Interstellar Molecules and Dense Clouds

Rank, D. M.; Townes, C. H.; Welch, W. J.

doi:10.1126/science.174.4014.1083

Cited by 179 publications

(33 citation statements)

References 88 publications

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“…3 The Butlerow reaction, the synthesis of a complex mixture of sugars from formaldehyde by the action of alkaline catalysts such as calcium hydroxide, was discovered in the nineteenth century.4 Analysis by paper chromatography has demonstrated that the pentose sugars, ribose and arabinose, are among the products.5 Recent work on the prebiotic synthesis of sugars has shown that, in the presence of mineral catalysts, the polymerization of formaldehyde to sugars proceeds rapidly a t lOO"C, and presumably more slowly under milder conditions that could have occurred on the primitive earth.637 We shall not discuss this reaction in detail, since little work on it has been undertaken in our laboratory.…”

Section: Prebiotic Formation Of Sugars and Basesmentioning

confidence: 99%

Prebiotic chemistry and nucleic acid replication

Orgel¹,

Lohrmann²

1974

Acc. Chem. Res.

235

119

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Accounts of Chemical Research tions51 concerning the above interpretation, it provides the most direct explanation of the experimental observations, and is preferred by the writer. Some support can be derived from the fact that related adducts do in fact undergo 6-and 8-bromination.53 It is likely that similar reaction paths, available because of the easy reversibility of attachment of halogen to nitrogen, are to be found with related heterocyclic systems. Reversibility in Aromatic Substitution: Applicability of Linear Free-Energy Relationships Involving Partial Rate Factors for Aromatic SubstitutionThe qualitative electronic theory of organic chemistry, together with attempts to put this theory in quantitative terms by using linear free-energy relationships or by making molecular orbital calculations concerning the relative availability of transition states, involves a number of assumptions which are not always stated explicitly. One of these is that the rate-determining transition states which are being compared have similar compositions and bonding characters. When this is not so, deviations from predicted rates and orientations are expected as possi-bilities, though they are not required. Thus it is by no means clear that two aromatic substitutions, one of which shows a primary H-D isotope effect and one of which does not, should give a reasonable linear free-energy relationship between their relative reaction rates. Quite good correlations are, in fact, found in a number of cases,21 but Berliner and his cowork-er@ have illustrated how reversibility of the first stages of substitution (reactions b and c, Scheme I) can influence the orientation of the products in suitable cases. This provides one example of a number of ways in which the detailed chemistry of the carbocations and other intermediates leading to electrophilic substitution in unsaturated systems can be important in determining the relative rates at which particular products are formed.T h i s Account has surveyed a n u m b e r of examples t o t h e understanding of which t h e writers' couorkers have m a d e contributions; it gives quite inadequate acknowledgment of his personal indebtedness to t h e m , as it does also to t h e m a n y other groups of workers contributing actively to our knowledge of these reactions.

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Section: Prebiotic Formation Of Sugars and Basesmentioning

confidence: 99%

Prebiotic chemistry and nucleic acid replication

Orgel¹,

Lohrmann²

1974

Acc. Chem. Res.

235

119

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“…Hints of this situation were already apparent in the first detections of polyatomic molecules in interstellar space in the late 1960's (1). The initial observations of OH-and H20 emission at centimeter wavelengths showed evidence of material in interstellar clouds moving at velocities along the line of sight in excess of 100 km/sec.…”

mentioning

confidence: 92%

Gas Jets Associated with Star Formation

Welch

Vogel

Plambeck

et al. 1985

Science

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Young stellar objects of both high and low luminosity emit energetic jets or winds of material that are often highly collimated and often bipolar. Near the stars, turbulent swept-up gas is observed in the emission of interstellar molecules such as carbon monoxide, and small, bright regions of water maser emission and the nebulous bright patches known as Herbig-Haro objects appear to be participating in the outflows. There are striking changes in chemical abundances associated with the attendant shocks. Probably every star goes through this phase, which may mark the end of its period of accretion.

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“…Carbon monoxide gas is ubiquitous in giant molecular clouds associated with regions of active star formation (Rank et al 1971, Turner 1989; its high volatility makes it an excellent probe of conditions in cold shielded regions such as the natal clouds around young planetary systems (Chiar et al 1995, Whittet et al 1996. CO is found in both H 2 O-rich (polar) and H 2 O-poor (nonpolar) icy mantles on dust grains, depending on local conditions.…”

Section: Introductionmentioning

confidence: 99%