán, Gerardo; Phiri, Josphat; Mäkelä, Mikko; Maloney, Thad; Balu, Alina M.; Pineda, Antonio; Llorca, Jordi; Sixta, Herbert (5 September 2019).
373:
295:
between solvent S and AH in favor of the SH species. This kind of catalysis is common for strong acids in polar solvents, such as water.
194:. In terms of mechanism, the carbonyl oxygen is susceptible to protonation, which enhances the electrophilicity at the carbonyl carbon.
984:
291:
of the protonated solvent molecules SH. The acid catalyst itself (AH) only contributes to the rate acceleration by shifting the
829:{\displaystyle {\text{rate}}=-{\frac {{\text{d}}}{{\text{d}}t}}=k_{1}{\ce { }}+k_{2}{\ce { }}+k_{3}{\ce { }}+...}
1060:
301:
947:
Busca, Guido "Acid
Catalysts in Industrial Hydrocarbon Chemistry" Chemical Reviews 2007, volume 107, 5366-5410.
151:
chemical reactions. Many acids can function as sources for the protons. Acid used for acid catalysis include
228:
35:
862:"Synthesis of sulfonated carbon catalyst from waste orange peel for cost effective biodiesel production"
168:
979:
Lowry, T. H.; Richardson, K. S., "Mechanism and Theory in
Organic Chemistry," Harper and Row: 1981.
292:
224:
164:
63:
30:
255:
183:
102:, H) donor and the base is the proton acceptor. Typical reactions catalyzed by proton transfer are
1065:
930:
881:
861:
538:
275:
Two kinds of acid catalysis are recognized, specific acid catalysis and general acid catalysis.
980:
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59:
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1005:
901:"Furfural production in a biphasic system using a carbonaceous solid acid catalyst"
900:
251:
119:
99:
62:
water (bottom left). Both lower the kinetic barrier and speed up the attainment of
51:
916:
1029:
1000:
877:
533:
In general acid catalysis all species capable of donating protons contribute to
259:
236:
202:
247:
156:
43:
1033:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
1004:, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "
968:
17:
1042:
1013:
860:
Lathiya, Dharmesh R.; Bhatt, Dhananjay V.; Maheria, Kalpana C. (June 2018).
492:{\displaystyle {\text{rate}}=-{\frac {{\text{d}}}{{\text{d}}t}}=k{\ce { }}}
191:
83:
843:
Enzymes catalyze reactions using general-acid and general-base catalysis.
219:, silico-alumino-phosphate), sulfated zirconia, and many transition metal
115:
55:
47:
925:
216:
212:
176:
952:
227:. Many solid Brønsted acids are also employed industrially, including
283:
In specific acid catalysis, protonated solvent is the catalyst. The
131:
39:
263:
220:
201:
187:
87:
223:(titania, zirconia, niobia, and more). Such acids are used in
521:
to the reaction product; for example, in the acid catalysed
360:
250:, e.g., the combination of benzene and ethylene to give
206:
Zeolite, ZSM-5 is widely used as a solid acid catalyst.
550:
376:
304:
254:. Another major application is the rearrangement of
828:
491:
344:
510:is in a fast equilibrium with its conjugate acid
359:the reaction rate for reactants R depends on the
345:{\displaystyle {\ce {S + AH -> SH+ + A-}}}
8:
246:A particularly large scale application is
182:Strong acids catalyze the hydrolysis and
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7:
517:which proceeds to react slowly with
42:binds to oxygens and functions as a
1030:Compendium of Chemical Terminology
1001:Compendium of Chemical Terminology
147:Acid catalysis is mainly used for
25:
190:, e.g. for processing fats into
96:Brønsted–Lowry acid–base theory
866:Bioresource Technology Reports
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134:operate by general catalysis.
1:
363:of the system but not on the
917:10.1016/j.apcata.2019.117180
905:Applied Catalysis A: General
878:10.1016/j.biteb.2018.04.007
355:For example, in an aqueous
231:, sulfonated carbon, solid
1082:
506:is observed when reactant
110:. In these reactions, the
98:, the acid is the proton (
138:Applications and examples
969:10.1002/14356007.a01_185
1043:10.1351/goldbook.G02609
1014:10.1351/goldbook.S05796
287:is proportional to the
1035:General acid catalysis
830:
493:
346:
229:sulfonated polystyrene
207:
67:
46:to activate the ester
36:Fischer esterification
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494:
347:
205:
169:polystyrene sulfonate
33:
548:
374:
367:of different acids.
302:
293:chemical equilibrium
198:Solid acid catalysts
165:toluenesulfonic acid
64:chemical equilibrium
256:cyclohexanone oxime
184:transesterification
54:, and converts the
1006:Specific catalysis
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539:diazonium coupling
489:
342:
279:Specific catalysis
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157:alkylation process
124:specific catalysis
118:group is a better
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34:In acid-catalyzed
1061:Chemical kinetics
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241:polyoxometallates
153:hydrofluoric acid
128:general catalysis
80:chemical reaction
27:Chemical reaction
16:(Redirected from
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50:(top row) as an
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104:esterifications
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144:
143:Brønsted acids
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112:conjugate acid
76:base catalysis
72:acid catalysis
58:into the good
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535:reaction rate
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502:This type of
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289:concentration
286:
285:reaction rate
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239:, and hetero
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60:leaving group
57:
53:
49:
45:
41:
37:
32:
19:
18:Acid catalyst
1028:
1020:
999:
991:
975:
959:
943:
908:
904:
894:
869:
865:
855:
842:
838:
532:
518:
514:
511:
507:
501:
354:
282:
274:
262:. Many alkyl
252:ethylbenzene
245:
209:
181:
146:
127:
123:
120:electrophile
100:hydrogen ion
75:
71:
69:
52:electrophile
926:2117/177256
541:reactions.
260:caprolactam
237:niobic acid
1055:Categories
911:: 117180.
847:References
248:alkylation
44:Lewis acid
1066:Catalysis
935:201217759
886:102573076
872:: 69–76.
840:ionized.
560:−
386:−
337:−
316:⟶
271:Mechanism
192:biodiesel
84:catalyzed
225:cracking
213:zeolites
177:zeolites
155:(in the
116:carbonyl
56:hydroxyl
48:carbonyl
217:alumina
149:organic
132:enzymes
130:. Many
114:of the
983:
933:
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264:amines
221:oxides
188:esters
86:by an
40:proton
38:, the
1025:IUPAC
996:IUPAC
931:S2CID
882:S2CID
94:. By
90:or a
981:ISBN
553:rate
379:rate
126:and
106:and
92:base
88:acid
78:, a
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1010:doi
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440:SH
361:pH
320:SH
313:AH
243:.
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215:,
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171:,
167:,
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567:d
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480:2
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449:]
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428:=
422:t
418:d
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397:[
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333:A
329:+
324:+
310:+
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211:(
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20:)
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