Hofmannn.

/ˈhɒfmən/

Etymology: < the name of August Wilhelm von Hofmann (1818–92), German chemist.

1. Used attributively and in the possessive to designate dyestuffs discovered and chemical apparatus and procedures devised by Hofmann.

a. Hofmann violet n. (also Hofmann's violet, Hoffman's Violet, Hofmann Violet) any of several basic dyes that are salts of ethyl and methyl derivatives of rosaniline and pararosaniline and were formerly used with wool, silk, and mordanted cotton.

ΘΚΠ

the world > matter > colour > named colours > purple or purpleness > purple dye or pigment > [noun]

turnsole1375

cork1483

jarecork1483

orchil1483

purple1519

purpurisse1519

archil1551

waycoriant1658

orchilla1703

cudbear1772

purple lake1785

imperial purple1788

mauve?1796

phenicin1823

French purple1830

indigo-purple1838

mauve1859

Perkin's mauve1859

violine1859

mauveine1863

purple of Cassiusc1865

tyroline1867

Paris violet1868

Hofmann violet1869

methyl violet1873

punicin1879

crystal violet1885

chrome violet1892

mineral violet1913

Monastral1936

manganese purple1937

1869 H. E. Roscoe Lessons Elem. Chem. (new ed.) xxxix. 385 Triethylrosaniline, C₂₀H₁₆(C₂H₅)₃N₃, is manufactured for its splendid colour, and is known as Hofmann's violet.

1875 Encycl. Brit. II. 48/2 Violet colours, such as Hofmann's violet.

1884 Bleaching, Dyeing, & Calico-printing 176 This dye [sc. violet imperial] is now replaced by the Hofmann violets.

1905 J. C. Cain & J. F. Thorpe Synthetic Dyestuffs xiv. 90 Hofmann's violet was the first violet dyestuff of this [rosaniline] series prepared, and is now merely of historical interest.

1952 K. Venkataraman Chem. Synthetic Dyes I. i. 3 In 1866 Bardy oxidized a mixture of mono- and dimethylanilines to Methyl Violet, which soon eliminated the Hofmann Violets.

b. Hofmann method n. (also Hofmann's method) (a) a method for finding the vapour density of a liquid (see quot. 1902¹); (b) the preparation of amines by means of the Hofmann degradation of amides.

ΘΚΠ

the world > matter > chemistry > chemical assay or analytical chemistry > [noun] > acetimetry > other analytical techniques

alkalimetry1817

refraction1831

Hofmann method1876

cryoscopy1885

Reichert–Meissl1887

oxidimetry1896

Hofmann exhaustive methylation1938

workup1942

radioactivation analysisa1947

neutron activation analysis1947

activation analysis1948

the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > preparation of amines

Hofmann method1876

1876 Encycl. Brit. V. 548/1 Gay-Lussac and Hofmann's Methods.

1902 J. B. Cohen Theoret. Org. Chem. iii. 30 Victor Meyer's method and Hofmann's method consist in ascertaining the volume occupied by a given weight of the vaporised substance.

1902 J. B. Cohen Theoret. Org. Chem. xiv. 195 If a primary amine is treated by Hofmann's method with an alkyl iodide in which the alkyl group is different from that present in the amine, a mixed amine is formed.

1949 J. R. Partington Adv. Treat. Physical Chem. I. vii. 760 In Hofmann's method, a uniform glass tube about 1 m. long..is supported in a glass jacket through which the vapour of a liquid, boiling in a separate vessel, is passed.

c. Hofmann apparatus n. (also Hofmann's apparatus)

ΚΠ

1876 Encycl. Brit. V. 548/1 (caption) Hofmann's Vapour-Density Apparatus.

1949 J. R. Partington Adv. Treat. Physical Chem. I. vii. 761 A modified Hofmann apparatus for accurate vapour-density determinations.

d. Hofmann reaction n. (also Hofmann's reaction) either of the Hofmann degradations.

ΘΚΠ

the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction

Hofmann reaction1902

1871 Jrnl. Chem. Soc. 24 406 On Hofmann's Tyrosine Reaction.]

1902 Jrnl. Chem. Soc. 82 ii. 663 Sodium hypochlorite is a more valuable reagent than the hypobromite in Hofmann's reaction.

e. Hofmann blue n. ((similarly Hofmann's green)) a blue dye used for staining.

ΚΠ

1886 A. H. Buck Ref. Handbk. Med. Sci. III. 677/2 Iodine Green, Hoffman's [sic] Green.

1902 Encycl. Brit. XXVII. 337/2 The basis of these methods consists in causing a swelling of the cell~wall..and subsequent staining with Hoffmann's blue.

f. Hofmann rearrangement n. (also Hofmann's rearrangement) the Hofmann degradation of amides.

ΘΚΠ

the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > pyrolysis of quaternary ammonium hydroxide

Hofmann rearrangement1910

Hofmann degradation1938

1910 Chem. Abstr. 4 583 (heading) Acid properties of halogen amides. Hofmann's rearrangement.

1968 R. O. C. Norman Princ. Org. Synthesis xiv. 446 (heading) Hofmann rearrangement.

g. Hofmann degradation n. (also Hofmann's degradation) (a) the elimination of a carbonyl group from an acid amide when it is heated in a sodium hypohalite solution, giving a primary amine; (b) the pyrolysis of a quaternary ammonium hydroxide to give a tertiary amine and an olefin.

ΘΚΠ

Hofmann rearrangement1910

Hofmann degradation1938

the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > elimination of carbonyl group

Hofmann degradation1938

1938 L. Small in H. Gilman Org. Chem. II. xii. 1024 The most generally applicable method for ascertaining structure is exhaustive methylation, also known as the Hofmann degradation.

1938 Thorpe's Dict. Appl. Chem. (ed. 4) II. 375/1 An important reaction of carboxylic acids is their conversion to amines by the Hofmann degradation, whereby the amide is treated with bromine and alkali.

1950 L. F. Fieser & M. Fieser Org. Chem. (ed. 2) xxxv. 865 The correct structure of the lobelia alkaloids..was first deduced from the result of Hofmann degradation of the quaternary hydroxide.

h. Hofmann exhaustive methylation n. (also Hofmann's exhaustive methylation) a method for determining the structure of amino compounds by methylation followed by pyrolysis, the resulting amine being subjected successively to the same procedure until trimethylamine and olefins are obtained; loosely, the Hofmann degradation n. (b) at sense 1g.

ΘΚΠ

the world > matter > chemistry > chemical assay or analytical chemistry > [noun] > acetimetry > other analytical techniques

alkalimetry1817

refraction1831

Hofmann method1876

cryoscopy1885

Reichert–Meissl1887

oxidimetry1896

Hofmann exhaustive methylation1938

workup1942

radioactivation analysisa1947

neutron activation analysis1947

activation analysis1948

1938 G. H. Richter Textbk. Org. Chem. xiv. 239 (heading) Hofmann's exhaustive methylation.

1938 G. H. Richter Textbk. Org. Chem. xiv. 241 The decomposition of these substances on heating to a high temperature has already been indicated in the Hofmann exhaustive methylation procedure.

i. Hofmann rule n. (also Hofmann's rule) (see quot. 1954).

ΘΚΠ

the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > Hofmann rule

Hofmann rule1951

1951 E. D. Hughes in E. H. Rodd Chem. Carbon Compounds I a. 183 The Hofmann rule refers to the preferential formation of that ethylene which bears the smallest number of alkyl groups.

1954 Van Nostrand Chem. Dict. 356/2 Hofmann rule, in the decomposition of a quaternary ammonium hydroxide containing different primary alkyl radicals, the products are such that the ethylene formed will contain the least number of alkyl substituents.

2. Hofmann's bacillus n. (also Hofmann bacillus) [ < the name of Georg von Hofmann-Wellenhof (d. c1890), Austrian bacteriologist] a non-pathogenic bacillus similar to the diphtheria bacillus and common in the nose and throat; variously known as Corynebacterium pseudodiphtheriticum, C. hofmanni, etc.

ΘΚΠ

the world > life > biology > organism > micro-organism > bacterium > bacillus > [noun] > types of

tubercle bacillus1882

Koch's bacillus1885

comma (bacillus)1886

spider-cell1888

Klebs–Löffler1895

Hofmann's bacillus1897

Koch–Weeks bacillus1898

Pfeiffer's bacillus1900

Shiga1900

Hansen('s) bacillus1903

streptobacilli1903

Johne's bacillus1907

wisp bacillus1915

klebsiella1928

Shigella1937

listerella1940

coliform1951

thiobacillus1951

1891 Johns Hopkins Hosp. Bull. 2 143/2 Kolisko and Paltauf..were able to find the pseudo-diphtheritic bacillus of von Hoffmann only very rarely.]

1897 Jrnl. Pathol. & Bacteriol. 4 190 The cases affected with Hofmann's bacillus unassociated with diphtheria bacilli, which have come under my notice, have always recovered.

1897 Trans. Brit. Inst. Prev. Med. 12 Peters..does not seem to have noticed any difference of growth of the Klebs-Löffler and von Hoffmann bacilli on alkaline potato.

1912 W. Osler Princ. & Pract. Med. (ed. 8) 60 Hoffmann's Bacillus, which is also spoken of as pseudo-diphtheria bacillus.

1959 F. S. Stewart Bigger's Handbk. Bacteriol. (ed. 7) xviii. 307 C. pseudodiphtheriticum (Hofmann's bacillus)..is often present in the nose and less frequently in the throat.

This entry has not yet been fully updated (first published 1976; most recently modified version published online June 2019).

单词	hofmann
释义	Hofmannn. /ˈhɒfmən/ Etymology: < the name of August Wilhelm von Hofmann (1818–92), German chemist. 1. Used attributively and in the possessive to designate dyestuffs discovered and chemical apparatus and procedures devised by Hofmann. a. Hofmann violet n. (also Hofmann's violet, Hoffman's Violet, Hofmann Violet) any of several basic dyes that are salts of ethyl and methyl derivatives of rosaniline and pararosaniline and were formerly used with wool, silk, and mordanted cotton. ΘΚΠ the world > matter > colour > named colours > purple or purpleness > purple dye or pigment > [noun] turnsole1375 cork1483 jarecork1483 orchil1483 purple1519 purpurisse1519 archil1551 waycoriant1658 orchilla1703 cudbear1772 purple lake1785 imperial purple1788 mauve?1796 phenicin1823 French purple1830 indigo-purple1838 mauve1859 Perkin's mauve1859 violine1859 mauveine1863 purple of Cassiusc1865 tyroline1867 Paris violet1868 Hofmann violet1869 methyl violet1873 punicin1879 crystal violet1885 chrome violet1892 mineral violet1913 Monastral1936 manganese purple1937 1869 H. E. Roscoe Lessons Elem. Chem. (new ed.) xxxix. 385 Triethylrosaniline, C₂₀H₁₆(C₂H₅)₃N₃, is manufactured for its splendid colour, and is known as Hofmann's violet. 1875 Encycl. Brit. II. 48/2 Violet colours, such as Hofmann's violet. 1884 Bleaching, Dyeing, & Calico-printing 176 This dye [sc. violet imperial] is now replaced by the Hofmann violets. 1905 J. C. Cain & J. F. Thorpe Synthetic Dyestuffs xiv. 90 Hofmann's violet was the first violet dyestuff of this [rosaniline] series prepared, and is now merely of historical interest. 1952 K. Venkataraman Chem. Synthetic Dyes I. i. 3 In 1866 Bardy oxidized a mixture of mono- and dimethylanilines to Methyl Violet, which soon eliminated the Hofmann Violets. b. Hofmann method n. (also Hofmann's method) (a) a method for finding the vapour density of a liquid (see quot. 1902¹); (b) the preparation of amines by means of the Hofmann degradation of amides. ΘΚΠ the world > matter > chemistry > chemical assay or analytical chemistry > [noun] > acetimetry > other analytical techniques alkalimetry1817 refraction1831 Hofmann method1876 cryoscopy1885 Reichert–Meissl1887 oxidimetry1896 Hofmann exhaustive methylation1938 workup1942 radioactivation analysisa1947 neutron activation analysis1947 activation analysis1948 the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > preparation of amines Hofmann method1876 1876 Encycl. Brit. V. 548/1 Gay-Lussac and Hofmann's Methods. 1902 J. B. Cohen Theoret. Org. Chem. iii. 30 Victor Meyer's method and Hofmann's method consist in ascertaining the volume occupied by a given weight of the vaporised substance. 1902 J. B. Cohen Theoret. Org. Chem. xiv. 195 If a primary amine is treated by Hofmann's method with an alkyl iodide in which the alkyl group is different from that present in the amine, a mixed amine is formed. 1949 J. R. Partington Adv. Treat. Physical Chem. I. vii. 760 In Hofmann's method, a uniform glass tube about 1 m. long..is supported in a glass jacket through which the vapour of a liquid, boiling in a separate vessel, is passed. c. Hofmann apparatus n. (also Hofmann's apparatus) ΚΠ 1876 Encycl. Brit. V. 548/1 (caption) Hofmann's Vapour-Density Apparatus. 1949 J. R. Partington Adv. Treat. Physical Chem. I. vii. 761 A modified Hofmann apparatus for accurate vapour-density determinations. d. Hofmann reaction n. (also Hofmann's reaction) either of the Hofmann degradations. ΘΚΠ the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction Hofmann reaction1902 1871 Jrnl. Chem. Soc. 24 406 On Hofmann's Tyrosine Reaction.] 1902 Jrnl. Chem. Soc. 82 ii. 663 Sodium hypochlorite is a more valuable reagent than the hypobromite in Hofmann's reaction. e. Hofmann blue n. ((similarly Hofmann's green)) a blue dye used for staining. ΚΠ 1886 A. H. Buck Ref. Handbk. Med. Sci. III. 677/2 Iodine Green, Hoffman's [sic] Green. 1902 Encycl. Brit. XXVII. 337/2 The basis of these methods consists in causing a swelling of the cell~wall..and subsequent staining with Hoffmann's blue. f. Hofmann rearrangement n. (also Hofmann's rearrangement) the Hofmann degradation of amides. ΘΚΠ the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > pyrolysis of quaternary ammonium hydroxide Hofmann rearrangement1910 Hofmann degradation1938 1910 Chem. Abstr. 4 583 (heading) Acid properties of halogen amides. Hofmann's rearrangement. 1968 R. O. C. Norman Princ. Org. Synthesis xiv. 446 (heading) Hofmann rearrangement. g. Hofmann degradation n. (also Hofmann's degradation) (a) the elimination of a carbonyl group from an acid amide when it is heated in a sodium hypohalite solution, giving a primary amine; (b) the pyrolysis of a quaternary ammonium hydroxide to give a tertiary amine and an olefin. ΘΚΠ the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > pyrolysis of quaternary ammonium hydroxide Hofmann rearrangement1910 Hofmann degradation1938 the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > elimination of carbonyl group Hofmann degradation1938 1938 L. Small in H. Gilman Org. Chem. II. xii. 1024 The most generally applicable method for ascertaining structure is exhaustive methylation, also known as the Hofmann degradation. 1938 Thorpe's Dict. Appl. Chem. (ed. 4) II. 375/1 An important reaction of carboxylic acids is their conversion to amines by the Hofmann degradation, whereby the amide is treated with bromine and alkali. 1950 L. F. Fieser & M. Fieser Org. Chem. (ed. 2) xxxv. 865 The correct structure of the lobelia alkaloids..was first deduced from the result of Hofmann degradation of the quaternary hydroxide. h. Hofmann exhaustive methylation n. (also Hofmann's exhaustive methylation) a method for determining the structure of amino compounds by methylation followed by pyrolysis, the resulting amine being subjected successively to the same procedure until trimethylamine and olefins are obtained; loosely, the Hofmann degradation n. (b) at sense 1g. ΘΚΠ the world > matter > chemistry > chemical assay or analytical chemistry > [noun] > acetimetry > other analytical techniques alkalimetry1817 refraction1831 Hofmann method1876 cryoscopy1885 Reichert–Meissl1887 oxidimetry1896 Hofmann exhaustive methylation1938 workup1942 radioactivation analysisa1947 neutron activation analysis1947 activation analysis1948 1938 G. H. Richter Textbk. Org. Chem. xiv. 239 (heading) Hofmann's exhaustive methylation. 1938 G. H. Richter Textbk. Org. Chem. xiv. 241 The decomposition of these substances on heating to a high temperature has already been indicated in the Hofmann exhaustive methylation procedure. i. Hofmann rule n. (also Hofmann's rule) (see quot. 1954). ΘΚΠ the world > matter > chemistry > organic chemistry > chemical processes or reactions > processes or reactions attributed to chemists > [noun] > Hofmann's reaction > Hofmann rule Hofmann rule1951 1951 E. D. Hughes in E. H. Rodd Chem. Carbon Compounds I a. 183 The Hofmann rule refers to the preferential formation of that ethylene which bears the smallest number of alkyl groups. 1954 Van Nostrand Chem. Dict. 356/2 Hofmann rule, in the decomposition of a quaternary ammonium hydroxide containing different primary alkyl radicals, the products are such that the ethylene formed will contain the least number of alkyl substituents. 2. Hofmann's bacillus n. (also Hofmann bacillus) [ < the name of Georg von Hofmann-Wellenhof (d. c1890), Austrian bacteriologist] a non-pathogenic bacillus similar to the diphtheria bacillus and common in the nose and throat; variously known as Corynebacterium pseudodiphtheriticum, C. hofmanni, etc. ΘΚΠ the world > life > biology > organism > micro-organism > bacterium > bacillus > [noun] > types of tubercle bacillus1882 Koch's bacillus1885 comma (bacillus)1886 spider-cell1888 Klebs–Löffler1895 Hofmann's bacillus1897 Koch–Weeks bacillus1898 Pfeiffer's bacillus1900 Shiga1900 Hansen('s) bacillus1903 streptobacilli1903 Johne's bacillus1907 wisp bacillus1915 klebsiella1928 Shigella1937 listerella1940 coliform1951 thiobacillus1951 1891 Johns Hopkins Hosp. Bull. 2 143/2 Kolisko and Paltauf..were able to find the pseudo-diphtheritic bacillus of von Hoffmann only very rarely.] 1897 Jrnl. Pathol. & Bacteriol. 4 190 The cases affected with Hofmann's bacillus unassociated with diphtheria bacilli, which have come under my notice, have always recovered. 1897 Trans. Brit. Inst. Prev. Med. 12 Peters..does not seem to have noticed any difference of growth of the Klebs-Löffler and von Hoffmann bacilli on alkaline potato. 1912 W. Osler Princ. & Pract. Med. (ed. 8) 60 Hoffmann's Bacillus, which is also spoken of as pseudo-diphtheria bacillus. 1959 F. S. Stewart Bigger's Handbk. Bacteriol. (ed. 7) xviii. 307 C. pseudodiphtheriticum (Hofmann's bacillus)..is often present in the nose and less frequently in the throat. This entry has not yet been fully updated (first published 1976; most recently modified version published online June 2019). < n.1869
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